CN117336642A

CN117336642A - Earphone

Info

Publication number: CN117336642A
Application number: CN202210726963.4A
Authority: CN
Inventors: 张磊; 付峻江; 王真; 廖风云; 齐心
Original assignee: Shenzhen Voxtech Co Ltd
Current assignee: Shenzhen Voxtech Co Ltd
Priority date: 2022-06-24
Filing date: 2022-06-24
Publication date: 2024-01-02

Abstract

The embodiment of the specification discloses an earphone, which comprises a first sound wave generating structure, a second sound wave generating structure, an acoustic transmission structure and a filtering structure. The first sound wave generating structure and the second sound wave generating structure may generate a first sound wave and a second sound wave, respectively, the first sound wave and the second sound wave having a phase difference in the range of 120 ° -240 °. The acoustic transmission structure may be configured to transmit the first acoustic wave and the second acoustic wave to a spatial point outside the earpiece, wherein the first acoustic wave and the second acoustic wave transmitted to the spatial point may interfere in a first frequency range, the interference reducing an amplitude of the first acoustic wave in the first frequency range. The filtering structure may be used to reduce the amplitude of sound waves at the spatial point in the second frequency range.

Description

Earphone

Technical Field

The present disclosure relates to the field of acoustics, and in particular, to an earphone.

Background

Headphones are a portable audio output device that can achieve sound conduction. To solve the problem of leakage of headphones, two or more sound sources are typically used to emit two opposite-phase acoustic signals. Under far field conditions, the difference in sound path between two sound sources with opposite phases reaching a point in the far field is basically negligible, so that the two sound signals can cancel each other to reduce far field leakage. Although the method can achieve the effect of reducing the leakage sound to a certain extent, certain limitations still exist. For example, due to the shorter wavelength of the high frequency leakage, the distance between the two sound sources is not negligible compared to the wavelength in far field conditions, resulting in that the sound signals emitted by the two sound sources cannot be cancelled. For example, when the acoustic transmission structure of the earphone resonates, a certain phase difference exists between the phase of the acoustic signal actually radiated by the sound outlet of the earphone and the original phase of the sound wave generating position, which also easily causes that the two acoustic signals cannot be counteracted, and it is difficult to ensure the sound leakage reducing effect of the far field under high frequency.

Accordingly, it is desirable to provide an earphone that can reduce leakage.

Disclosure of Invention

Embodiments of the present disclosure provide an earphone including a first sound wave generating structure and a second sound wave generating structure, which may generate a first sound wave and a second sound wave, respectively, and may have a phase difference, which may be in the range of 120 ° -240 °. The earphone may further comprise an acoustic transmission structure and a filtering structure. The acoustic transmission structure may be configured to transmit a first acoustic wave and a second acoustic wave to a point in space outside the earpiece, wherein the first acoustic wave and the second acoustic wave transmitted to the point in space may interfere in a first frequency range, and the interference may reduce the amplitude of the first acoustic wave in the first frequency range. The filtering structure may be adapted to reduce the amplitude of sound waves at the spatial point in a second frequency range.

Embodiments of the present disclosure provide an earphone including a first sound wave generating structure, an acoustic transmitting structure, and a filtering structure. The acoustic transmission structure can be used for transmitting the first sound wave generated by the first sound wave generating structure to a space point outside the earphone, wherein the first sound wave can generate resonance with resonance frequency under the action of the acoustic transmission structure. The filtering structure may be configured to absorb sound waves in a target frequency range of the first sound wave after being transferred through the acoustic transmission structure to reduce an amplitude of the sound wave received at the spatial point, wherein the target frequency range may include the resonant frequency.

Embodiments of the present disclosure provide an earphone including a speaker, a housing, and a filtering structure. The housing may be adapted to carry the speaker and have first and second aperture portions in acoustic communication with the speaker, respectively, through which the speaker may output sound waves having a phase difference. The filtering structure may be disposed in an acoustic transmission structure between the first hole portion or the second hole portion and the speaker, for absorbing sound waves of a target frequency range, wherein the target frequency range may be in a range of 1kHz to 10 kHz.

Drawings

The present specification will be further elucidated by way of example embodiments, which will be described in detail by means of the accompanying drawings. The embodiments are not limiting, in which like numerals represent like structures, wherein:

FIG. 1 is an exemplary block diagram of an open earphone according to some embodiments of the present description;

FIG. 2 is a schematic illustration of two point sound sources provided in accordance with some embodiments of the present description;

FIG. 3 is a schematic illustration of two point sound sources and listening positions provided in accordance with some embodiments of the present description;

Fig. 4 is a frequency response plot of dipole sound sources of different spacing at near-field listening locations provided in accordance with some embodiments of the present disclosure;

FIG. 5 is a plot of leakage index at the far field for dipole sources of different spacing provided in accordance with some embodiments of the present disclosure;

FIG. 6 is an exemplary distribution diagram of baffles disposed between dipole sound sources provided according to some embodiments of the present disclosure;

fig. 7 is a frequency response characteristic of a near field when an auricle is located between dipole sound sources provided according to some embodiments of the present disclosure;

fig. 8 is a frequency response curve of the far field of an auricle between dipole sound sources provided according to some embodiments of the present disclosure;

FIG. 9 is a graph of leakage index for different modes provided in accordance with some embodiments of the present disclosure;

FIG. 10 is a measurement schematic of a leak sound index provided in accordance with some embodiments of the present disclosure;

FIG. 11 is a graph of frequency response between two point sound sources with or without baffles provided in accordance with some embodiments of the present description;

FIG. 12 is a plot of sound pressure amplitude for a dipole sound source at 300Hz at different spacings provided in accordance with some embodiments of the present disclosure;

FIG. 13 is a plot of sound pressure amplitude for a dipole sound source at 1000Hz at different spacings provided in accordance with some embodiments of the present disclosure;

FIG. 14 is a plot of sound pressure amplitude for a dipole sound source at 5000Hz at different spacings provided in accordance with some embodiments of the present disclosure;

fig. 15 is a near field frequency response characteristic of a dipole sound source spacing d of 1cm provided in accordance with some embodiments of the present disclosure;

fig. 16 is a near field frequency response characteristic of a dipole sound source spacing d of 2cm provided in accordance with some embodiments of the present disclosure;

fig. 17 is a near field frequency response characteristic of a dipole sound source spacing d of 4cm provided in accordance with some embodiments of the present disclosure;

FIG. 18 is a plot of the leakage index of the far field for a dipole sound source spacing d of 1cm provided in accordance with some embodiments of the present disclosure;

FIG. 19 is a plot of the leakage index of the far field for a dipole sound source spacing d of 2cm provided in accordance with some embodiments of the present disclosure;

FIG. 20 is a plot of the leakage index of the far field for a dipole sound source spacing d of 4cm, provided in accordance with some embodiments of the present disclosure;

fig. 21A is a schematic diagram of a baffle-less dipole sound source in near-field different listening positions provided in accordance with some embodiments of the present description;

FIG. 21B is a graph of various levels of baffle versus listening position drop leakage capability when the baffle is not present, according to some embodiments of the present disclosure;

Fig. 22 is a graph of frequency response characteristics of a baffle-free dipole sound source at different listening positions in the near field, provided in accordance with some embodiments of the present disclosure;

FIG. 23 is a plot of leakage indices of a baffle-free dipole sound source at different listening positions in the near field, provided in accordance with some embodiments of the present disclosure;

fig. 24 is a graph of frequency response characteristics of a baffle-mounted dipole sound source (as in the case of fig. 21A) at different listening positions in the near field, provided in accordance with some embodiments of the present disclosure;

FIG. 25 is a graph of leakage index for different listening positions provided in accordance with some embodiments of the present description;

FIG. 26 is an exemplary distribution diagram of two hole portions and pinna provided in accordance with some embodiments of the present disclosure;

FIG. 27 is a plot of the frequency response of the near field for baffles at different positions provided in accordance with some embodiments of the present disclosure;

FIG. 28 is a frequency response curve of the far field of a baffle at different locations provided in accordance with some embodiments of the present disclosure;

FIG. 29 is a graph of the leakage index of a baffle in various positions provided in accordance with some embodiments of the present disclosure;

FIG. 30 is a schematic diagram of a cell phone having a hole portion according to some embodiments of the present disclosure;

FIG. 31 is an exemplary block diagram of an open earphone according to some embodiments of the present disclosure;

fig. 32 is a schematic distribution diagram of baffles with different tilt angles between dipole sound sources according to some embodiments of the present disclosure;

fig. 33 is a frequency response characteristic of the dipole sound source in the near field when the baffle of different inclination angles is employed in fig. 32;

fig. 34 is a frequency response curve of the dipole sound source in the far field when the baffle of different inclination angles is employed in fig. 32;

FIG. 35 is a plot of the leakage index generated in accordance with FIGS. 32 and 33;

FIG. 36 is an exemplary distribution schematic of dipole sound sources and baffles provided in accordance with some embodiments of the present disclosure;

fig. 37 is a frequency response curve of a near field of a dipole sound source when baffles of different heights are selected in the structure shown in fig. 36;

FIG. 38 is a frequency response plot of the far field of the dipole sound source for different heights of baffles selected in the configuration shown in FIG. 36;

FIG. 39 is a plot of the leakage index of a dipole sound source for a selection of baffles of different heights in the configuration shown in FIG. 36;

FIGS. 40A and 40B are graphs of hole portions versus listening position provided in accordance with some embodiments of the present description;

Fig. 41 is a frequency response characteristic of a near field of the dipole sound source when the ratio of the distance from the center of the baffle to the line connecting the dipole sound sources to the height of the baffle in the structure of fig. 36 takes different values;

FIG. 42 is a plot of the frequency response of the far field of the dipole sound source for the configuration of FIG. 36 where the ratio of the distance from the center of the baffle to the line of the dipole sound source to the height of the baffle is different;

FIG. 43 is a plot of the leakage index for the baffle center to dipole sound source line distance versus baffle height for the configuration of FIG. 36;

FIG. 44 is a plot of the frequency response of the near field of a low frequency acoustic impedance baffle provided in accordance with some embodiments of the present disclosure between dipole sound sources;

FIG. 45 is a frequency response curve of the far field of a low frequency acoustic impedance baffle provided in accordance with some embodiments of the present disclosure when positioned between dipole sound sources;

FIG. 46 is a schematic diagram of the structure of several acoustic structures shown in accordance with some embodiments of the present disclosure;

FIG. 47 is a schematic view of a baffle structure of different shapes according to some embodiments of the present disclosure;

FIG. 48 is a schematic view of a cell phone having a hole portion and a baffle structure according to some embodiments of the present disclosure;

FIG. 49 is a schematic diagram of a distribution of point sound sources and baffles shown in accordance with some embodiments of the present disclosure;

Fig. 50 is a frequency response characteristic of near and far fields according to the arrangement and non-arrangement of baffles between the multi-point sound sources shown in fig. 49;

fig. 51 is a graph of a leakage index according to the arrangement and non-arrangement of baffles between the plurality of point sound sources shown in fig. 49;

fig. 52 is a graph of leakage index corresponding to the two multipoint sound source distribution modes shown in fig. 49 (a) and (b);

FIG. 53 is an exemplary structural diagram of another open earphone according to some embodiments of the present description;

FIG. 54 is a graph of leakage of dipole and single point sources as shown according to some embodiments of the present disclosure as a function of frequency;

55A and 55B are exemplary graphs of near-field listening volume and far-field leakage volume as a function of dipole sound source spacing according to some embodiments of the present description;

FIG. 56 is an exemplary block diagram of an open earphone according to some embodiments of the present disclosure;

FIG. 57 is an exemplary flow chart of an acoustic output method according to some embodiments of the present description;

FIG. 58 is a schematic diagram of an open earphone according to some embodiments of the present disclosure;

59A and 59B are schematic diagrams of sound output according to some embodiments of the present description;

FIGS. 60-61B are schematic diagrams of acoustic paths shown according to some embodiments of the present description;

FIG. 62A is an exemplary graph of leakage under the combined action of two sets of dipole sound sources according to some embodiments of the present disclosure;

FIG. 62B is a normalized plot of leakage shown in accordance with some embodiments of the present description;

FIG. 63A is a plot of listening and leaking of a dipole sound source at a particular frequency as a function of the amplitude ratio of two point sound sources, according to some embodiments of the present disclosure;

fig. 63B is a plot of listening and leakage of a dipole sound source at a particular frequency as a function of phase difference between two point sound sources, according to some embodiments of the present disclosure;

FIG. 64A is a position profile of two sets of dipole sound sources according to some embodiments of the present disclosure;

FIGS. 64B and 64C are graphs of sound guide parameters versus sound frequency variation according to some embodiments of the present description;

fig. 65A is a graph showing the results of sound pressures of sound output by sound guides of different lengths according to some embodiments of the present disclosure;

FIG. 65B is a graph of experimental test leakage reduction effects according to some embodiments of the present disclosure;

FIG. 66 is a graph of the effect of phase differences between two sets of dipole sound sources on earphone output sound according to some embodiments of the present disclosure;

FIGS. 67-69B are exemplary graphs illustrating leakage under the combined action of two sets of dipole sound sources according to some embodiments of the present disclosure;

FIG. 69C is a plot of the frequency response of a low frequency speaker and a high frequency speaker shown in accordance with some embodiments of the present description;

FIGS. 70A and 70B are schematic diagrams of four-point sound sources according to some embodiments of the present description;

FIG. 71 is a schematic diagram of dipole sound sources and listening positions shown in accordance with some embodiments of the present description;

FIG. 72 is a graph of the result of normalizing FIG. 71;

FIGS. 73A and 73B are exemplary graphs of leakage under the combined action of two sets of dipole sound sources according to some embodiments of the present disclosure;

fig. 73C is a crossover flow chart of a narrowband speaker dipole sound source shown in accordance with some embodiments of the present description;

FIG. 73D is a crossover flow chart of a full band speaker dipole sound source according to some embodiments of the present disclosure;

FIG. 74 is a schematic illustration of a cell phone having a multiple hole feature according to some embodiments of the present disclosure;

FIG. 75 is a schematic diagram of an earphone according to some embodiments of the present disclosure;

fig. 76A is a schematic diagram of sound pressure level sound field distribution at low frequencies for the structure shown in fig. 75;

FIG. 76B is a schematic illustration of the sound pressure level sound field distribution of the structure of FIG. 75 at resonance;

fig. 77A is a schematic diagram of a headset according to some embodiments of the present disclosure;

FIG. 77B is a schematic view of a first sound path and a second sound path in the earphone of FIG. 77A;

78A-78C are schematic illustrations of resistive sound absorption structures according to some embodiments of the present disclosure;

79A-79D are schematic illustrations of perforated plate structures shown in accordance with some embodiments of the present description;

FIG. 79E is a schematic illustration of a 1/4 wavelength resonance tube structure shown in accordance with some embodiments of the present disclosure;

FIG. 80 is a schematic illustration of an impedance hybrid sound absorbing structure shown in accordance with some embodiments of the present description;

FIG. 81 is a schematic diagram of an earphone provided with a filtering structure shown in accordance with some embodiments of the present description;

fig. 82A is a graph of the frequency response of the earphone of fig. 81 at the first aperture portion with or without the filtering structure;

fig. 82B is a graph of the frequency response of the earphone of fig. 81 at the second aperture portion with or without the filtering structure;

fig. 83 is a schematic diagram of an earphone provided with a filtering structure according to some embodiments of the present description;

fig. 84A is a graph of the frequency response of the earphone of fig. 83 at the first aperture portion with or without the filtering structure;

Fig. 84B is a graph of the frequency response of the earphone of fig. 83 at the second aperture portion with or without the filtering structure;

FIG. 85A is a schematic diagram of an earphone provided with a 1/4 wavelength resonating tube structure according to some embodiments of the present description;

FIG. 85B is a schematic perspective view of a 1/4 wavelength resonance tube structure according to some embodiments of the present disclosure;

fig. 86A is a graph of the frequency response of the earphone of fig. 85A at the first aperture portion with or without the filtering structure;

fig. 86B is a graph of the frequency response of the earphone shown in fig. 85A at the second aperture portion with or without the filter structure.

Detailed Description

In order to more clearly illustrate the technical solutions of the embodiments of the present specification, the drawings that are required to be used in the description of the embodiments will be briefly described below. It is apparent that the drawings in the following description are only some examples or embodiments of the present specification, and it is possible for those of ordinary skill in the art to apply the present specification to other similar situations according to the drawings without inventive effort. Unless otherwise apparent from the context of the language or otherwise specified, like reference numerals in the figures refer to like structures or operations.

It will be appreciated that "system," "apparatus," "unit" and/or "module" as used herein is one method for distinguishing between different components, elements, parts, portions or assemblies at different levels. However, if other words can achieve the same purpose, the words can be replaced by other expressions.

As used in this specification and the claims, the terms "a," "an," "the," and/or "the" are not specific to a singular, but may include a plurality, unless the context clearly dictates otherwise. In general, the terms "comprises" and "comprising" merely indicate that the steps and elements are explicitly identified, and they do not constitute an exclusive list, as other steps or elements may be included in a method or apparatus.

A flowchart is used in this specification to describe the operations performed by the system according to embodiments of the present specification. It should be appreciated that the preceding or following operations are not necessarily performed in order precisely. Rather, the steps may be processed in reverse order or simultaneously. Also, other operations may be added to or removed from these processes.

The present description describes an open earphone. When the user wears the open earphone, the open earphone can be fixed on the head of the user through the shell, so that the loudspeaker is positioned near the ear of the user and does not block the auditory canal of the user. The open headphones may be worn on the user's head (e.g., an open headphone worn in eyeglasses or other structures), or worn on other parts of the user's body (e.g., the neck/shoulder area of the user), or otherwise (e.g., hand-held) placed near the user's ears. The open earphone may include a speaker and a housing. Wherein the housing is configured to carry the speaker and has two aperture portions (e.g., a first aperture portion and a second aperture portion) in acoustic communication with the speaker, through which the speaker can output first and second sound waves having a phase difference. The housing and the aperture in the housing may form an acoustic transmission structure of the open earphone for transmitting the first sound wave and the second sound wave to a point in space outside the open earphone.

In some embodiments, the open earphone may further comprise a filtering structure, which may refer to a structure having a modulating effect on the frequency characteristics of the sound waves. In some embodiments, the filtering structure may include a sound absorbing structure that may be used to absorb sound waves in a target frequency range in the first sound wave and/or the second sound wave. The target frequency range may include frequencies greater than or equal to a resonant frequency of the acoustic transmission structure. The first sound wave and the second sound wave in a frequency range (or referred to as a first frequency range) smaller than the resonance frequency are not absorbed by the sound absorbing structure, and the first sound wave and the second sound wave in the frequency range can interfere and cancel at a spatial point due to a phase difference (for example, opposite phases), so that the amplitude of the first sound wave in the first frequency range is reduced, and the effect of dipole leakage reduction is achieved. And because the first sound wave and/or the second sound wave in the target frequency range (or called the second frequency range) are absorbed by the sound absorption structure, resonance of the first sound wave and/or the second sound wave around the resonance frequency under the action of the sound transmission structure can be reduced or avoided, so that interference cancellation (even interference enhancement and leakage increase) of the first sound wave and/or the second sound wave at a space point can not be caused due to the change of the phase and/or the amplitude after resonance can be reduced or avoided, and the amplitude of the sound wave in the target frequency range at the space point can be reduced. In some embodiments, the resonant frequency may occur in a mid-high frequency range (e.g., 2 kHz-8 kHz), and a target frequency range may include a high frequency greater than the resonant frequency of the acoustic transmission structure, thereby improving the problem of undesirable leakage effects of the dipole in the high frequency range.

Fig. 1 is an exemplary block diagram of an open earphone according to some embodiments of the present description.

As shown in fig. 1, the open earphone 100 may include a housing 110 and a speaker 120. In some embodiments, the open earphone 100 may be worn on the body of the user (e.g., the head, neck, or upper torso of a human body) through the housing 110, while the housing 110 and speaker 120 may be positioned adjacent to but not occluding the ear canal so that the user's ear 101 remains open and the user can hear sound output by the open earphone 100 while also capturing sound from the external environment. For example, the open earphone 100 may be disposed around or partially around the circumference of the user's ear 101, and may transmit sound by means of air conduction or bone conduction.

In some embodiments, housing 110 may be adapted to be worn on the body of a user and may carry speaker 120. In some embodiments, the housing 110 may be a closed housing structure with a hollow interior, and the speaker 120 is located inside the housing 110. In some embodiments, the open earphone 100 may be combined with eyeglasses, headphones, a head mounted display device, an AR/VR helmet, or the like, in which case the housing 110 may be secured in a hanging or clamping manner about the user's ear 101. In some alternative embodiments, the housing 110 may be provided with a hook, and the shape of the hook matches that of the auricle, and the open earphone 100 may be independently worn by the hook on the user's ear 101.

In some embodiments, the housing 110 may be a housing structure having a shape that fits the human ear 101, e.g., a ring shape, an oval shape, a polygon shape (regular or irregular), a U-shape, a V-shape, a semi-circle shape, so that the housing 110 may hang directly against the user's ear 101. In some embodiments, the housing 110 may also include a securing structure. The fixing structure may include an ear hook, an elastic band, etc., so that the open earphone 100 may be better fixed on the user, preventing the user from falling off when in use.

In some embodiments, the housing 110 may be located above or below the user's ear 101 when the user wears the open ended earphone 100. The housing 110 may be further provided with a hole 111 (or referred to as a second hole) and a hole 112 (or referred to as a first hole) for transmitting sound. In some embodiments, the hole parts 111 and 112 may be located at both sides of the auricle of the user, respectively, and the speaker 120 may output sounds having a phase difference through the hole parts 111 and 112. In some embodiments, as shown in fig. 1, aperture 112 may be located on the anterior side of a user's pinna and aperture 111 may be located on the posterior side of the user's pinna.

Speaker 120 is a device that receives an electrical signal and converts it into an acoustic signal for output. In some embodiments, the types of speakers 120 may include low frequency (e.g., 30Hz-150 Hz) speakers, medium low frequency (e.g., 150Hz-500 Hz) speakers, medium high frequency (e.g., 500Hz-5 kHz) speakers, high frequency (e.g., 5kHz-16 kHz) speakers, or full frequency (e.g., 30Hz-16 kHz) speakers, or any combination thereof, differentiated by frequency. The low frequency, the high frequency, and the like herein represent only the approximate range of frequencies, and may have different division schemes in different application scenarios. For example, a frequency division point may be determined, where a low frequency indicates a frequency range below the frequency division point and a high frequency indicates a frequency above the frequency division point. The crossover point may be any value within the audible range of the human ear, e.g., 500Hz,600Hz,700Hz,800Hz,1000Hz, etc.

In some embodiments, the interior of the housing 110 may be provided with a movement 121 and a main board 122, the movement 121 may constitute at least part of the structure of the speaker 120, and the speaker 120 may be capable of generating sounds with the movement 121, which are respectively transferred to and output from the corresponding hole portions along the corresponding acoustic paths. Motherboard 122 may be electrically connected to movement 121 to control the sounding of movement 121. In some embodiments, motherboard 122 may be disposed on housing 110 near movement 121 to shorten the routing distance from movement 121 and other components (e.g., function keys).

In some embodiments, speaker 120 may include a diaphragm. When the diaphragm vibrates, sound may be emitted from the front and rear sides of the diaphragm, respectively. In some embodiments, a front chamber 113 for transmitting sound is provided in the housing 110 at a position on the front side of the diaphragm. The front chamber 113 is acoustically coupled to the aperture 111, and sound from the front side of the diaphragm can be emitted from the aperture 111 through the front chamber 113. A rear chamber 114 for transmitting sound is provided in the housing 110 at a position on the rear side of the diaphragm. The rear chamber 114 is acoustically coupled to the aperture 112 and sound from the rear side of the diaphragm may be emitted from the aperture 112 through the rear chamber 114. In some embodiments, cartridge 121 may include a cartridge housing (not shown) that, with the diaphragm of speaker 120, defines the front and rear chambers of speaker 120. In some embodiments, the open ended headset 100 may also include a power supply 130. The power source 130 may be located at any location on the open earphone 100, for example, a location on the housing 110 that is remote or near the speaker 120. In some embodiments, the position of the power supply 130 may be set reasonably according to the weight distribution of the open earphone 100, so that the weight distribution on the open earphone 100 is balanced, thereby improving the comfort and stability of wearing the open earphone 100 by the user. In some embodiments, power supply 130 may provide power to various components of open earphone 100 (e.g., speaker 120, movement 121, etc.). Power supply 130 may be electrically connected to speaker 120 and/or movement 121 to provide electrical power thereto. It is known that when the diaphragm is vibrating, the front and rear sides of the diaphragm can simultaneously produce a set of sounds having a phase difference. After passing through the front and rear chambers 113 and 114, respectively, sound propagates outward from the positions of the hole portions 111 and 112. In some embodiments, the sound output from the speaker 120 at the hole parts 111 and 112 may satisfy a specific condition by providing the structures of the front and rear chambers 113 and 114. For example, the lengths of the front and rear chambers 113 and 114 may be designed such that a set of sounds having a specific phase relationship (e.g., opposite phases) may be output at the hole portions 111 and 112, so that both the listening volume of the near field of the open earphone 100 is small and the problem of leakage in the far field is effectively improved.

In order to further explain the influence of the distribution of the hole portions on both sides of the auricle on the sound output effect of the open earphone, the open earphone and the auricle are equivalent to a model of a dual sound source-baffle in this specification.

For convenience of description and illustration only, when the hole size on the open earphone is small, each hole may be approximately regarded as one point sound source. Sound-field sound pressure p generated by a single-point sound source satisfies the formula (1):

wherein ω is angular frequency ρ ₀ Is air density, r is distance between target point and sound source, Q ₀ The sound field sound pressure of the point sound source is inversely proportional to the distance from the point sound source, where k is the wave number.

As described above, the sound radiated to the surrounding environment (i.e., far-field leakage sound) of the open earphone can be reduced by providing two hole portions (e.g., hole portion 111 hole portion 112) in the open earphone 100 to configure the dipole sound source. In some embodiments, the two hole portions, i.e., the dipole sound source, output sounds with a certain phase difference. When the position, the phase difference, etc. between the dipole sound sources satisfy certain conditions, the open earphone can be made to exhibit different sound effects in the near field and the far field. For example, when the phases of the point sound sources corresponding to the two hole portions are opposite, that is, the absolute value of the phase difference between the two point sound sources is 180 °, the reduction of far-field leakage sound can be achieved according to the principle of the acoustic wave anti-phase cancellation. For another example, when the phases of the point sound sources corresponding to the two hole portions are approximately opposite, the far-field leakage sound can be reduced. By way of example only, the absolute value of the phase difference between two point sound sources that achieve far-field leakage reduction may be in the range of 120 ° -240 °.

Fig. 2 is a schematic diagram of two point sound sources provided according to some embodiments of the present description.

As shown in fig. 2, sound field sound pressure p generated by the dipole sound source satisfies the following formula:

wherein A1 and A2 are the intensities of two point sound sources respectively,for the phase of the point sources, d is the spacing between two point sources, r ₁ And r ₁ Satisfy formula (3):

wherein r is the distance between any target point in space and the center of the dipole sound source, and θ represents the included angle between the line connecting the target point and the center of the dipole sound source and the straight line where the dipole sound source is located.

As can be seen from the formula (3), the sound pressure p of the target point in the sound field is related to the sound source intensity, the distance d, the phase, and the distance from the sound source.

Fig. 3 is a schematic diagram of two point sound sources and listening positions provided in accordance with some embodiments of the present description. Fig. 4 is a frequency response plot of dipole sound sources of different spacing at near-field listening locations provided in accordance with some embodiments of the present disclosure.

In this embodiment, the listening position is used as the target point, so as to further describe the relationship between the sound pressure at the target point and the distance d between the point sound sources. The listening position referred to herein may be used to represent the position of the user's ear, i.e. the sound at the listening position may be used to represent near-field sound produced by two point sound sources. It is to be noted that "near-field sound" means a sound within a certain range from a sound source (e.g., a point sound source equivalent to the hole portion 111), for example, a sound within a range of 0.2m from the sound source. As an exemplary illustration only, as shown in fig. 3, the point sound source A1 and the point sound source A2 are located on the same side of the listening position, and the point sound source A1 is closer to the listening position, and the point sound source A1 and the point sound source A2 output sounds having the same magnitude but opposite phases, respectively. As shown in fig. 4, as the distance between the point sound source A1 and the point sound source A2 gradually increases (for example, from d to 10 d), the volume of the listening position gradually increases. This is because as the distance between the point sound source A1 and the point sound source A2 increases, the difference in the amplitude of the two sounds reaching the listening position (i.e., the sound pressure difference) becomes larger, the difference in the sound path becomes larger, the effect of canceling the sound becomes weaker, and the volume of the listening position increases. However, since the situation of sound cancellation still exists, the volume at the listening position is still smaller at the middle and low frequency band (for example, the sound with the frequency less than 1000 Hz) than the volume generated by the single-point sound source with the same intensity at the same position. But in a high frequency band (e.g., sound with a frequency close to 10000 Hz), due to the reduction of the wavelength of sound, a condition that the sound mutually enhances is satisfied, so that the sound generated by the dipole sound source is larger than that of the single-point sound source. In the embodiment of the present specification, the sound pressure amplitude, that is, the sound pressure, may refer to the pressure of sound generated by vibration of air.

In some embodiments, the volume at the listening position may be increased by increasing the spacing of the dipole sound sources, but as the spacing increases, the ability of the dipole sound sources to cancel sound becomes weaker, resulting in an increase in far field leakage. By way of illustration only, fig. 5 is a plot of leakage index at the far field for dipole sources of different spacing provided in accordance with some embodiments of the present disclosure. As shown in fig. 5, with the far-field leakage index of the single-point sound source as a reference, as the distance between the dipole sound sources increases from d to 10d, the leakage index of the far field gradually increases, indicating that the leakage gradually increases. For details on the leakage index, reference is made to formula (4) and its related description in this specification.

In some embodiments, two hole portions in the open earphone are distributed on two sides of the auricle, which is beneficial to improving the output effect of the open earphone, namely increasing the sound intensity of the near-field listening position and reducing the volume of far-field leakage. For convenience of explanation only, the open earphone is configured such that the auricle of the human body is equivalent to a baffle plate, and the sound emitted from the two hole portions is equivalent to two point sound sources (for example, a point sound source A1 and a point sound source A2). Fig. 6 is an exemplary distribution diagram of baffles disposed between dipole sound sources provided according to some embodiments of the present disclosure. As shown in fig. 6, when a baffle is disposed between the point sound source A1 and the point sound source A2, in the near field, the sound field of the point sound source A2 needs to bypass the baffle to interfere with the sound wave of the point sound source A1 at the listening position, which is equivalent to increasing the sound path from the point sound source A2 to the listening position. Therefore, assuming that the point sound source A1 and the point sound source A2 have the same amplitude, the difference in amplitude of the sound waves of the point sound source A1 and the point sound source A2 at the listening position increases compared to the case where no baffle is provided, so that the degree to which the two paths of sound cancel at the listening position decreases, and the volume at the listening position increases. In the far field, since the sound waves generated by the point sound source A1 and the point sound source A2 can interfere in a larger space range without bypassing the baffle plate (similar to the case without the baffle plate), the leakage sound of the far field is not increased significantly compared with the case without the baffle plate. Therefore, by arranging the baffle structure between the point sound source A1 and the point sound source A2, the sound volume of the near-field sound listening position can be remarkably improved under the condition that the sound volume of the far-field sound leakage is not remarkably increased. It will be appreciated that the auricle is used herein as a baffle between two apertures to reduce leakage and increase the volume of the sound of the open earphone, and in some embodiments, a baffle may be provided between two apertures to achieve the effect of reducing leakage and increasing volume of the sound, see in particular figures 31-52 of the present specification, and their associated description.

Fig. 7 is a frequency response curve of a near field when an auricle is located between dipole sound sources provided according to some embodiments of the present specification, and fig. 8 is a frequency response curve of a far field when an auricle is located between dipole sound sources provided according to some embodiments of the present specification. In this specification, when dipole sound sources are located on both sides of the auricle, respectively, the auricle has a baffle effect, and thus, for convenience, the auricle may also be referred to as a baffle. As an exemplary illustration, due to the presence of the auricle, in the near field, the sound field of the auricle rear side point sound source needs to bypass the auricle to reach the listening position, which is equivalent to increasing the sound path of the auricle rear side point sound source to the listening position, whereas for the far field position, the sound field of the point sound source on both sides of the auricle may reach the far field position without bypassing the auricle, and thus, the result when the auricle is used as a baffle may be equivalent to that the near field sound is generated by the dipole sound source with the interval D1 (also referred to as mode 1), and the far field sound is generated by the dipole sound source with the interval D2 (also referred to as mode 2), wherein D1> D2. As shown in fig. 7, when the frequency is low (for example, when the frequency is less than 1000 Hz), the near-field sound (i.e., the sound heard by the ears of the user) when the dipole sound sources are distributed on both sides of the auricle has substantially the same volume as that of the near-field sound of mode 1, both of which are greater than that of mode 2, and are close to that of the single-point sound source. As the frequency increases (e.g., at frequencies between 2000Hz and 7000 Hz), the near-field sound volume is greater for mode 1 and dipole sources distributed on both sides of the pinna than for single point sources. This demonstrates that when the pinna of a user is located between dipole sound sources, the near-field sound volume delivered by the sound source to the user's ear can be effectively enhanced. As shown in fig. 8, the far-field leakage volume increases with increasing frequency, but when dipole sound sources are distributed on both sides of auricles, the far-field leakage volume generated by the dipole sound sources is substantially the same as that of mode 2, and is smaller than that of mode 1 and that of a single-point sound source. Therefore, when auricles of a user are positioned between dipole sound sources, the sound transmitted to a far field by the sound sources can be effectively reduced, and leakage sound emitted by the sound sources to the surrounding environment can be effectively reduced.

For specific meaning and related content of the above-mentioned leakage index, reference may be made to the following description. In open earphone applications, it is desirable to ensure that the sound pressure delivered to the listening position is large enough to meet the listening demand, while at the same time ensuring that the sound pressure of the far-field radiated sound is small enough to reduce leakage. Therefore, the leakage index α can be taken as an index for evaluating the leakage-reducing ability:

wherein P is _far Representing sound pressure of open earphone in far field (i.e., far field leakage sound pressure), P _ear Representing the sound pressure around the user's ear (i.e., near-field listening sound pressure).

As can be seen from the formula (4), the smaller the leakage index, the stronger the leakage-reducing ability of the open earphone, and the smaller the leakage in the far field when the near-field listening volume is the same at the listening position. As shown in fig. 9, when the frequency is less than 10000Hz, the leakage index of the dipole sound sources distributed on both sides of the auricle is smaller than that of the mode 1 (no baffle structure between the dipole sound sources and the interval D1), the mode 2 (no baffle structure between the dipole sound sources and the interval D2) and the single-point sound source, thereby indicating that the open earphone has better leakage reduction capability when the dipole sound sources are respectively located on both sides of the auricle.

Fig. 10 is a schematic illustration of a measurement of leakage provided in accordance with some embodiments of the present description. As shown in fig. 10, the listening position is located on the left side of the point sound source A1, and the leakage is measured by selecting, as the value of leakage, the average value of the sound pressure amplitudes of points on a spherical surface having a radius r and centered on the center of the dipole sound source (A1 and A2 shown in fig. 10). It should be understood that the method for measuring the leakage sound in the present specification is only illustrative of the principle and effect, and is not limited thereto, and the measuring and calculating modes of the leakage sound may be reasonably adjusted according to the actual situation. For example, the sound pressure amplitudes of two or more points are uniformly averaged at the far field according to a certain spatial angle with the center of the dipole sound source as the center. In some embodiments, the listening may be measured by selecting a location point near the point source as a listening position, and using a sound pressure amplitude measured at the listening position as a listening value. In some embodiments, the listening position may or may not be on the line of the two point sources. The measurement and calculation modes of the listening sound can be reasonably adjusted according to actual conditions, for example, the sound pressure amplitude of other points or more than one point of the near-field position is taken for averaging. For example, sound pressure amplitudes of two or more points are uniformly averaged in the near field with respect to a certain spatial angle around a certain point sound source. In some embodiments, the distance between the near-field listening position and the point sound source is much smaller than the distance of the point sound source from the far-field leak measurement sphere.

In order to further explain the influence of the dipole sound source or the presence or absence of a baffle between two hole portions on the sound output effect of the open earphone, the near-field sound volume and/or the far-field sound leakage volume of the listening position under different conditions will be specifically described.

Fig. 11 is a graph of frequency response between two point sound sources with or without baffles provided in accordance with some embodiments of the present description. As shown in fig. 11, after the baffle is added between two point sound sources (i.e., two hole portions), in the near field, the distance between the two point sound sources is increased, and in the near field listening position, the volume is generated by a group of dipole sound sources with larger distances, so that the listening volume of the near field is obviously increased compared with the case without the baffle. In the far field, since the interference of sound waves generated by two point sound sources is little influenced by the baffle plate, the leakage sound is generated by a group of dipole sound sources with smaller distance, and the leakage sound is not obvious under the condition of the existence/non-existence of the baffle plate. Therefore, by arranging the baffle plate between the two hole parts (dipole sound sources), the near-field volume of the sound output device can be remarkably increased while the sound leakage reduction capability of the sound output device is effectively improved. Therefore, the requirements on components playing a sound producing role in the open earphone are greatly reduced, and meanwhile, the circuit structure is simple, so that the electric loss of the open earphone can be reduced, and the service time of the open earphone can be greatly prolonged under the condition of a certain electric quantity.

Fig. 12 is a plot of sound pressure amplitude for a dipole sound source at 300Hz at different spacings provided in accordance with some embodiments of the present disclosure. Fig. 13 is a plot of sound pressure amplitude for a dipole sound source at 1000Hz at different spacings provided in accordance with some embodiments of the present disclosure. As shown in fig. 12 and 13, in the near field, when the frequency is 300Hz or 1000Hz, with the increase of the dipole sound source distance d, the volume of the sound when the baffles are present between the dipole sound sources is always larger than the volume of the sound when the baffles are not present between the dipole sound sources, which means that the baffle structure is arranged between the dipole sound sources at the frequency, so that the volume of the sound in the near field can be effectively increased. In the far field, the sound leakage volume when the baffle plates are arranged between the dipole sound sources is equivalent to that when the baffle plates are not arranged between the dipole sound sources, which shows that whether baffle plate structures are arranged between the dipole sound sources has little influence on the far-field sound leakage at the frequency.

Fig. 14 is a plot of sound pressure amplitude for a dipole sound source at 5000Hz at different spacings provided in accordance with some embodiments of the present disclosure. As shown in fig. 14, in the near field, when the frequency is 5000Hz, the volume of sound when baffles are present between the dipole sound sources is always larger than the volume of sound when no baffles are present between the dipole sound sources as the dipole sound source distance d increases. In the far field, the leakage sound volume of the dipole sound sources with the baffles and without the baffles shows fluctuation change along with the change of the distance d, but the influence of the baffle structure on the far-field leakage sound is not great as can be seen in the whole.

Fig. 15 is a near field frequency response characteristic provided according to some embodiments of the present specification when the dipole sound source spacing d is 1cm, fig. 16 is a near field frequency response characteristic provided according to some embodiments of the present specification when the dipole sound source spacing d is 2cm, fig. 17 is a near field frequency response characteristic provided according to some embodiments of the present specification when the dipole sound source spacing d is 4cm, fig. 18 is a leakage index curve of a far field provided according to some embodiments of the present specification when the dipole sound source spacing d is 1cm, fig. 19 is a leakage index curve of a far field provided according to some embodiments of the present specification when the dipole sound source spacing d is 2cm, and fig. 20 is a leakage index curve of a far field provided according to some embodiments of the present specification when the dipole sound source spacing d is 4 cm. As shown in fig. 15 to 17, for different pitches d (e.g., 1cm, 2cm, 4 cm) of the hole portions, at a certain frequency, in a near-field listening position (e.g., user's ear), the volume provided when the two hole portions are respectively disposed on both sides of the auricle (i.e., the case of "having a baffle effect" shown in the drawing) is larger than the volume provided when the two hole portions are not disposed on both sides of the auricle (i.e., the case of "having no baffle effect" shown in the drawing). The certain frequency here may be below 10000Hz, or preferably below 5000 Hz.

As shown in fig. 18 to 20, for different pitches d (for example, 1cm, 2cm, 4 cm) of the hole portions, at a certain frequency, at a far-field position (for example, an environmental position away from the user's ear), the volume of the leakage sound generated when the two hole portions are respectively disposed on both sides of the auricle is smaller than that generated when the two hole portions are not disposed on both sides of the auricle. It is to be appreciated that as the spacing of the two hole portions or dipole sound sources increases, the destructive interference of sound at far field locations may decrease, resulting in a gradual increase in far field leakage and a decrease in leakage-reducing ability. The spacing d of the two hole portions or dipole sound sources cannot be too large. In some embodiments, in order to keep the open earphone capable of outputting as loud sound as possible in the near field while suppressing leakage sound in the far field, the distance d between the two hole portions may be set to not less than 1cm and not more than 20cm. For example, the distance d between the two hole portions may be set to not less than 1cm and not more than 12cm.

In some embodiments, the location of the listening position relative to the dipole sound source has an effect on the near-field listening volume and far-field leakage reduction, with the dipole sound source spacing maintained. In order to improve the output effect of the open earphone, in some embodiments, two holes may be provided on the open earphone, and the two holes are respectively located on the front and rear sides of the auricle of the user when the user wears the earphone. In some embodiments, the acoustic path of the aperture located on the front side of the pinna from the user's ear canal (i.e., the acoustic distance of the aperture to the entrance location of the user's ear canal) is shorter than the acoustic path of the aperture located on the rear side of the pinna from the user's ear, given that sound emanating from the aperture located on the rear side of the pinna needs to bypass the pinna to reach the user's ear canal. To further illustrate the effect of listening positions on sound output, as an exemplary illustration, in embodiments of the present disclosure, fig. 21A is a schematic diagram of baffle-free dipole sound sources at different listening positions in the near field, as shown in fig. 21A, where four representative listening positions (listening position 1, listening position 2, listening position 3, listening position 4) are selected, and the effects and principles of listening position selection are illustrated. The distances between the listening position 1, the listening position 2 and the listening position 3 and the point sound source A1 are equal, r1, the distance between the listening position 4 and the point sound source A1 is r2, r2 is smaller than r1, and the point sound source A1 and the point sound source A2 respectively generate sounds with opposite phases.

Fig. 21B is a graph of various levels of baffles as shown in some embodiments of the present disclosure as a function of the ability to reduce leakage relative to listening positions in the absence of baffles. Because the baffle has an influence on the near-field listening volume mainly by changing the sound path difference from the two point sound sources to the listening position, the influence of the baffle on the near-field listening volume and the far-field leakage of the earphone is necessarily influenced by the height of the baffle. Fig. 21B shows the effect of baffles of different heights in different listening positions relative to no baffles. From the foregoing results, it can be seen that, for different listening positions, the volume of the listening position after the baffle is added is increased relative to that of the listening position without the baffle, and the sound leakage reduction capability may be increased or may be reduced. Fig. 21B only shows the change in the ability of the baffles of different heights to reduce leakage from the listening positions when the baffles are not present. "v" indicates an increase in the ability to drop sound (decrease in the leakage index), and "x" indicates a decrease in the ability to drop sound (increase in the leakage index). In listening position 1 (and nearby and axisymmetric positions), i.e. listening position very close to the baffle, baffles of different heights have the effect of enhancing the sound leakage reduction capability; in listening position 2 and listening position 4 (and nearby, and axisymmetric positions), baffles of not too great height (h/d < 2) have an effect on enhancing the sound leakage reduction; in listening position 3, the baffles with smaller height (h/d < 0.6) are effective in enhancing the sound leakage reduction capability. The baffle is inclined at an angle, and the angle change is between 15deg and 165 deg. The total length of the baffle plates is equal to the distance d between the two sound sources, and the crossed vertexes of the baffle plates are positioned at the center point of the dipole sound source. The listening position is 0.025d from the center point of the dual point sound source.

Fig. 22 is a graph of frequency response characteristics of a baffle-less dipole sound source at different listening positions in the near field, provided in accordance with some embodiments of the present disclosure. Fig. 23 is a graph of leakage index of a baffle-free dipole sound source at different listening positions in the near field, provided in accordance with some embodiments of the present disclosure. As shown in fig. 22 and 23, for listening position 1, since the difference in sound path between point sound source A1 and point sound source A2 at listening position 1 is small, the difference in amplitude of the sound generated by the two point sound sources at listening position 1 is small, so that the sound of the two point sound sources after the listening position 1 interferes results in a smaller listening volume than the other listening positions. For listening position 2, the distance between the listening position and point sound source A1 is unchanged compared with listening position 1, i.e. the sound interval from point sound source A1 to listening position 2 is unchanged, but the distance between listening position 2 and point sound source A2 is increased, the sound interval from point sound source A2 to listening position 2 is increased, the difference in amplitude of the sound generated by point sound source A1 and point sound source A2 at this position is increased, so the volume of the sound of the two point sound sources after the interference at listening position 2 is greater than the volume of the sound at listening position 1. Since the difference in sound ranges from the point sound source A1 and the point sound source A2 to the listening position 3 is largest in all the circular arc positions with the radius r1, the volume of listening at the listening position 3 is largest compared to the listening position 1 and the listening position 2. With respect to the listening position 4, since the distance between the listening position 4 and the point sound source A1 is small, the sound amplitude of the point sound source A1 at this position is large, so the listening volume of this listening position is large. In summary, the volume of the near-field listening position varies with the relative position of the listening position and the two point sources. When the listening position is on the line of two point sound sources and is on the same side of the two point sound sources (for example, listening position 3), the difference in sound path between the two point sound sources is largest at the listening position (the difference in sound path is the distance d between the two point sound sources), and in this case (i.e., when the auricle does not act as a baffle), the listening volume at this listening position is larger than that at other positions. According to the formula (4), under the condition that far-field leakage sound is certain, the leakage sound index corresponding to the listening position is minimum, and the leakage sound reducing capability is strongest. Meanwhile, by reducing the distance r1 between the listening position and the point sound source A1 (for example, listening position 4), the volume of the listening position can be further increased, and meanwhile, the leakage index is reduced, so that the leakage reduction capability is improved.

Fig. 24 is a graph of frequency response of a baffle dipole sound source (as in the case of fig. 21A) at different listening positions in the near field, and fig. 25 is a graph of leakage index at different listening positions based on fig. 24 and calculated according to equation (4), according to some embodiments of the present disclosure. As shown in fig. 23 and 24, the volume of the sound produced by the dipole sound source at listening position 1 increases significantly with the baffle relative to the non-baffle case, and the volume of the sound at listening position 1 exceeds the volumes of the sound at listening positions 2 and 3. This is because, after adding the baffle between the two point sound sources, the sound path of the point sound source A2 reaching the listening position 1 increases, resulting in a significant increase in the difference in sound path of the two point sound sources reaching the listening position 1, and the difference in amplitude of the sound generated by the two point sound sources at the listening position 1 increases, so that interference cancellation of the sound is not likely to occur, resulting in a significant increase in the volume of the sound generated at the listening position 1. In the listening position 4, since the distance between the listening position and the point sound source A1 is further reduced, the sound amplitude of the point sound source A1 at this position is large, and the listening volume of the listening position 4 is still the largest among the 4 listening positions taken. For listening position 2 and listening position 3, the sound path increasing effect of the baffle on the sound field of point sound source A2 reaching these two listening positions is not obvious, so the sound volume increasing effect at listening position 2 and listening position 3 is smaller than that at listening position 1 and listening position 4 closer to the baffle.

Since the leakage volume of the far field does not change with the change of the listening position, and the listening volume of the near field listening position changes with the change of the listening position, the leakage index of the open earphone is different according to formula (4) at different listening positions. Wherein, the listening positions with larger listening volume (for example, listening position 1 and listening position 4) have small leakage indexes and strong leakage reducing capability; listening positions with smaller listening volume (e.g., listening position 2 and listening position 3) have larger leakage indexes and weaker leakage reduction capability.

Therefore, according to the practical application scene of the open earphone, the auricle of the user can be used as a baffle, two holes on the open earphone are respectively arranged at the front side and the rear side of the auricle, and the auditory canal is arranged between the two holes as an auditory position. In some embodiments, by designing the positions of the two hole portions on the open earphone such that the distance from the hole portion on the front side of the auricle to the ear canal is smaller than the distance from the hole portion on the rear side of the auricle to the ear canal, at this time, since the distance from the hole portion on the front side of the auricle to the ear canal is closer, the amplitude of sound generated at the ear canal by the hole portion on the front side of the auricle is larger, and the amplitude of sound generated at the ear canal by the hole portion on the rear side of the auricle is smaller, interference cancellation of sound at the ear canal by the two hole portions is avoided, thereby ensuring that the volume of listening sound at the ear canal is larger.

Fig. 26 is an exemplary distribution diagram of two hole portions and pinna provided according to some embodiments of the present description. In some embodiments, the position of the pinna (also referred to as baffle in fig. 26-29) between the two aperture portions (i.e., point sources) also has some effect on the output of sound. As an exemplary illustration only, as shown in fig. 26, a baffle is provided between the point sound source A1 and the point sound source A2, the listening position is located on the line connecting the point sound source A1 and the point sound source A2, and the listening position is located between the point sound source A1 and the baffle, the distance between the point sound source A1 and the baffle is L, the distance between the point sound source A1 and the point sound source A2 is d, the distance between the point sound source A1 and the listening is L1, and the distance between the listening position and the baffle is L2. When the distance L1 between the listening position and the point sound source A1 is unchanged, the positions of the baffles (corresponding to the movement of the two hole parts relative to the auricle) are moved, so that the distance L between the point sound source A1 and the baffles and the distance d between the dipole sound sources have different proportional relations, and the listening volume and the far-field leakage volume of the listening position under the different proportional relations can be obtained.

Fig. 27 is a frequency response curve of a near field at different positions of a baffle provided according to some embodiments of the present disclosure, fig. 28 is a frequency response curve of a far field at different positions of a baffle provided according to some embodiments of the present disclosure, and fig. 29 is a plot of a leakage index at different positions of a baffle provided according to some embodiments of the present disclosure. In connection with fig. 26 to 29, the leakage sound of the far field varies little with the position of the baffle between dipole sound sources. When the distance d between the point sound source A1 and the point sound source A2 is kept unchanged, and when L is reduced, the volume of the listening position is increased, the leakage index is reduced, and the leakage-reducing capability is enhanced; when L increases, the volume of the listening position increases, the leakage index increases, and the leakage reducing capability decreases. The reason for this is that when L is small, the listening position is closer to the baffle plate, which increases the sound path of the sound wave of the point sound source A2 propagating to the listening position, thereby increasing the sound path difference of the point sound source A1 and the point sound source A2 reaching the listening position, reducing interference cancellation of the sound, so that the volume increase of the listening position after adding the baffle plate is larger. When L is large, the listening position is far from the baffle, and the influence of the baffle on the difference in sound path between the point sound source A1 and the point sound source A2 to the listening position is small, so that the volume change of the listening position after adding the baffle is small.

From the above, by designing the position of the upper hole of the open earphone, when the user wears the open earphone, the auricle of the user is used as a baffle to separate different hole parts, so that the structure of the open earphone is simplified, and the output effect of the open earphone can be further improved. In some embodiments, to ensure the sound leakage reduction capability of the open earphone, the positions of the two hole portions may be designed such that the ratio of the distance of the hole portion on the front side of the auricle to the auricle (or the contact point on the open earphone for contact with the auricle) to the interval between the two hole portions is not more than 0.5 when the open earphone is worn by the user.

It is to be appreciated that the sound path from the speaker to the aperture in an open earphone has some effect on near-field volume and far-field leakage. The sound path can be changed by adjusting the length of the cavity between the diaphragm and the aperture in the open earphone. In some embodiments, the speaker includes a diaphragm, and front and rear sides of the diaphragm are coupled to the two aperture portions through the front and rear chambers, respectively. The sound path from the diaphragm in the two hole parts to the two hole parts is different. In some embodiments, the diaphragm to two apertures sound Cheng Bi is 0.5-2 in order to increase near field volume and reduce far field leakage.

In some embodiments, the amplitude of the sound generated at the two hole portions may be changed to improve the output effect of the open earphone while maintaining opposite phases of the sound generated at the two hole portions. Specifically, the purpose of adjusting the sound amplitude at the aperture may be achieved by adjusting the impedance of the acoustic path between the two apertures and the speaker. In some embodiments, the structure between the two hole portions of the speaker may have different sound impedances so that sounds respectively output from the two hole portions by the speaker have different sound pressure magnitudes. In embodiments of the present description, impedance may refer to the resistance that the displacement of the medium needs to overcome when conducting sound waves. The acoustic path may or may not be filled with damping material (e.g., tuning mesh, tuning cotton, etc.) to effect amplitude modulation of the sound. For example, in some embodiments, a resonant cavity, an acoustic port, an acoustic slot, a tuning mesh, or tuning cotton may be provided in the acoustic path to adjust the acoustic resistance to change the impedance of the acoustic path. For another example, in some embodiments, the acoustic resistance of the acoustic path may also be varied by adjusting the apertures of the two hole portions. Preferably, the ratio of the acoustic impedances of (the diaphragm of) the loudspeaker to the two hole portions is 0.5-2.

In some embodiments, the acoustic path through which sound generated by the speaker (or diaphragm) radiates to the external environment may be used as an acoustic transmission structure for an open earphone. The acoustic transmission structure may have a resonant frequency around which the acoustic transmission structure may resonate, which may alter the frequency content of the transmitted sound (e.g., add additional resonance peaks to the transmitted sound), or alter the phase of the transmitted sound in the acoustic transmission structure, which may attenuate the effects of cancellation of the sound at far-field interference, and even increase far-field leakage around the resonant frequency.

In some embodiments, the open earphone may include a filtering structure that may have a modulating effect on the frequency characteristics of the sound waves. For example, the filtering structure may include a sound absorbing structure for absorbing sound transmitted in the acoustic transmission structure within a target frequency range. The target frequency range may include a resonant frequency of the acoustic transmission structure. By way of example only, a filtering structure (or sound absorbing structure) may be disposed in the acoustic transmission structure between the aperture portion farther from the ear canal orifice and the speaker to absorb sound transmitted therein near the resonant frequency, avoiding resonance peaks that are increased by resonance of the acoustic transmission structure and/or phase changes that occur to increase leakage sound in the far field. In some embodiments, the resonant frequency of the acoustic transmission structure may be in the mid-high frequency range (e.g., 1kHz-10 kHz). In a high frequency range larger than the resonance frequency, since the wavelength of the high frequency sound is short, the distance between the two hole portions may affect the phase difference of the sound radiated from the two hole portions in the far field, thereby causing the sound leakage reducing effect of the dipole sound source formed by the two hole portions in the high frequency range to be weakened. Thus, the target frequency range may include a frequency greater than the resonance frequency of the acoustic transmission structure, so that high frequency sound may be absorbed, improving leakage of the dipole sound source in the high frequency range. And for frequencies outside the target frequency range, for example, frequencies smaller than the resonance frequency, the dipole sound source formed by the two hole parts can realize better sound leakage reduction effect. For more description of the filtering structure, see fig. 75-86 and their associated description, which are not repeated here.

It should be appreciated that the above description of the filtering structure and the target frequency range does not limit the actual usage scenario of the open earphone. In some embodiments, the open headphones may be provided with different sound effects at points in space by providing filtering structures (e.g., locations of filtering structures, sound absorption frequencies, etc.). For example, the filtering structure may absorb middle-high frequency sound in a specific frequency range, and the acoustic transmission structure is disposed between the near-ear hole portion and the speaker, so as to reduce middle-high frequency sound in the specific frequency range output from the near-ear hole portion, and avoid interference enhancement of middle-high frequency sound in the specific frequency range and middle-high frequency sound in the same frequency range output from the far-ear hole portion in the far field. As another example, the filtering structure may absorb middle-high frequency sounds in a specific frequency range, and be respectively disposed in the transmission structure between the speaker and the near-earhole portion and the far-earhole portion, so as to better reduce leakage of the middle-high frequency sounds in the specific frequency range in the far field. For another example, the filtering structure may absorb low frequency sound in a specific frequency range, and be disposed in the acoustic transmission structure between the speaker and the far earhole portion, so as to reduce the low frequency sound in the specific frequency range output from the far earhole portion, avoid interference cancellation between the low frequency sound in the specific frequency range and the low frequency sound in the same frequency range output from the near earhole portion in the near field, and thereby increase the volume of the open earphone in the near field (i.e., transmitted to the user's ear) in the specific frequency range. For another example, the filtering structure may further include sub-filtering structures that absorb different frequency ranges, for example, the middle and high frequency bands and the low frequency band, respectively, for absorbing sounds of the different frequency ranges.

It should be appreciated that the above description (fig. 1-29) is not limiting of the actual use scenario of the open earphone. The open earphone may be any device or part thereof that requires sound output to the user. For example, the open earphone may be applied in a mobile phone. Fig. 30 is a schematic diagram of a cell phone having a hole portion according to some embodiments of the present disclosure. As shown, the top 3020 of the handset 3000 (i.e., the top surface "perpendicular" to the handset display) is provided with a plurality of holes. By way of example only, the aperture portion 3001 may constitute a set of dipole sound sources (or point sound source array) for outputting sound. One of the holes 3001 may be near the left end of the top 3020 and the other hole may be near the right end of the top 3020, with a distance between the two holes. A speaker 3030 is provided inside the housing of the mobile phone 3000. Sound generated by the speaker 3030 can be transmitted outward through the hole portion 3001.

In some embodiments, two apertures 3001 may emit a set of sounds of opposite (or approximately opposite) phase, identical (or approximately identical) amplitude. When the user places the mobile phone near the ear to answer the voice information, the hole 3001 may be respectively located at two sides of the user's ear, which is equivalent to adding the difference between the sound ranges from the two hole portions to the user's ear according to the embodiments described in fig. 1-29, so that the hole 3001 may emit stronger near-field sound to the user. Meanwhile, the influence of the user's ear on the sound radiated in the far field by the hole portion 3001 is small, so that the hole portion 3001 can reduce leakage sound to the surrounding environment due to interference cancellation of the sound. Further, the hole part is formed in the top of the mobile phone, but not in the upper end of the front display screen of the mobile phone, so that the space required by the hole part arranged in the front of the mobile phone can be saved, the area of the front display screen of the mobile phone can be further increased, and the appearance of the mobile phone can be more concise and attractive.

In some embodiments, the two aperture portions of the open earphone may also be located on the same side of the user's pinna. A baffle is arranged between the two hole parts, and the baffle can increase the sound path from one of the two hole parts to the ears of the user.

In some embodiments, the two aperture portions may include a first aperture portion and a second aperture portion, and the first aperture portion may have a smaller acoustic path to the user's ear than the second aperture portion. The first hole portion and the second hole portion may be located on the same side of the auricle of the user, respectively, and a baffle may be disposed between the first hole portion and the second hole portion, and the baffle increases the sound path from the second hole portion to the ear of the user. In some embodiments, the first and second aperture portions may be located on the anterior side of the user's pinna, such as aperture portions 3111 and 3112, respectively.

Fig. 31 is an exemplary block diagram of an open earphone according to some embodiments of the present description. The structure of the open earphone 3100 shown in fig. 31 is substantially the same as that of the open earphone 100 shown in fig. 1, and for example, the open earphone 3100 includes a housing 3110 and a speaker 3120. The housing 3110 is configured to carry the speaker 3120 and has two aperture portions 3111 and 3112 in acoustic communication with the speaker 3120. Inside the case 3110, a movement 3121 and a main board 3122 are provided, and the movement 3121 may constitute at least part of the structure of the speaker 3120, and the speaker 3120 can generate sound using the movement 3121. Motherboard 3122 may be electrically connected to movement 3121 to control sounding of movement 3121. As another example, the open earphone 3100 may also include a power supply 3140, and the power supply 3140 may provide power to various components of the open earphone 3100 (e.g., the speaker 3120, the movement 3121, etc.). The speaker 3120 may include a diaphragm, a front side of which is provided with a front chamber 3113 for transmitting sound. The front chamber 3113 is acoustically coupled to the aperture 3111, and sound at the front side of the diaphragm can be emitted from the aperture 3111 through the front chamber 3113. A rear chamber 3114 for transmitting sound is provided at a position of the rear side of the diaphragm. The rear chamber 3114 is acoustically coupled to the aperture 3112, and sound at the rear side of the diaphragm can be emitted from the aperture 3112 through the rear chamber 3114. The difference is that when the user wears the open earphone 3100, the housing 3110 has two hole portions (hole portion 3111 and hole portion 3112) located on the front side of the auricle of the user, and a baffle 3130 is provided between the two hole portions.

Referring to fig. 31, the hole portions 3111 and 3112 may be located at both sides of the baffle 3130, respectively. The baffle 3130 forms a certain angle θ with the line connecting the hole 3111 and the hole 3112. In this case, the baffle 3130 may be used to adjust the distance of the aperture 3111 and the aperture 3112 from the user's ear (i.e., listening position). In some embodiments, a first of the two apertures (e.g., aperture 3111) may be located on one side of baffle 3130 with the user's ear, and a second aperture (e.g., aperture 3112) is located on the other side of baffle 3130, with the first aperture to the user's ear being less acoustic than the second aperture to the user's ear. The hole portion and the ear of the user are positioned on one side of the baffle plate, and the hole portion and the ear canal opening are positioned on one side of the baffle plate.

The number of baffles 3130 may be one or more. For example, one or more baffles 3130 may be provided between the aperture 3111 and the aperture 3112. As another example, when the open earphone 3100 further includes a hole portion other than the hole portion 3111 and the hole portion 3112, one or more baffle plates 3130 may be provided between each two hole portions (see fig. 49-52 and the related description). In some embodiments, the baffle 3130 may be fixedly connected to the housing 3110. For example, the baffle 3130 may be part of the housing 3110 or integrally formed with the housing 3110.

The arrangement of the hole portions 3111 and 3112 on both sides of the baffle 3130 is similar to the principle of the arrangement of the two hole portions on both sides of the auricle described above and the influence on the sound output effect of the open earphone, and specific reference may be made to the foregoing description, and the description is omitted here. The influence of the structural parameters of the baffle 3130 on the sound output effect of the open earphone 3100 is described below.

In some embodiments, the size of the included angle formed by the baffle and the connection line of the two hole parts (i.e. the dipole sound source) can influence the near-field listening volume of the open earphone and the far-field leakage volume. In order to further explain the influence of the included angle formed by the connecting line of the baffle plate and the two hole parts on the sound output effect, the near-field volume or/and the far-field leakage volume of the listening position under different conditions are specifically described. Fig. 32 is a schematic distribution diagram of baffles with different tilt angles between dipole sound sources according to some embodiments of the present disclosure. For illustrative purposes only, as shown in FIG. 32, the baffle is a plate structure of V-shaped configuration, the baffle being located at point source A ₁ Sum point sound source A ₂ Wherein the total length of the baffle plate is equal to the distance between the two point sound sources, and the intersection point of the connecting line of the baffle plate and the dipole sound source is positioned at the center point of the dipole sound source. In the present embodiment, a baffle plate and a dipole sound source (point sound source a ₁ Point sound source A ₂ ) The angle of the included angle θ formed by the lines may vary from 15 ° to 165 °. It should be noted that the listening position, the structure of the baffle, and the angle formed by the baffle and the dipole sound source connection line in this embodiment are merely illustrative of the principles and effects, and are not limited thereto. The listening position can be reasonably adjusted according to actual conditions.

Fig. 33 is a frequency response characteristic of the dipole sound source in the near field when the baffle of different tilt angles is employed in fig. 32. As shown in fig. 33, in the near-field listening position, the baffle forms an arbitrary angle θ (i.e., "theta" as shown in the figure) with the dipole sound source, and the volume is larger than that provided when no baffle is provided between the two hole portions (i.e., "no baffle" as shown in the figure). Therefore, the baffle plates are arranged between the dipole sound sources, so that the near-field listening volume can be effectively improved. Further, the volume of the listening sound varies significantly with the angle θ. Within a certain range, the smaller the included angle theta is, the larger the volume of the listening position is. The certain range may be 150 ° or less. Fig. 34 is a frequency response curve of the dipole sound source in the far field when the baffles of different tilt angles are employed in fig. 32. As shown in fig. 34, it can be seen that the angle formed by the connection line between the baffle plate and the dipole sound source has little influence on far-field leakage. Fig. 35 is a plot of the leakage index generated in accordance with fig. 32 and 33. As shown in fig. 35, the leakage index is smaller when the baffle plate and the dipole sound source are connected to form any included angle θ than when no baffle plate is arranged between the dipole sound sources. It can be stated that the placement of the baffles between the dipole sound sources effectively reduces the leakage index of the dipole sound sources, and that the leakage index varies significantly with the change in the spatial positional relationship between the baffles and the dipole sound sources (e.g., the above-described angle θ). The smaller the included angle theta, the smaller the leakage index, i.e. the stronger the leakage-reducing ability of the dipole sound source, within a certain range. In some embodiments, a baffle may be disposed between two hole portions of the open earphone, and an included angle formed by the baffle and a straight line where the two hole portions (i.e., the dipole sound source) are located may be reasonably designed, so that the open earphone device has high leakage-reducing capability. In embodiments of the present description, the included angle may refer to an included angle between a vector directed from an intersection point of the baffle and the line of the dipole sound source to a point sound source near the listening position and a vector directed to the outside (e.g., the surrounding environment) along a straight line where the baffle is located. In some embodiments, to ensure near-field volume of the dipole sound source and reduce far-field leakage, the baffle forms an angle with the line connecting the two apertures of less than 150 °. Preferably, in order to further ensure the near-field volume of the dipole sound source and reduce the far-field leakage, the included angle formed by the connecting line of the baffle plate and the two hole parts is not more than 90 degrees.

In some embodiments, the size of the baffle also affects the sound output effect of the dipole sound source. Fig. 36 is an exemplary distribution diagram of dipole sound sources and baffles provided according to some embodiments of the present disclosure. As an exemplary illustration only, as shown in fig. 36, at point sound source a ₁ Sum point sound source A ₂ A baffle is arranged at the central position between the two, and the listening position (such as the earhole of the user) is positioned at the point sound source A ₁ Sum point sound source A ₂ And listening position is located on the line of point sound source A ₁ Between the baffle plate and the point sound source A ₁ The distance between the baffle plate and the point sound source A is L ₁ And point sound source A ₂ The distance between the two is d, and the point sound source A ₁ The distance between the sound receiving device and the listening sound is L ₁ The distance between the listening position and the baffle plate is L ₂ The height of the baffle plate is H, the height H is perpendicular to the connecting line of the dipole sound source, and the distance from the center of the baffle plate to the connecting line of the two point sound sources is H. When the dipole sound source distance d is unchanged, the height h of the baffle plate is changed, so that the height h of the baffle plate and the dipole sound source distance d have different proportional relations, and the listening volume and the far-field leakage volume of the listening position under the different proportional relations can be obtained.

Fig. 37 is a frequency response curve of the near field of the dipole sound source when baffles of different heights are selected in the structure shown in fig. 36. As shown in fig. 37, in the listening position of the near field, the volume provided when the baffles of different heights are provided between the dipole sound sources (i.e., the case of "h/d" shown in the drawing) is larger than the volume provided when no baffle is provided between the two hole portions (i.e., the case of "no baffle" shown in the drawing). Further, as the baffle height increases, i.e., the ratio of baffle height to dipole sound source spacing increases, the volume provided by the dipole sound source at the listening position also gradually increases. It can be stated that increasing the height of the baffle appropriately can effectively increase the volume of the listening position.

Fig. 38 is a frequency response curve of the far field of the dipole sound source when baffles of different heights are selected in the structure shown in fig. 36. As shown in fig. 38, in a far field position (e.g., an environmental position away from the user's ear), when the ratio h/d of the baffle height to the dipole sound source spacing varies within a certain range (e.g., h/d is equal to 0.2, 0.6, 1.0, 1.4, 1.8 as shown), the volume of the leakage sound generated by the dipole sound source does not differ much from the volume of the leakage sound generated by the dipole sound source without the baffle. And as the ratio h/d of the baffle height to the interval of the dipole sound source increases to a certain amount (for example, h/d=5.0), the leakage sound volume of the dipole sound source at the far-field position is higher than that generated by the dipole sound source without the baffle. Therefore, in order to avoid the generation of a large leakage sound in the far field, the baffle height between dipole sound sources should not be excessively large. In some embodiments, the ratio between the spacing between the two hole portions (i.e., the above-described dipole sound source spacing) and the height of the baffle may be not less than 0.2.

Fig. 39 is a graph showing the leakage index of the dipole sound source when baffles of different heights are selected in the structure shown in fig. 36. As shown in fig. 39, the leakage index is smaller when baffles of different heights are provided between dipole sound sources than when no baffles are provided between dipole sound sources. Thus, in some embodiments, in order to keep the open earphone outputting as loud sound as possible in the near field while suppressing leakage in the far field, a baffle may be provided between the two hole portions with the ratio of the baffle height to the spacing between the two hole portions being no greater than 5. For example, the ratio of the baffle height to the spacing between the two hole portions may be no greater than 1.8. In some embodiments, the ratio between the spacing between the two hole portions and the height of the baffle plate may be no greater than 4.

In some embodiments, the two aperture portions of the open earphone may also be located on the same side of the listening position at the same time. As shown in fig. 40A, two hole portions of an open earphone (e.g., point sound source a ₁ Sum point sound source A ₂ ) May be located simultaneously below the listening position (e.g., the user's earhole). As another example, as shown in fig. 40B, two hole portions of an open earphone may be located in front of a listening position at the same time. It should be noted that the two hole portions of the open earphone are not limited to being located below and in front of the listening position, but the two hole portions may also be located in other orientations of the listening position, for example, above, etc.

When two hole parts of the open earphone are simultaneously positioned on one side of a listening position and the distance between the two hole parts is constant, when the hole part close to the listening position is closer to the listening position, the generated sound amplitude is larger, and the hole part on the other side of the baffle plate is smaller in the listening position, interference cancellation is less between the two hole parts, so that the listening volume at the listening position is ensured to be larger. In some embodiments, to increase near-field listening volume, the ratio of the distance of the hole near the listening position to the distance of the two holes may be no greater than 3.

When two hole parts of the open earphone are simultaneously positioned at one side of the listening position and the distance between the two hole parts is constant, the height of the baffle plate can influence the near-field listening volume and the far-field leaking volume of the open earphone. In some embodiments, the height of the baffle may be no greater than the spacing between the two aperture portions. For example, the ratio of the height of the baffle plate to the spacing between the two hole portions may be not more than 2.

When the listening position is fixed and the dipole sound source position is fixed, the distance from the center of the baffle to the dipole sound source connecting line also affects the near-field sound volume and the far-field sound leakage volume of the open earphone. Returning to fig. 36, the height of the baffle is H, and the distance from the center of the baffle to the line connecting the two point sound sources is H. When the distance d between the dipole sound sources is unchanged, the distance H between the center of the baffle and the connecting line of the two point sound sources is changed, so that the distance H between the center of the baffle and the connecting line of the two point sound sources and the height H of the baffle have different proportional relations, and the listening volume and the far-field leakage volume of the listening position under the different proportional relations can be obtained. In some embodiments, the center of the baffle may refer to the centroid or centroid of the baffle.

Fig. 41 is a frequency response characteristic of the near field of the dipole sound source when the ratio of the distance from the center of the baffle to the line connecting the dipole sound sources to the height of the baffle takes different values in the structure of fig. 36. As shown in fig. 41, in the listening position of the near field, the volume provided when the baffles at different positions are provided between the dipole sound sources (i.e., the case of "H/H" shown in the figure) is larger than the volume provided when no baffle is provided between the dipole sound sources (i.e., the case of "no baffle" shown in the figure). Further, as the distance between the center of the baffle and the dipole sound source increases, the volume at the near-field listening position also decreases. This is because, when the center of the baffle is away from the dipole sound source connection, the baffle weakens the blocking effect of the sound from the dipole sound source to the listening position, so that the degree of interference cancellation of the sound of the dipole sound source at the listening position becomes large, resulting in a decrease in the volume of the listening position. Fig. 42 is a frequency response curve of the far field of the dipole sound source when the ratio of the distance of the baffle center to the dipole sound source line to the baffle height takes different values in the structure of fig. 36. In the far field position, the volume of the leakage sound generated when the baffles with different positions are arranged between the dipole sound sources is not much different from the volume of the leakage sound generated when the baffles are not arranged between the dipole sound sources. Fig. 43 is a graph of the leakage index when the ratio of the distance from the center of the baffle to the line connecting the dipole sound sources to the height of the baffle is different in the structure of fig. 36. As shown in fig. 43, the leakage index is smaller when baffles with different positions are provided between the dipole sound sources (i.e., in the case of different "H/H" shown in the figure) than when no baffle is provided between the dipole sound sources (i.e., in the case of "no baffle" shown in the figure), indicating that the leakage reduction capability is stronger when baffles with different positions are provided between the dipole sound sources. Further, as the center of the baffle gradually approaches, that is, as the connecting line distance between the center of the baffle and the dipole sound source gradually decreases, the leakage index gradually decreases, and the leakage reduction capability is continuously enhanced. In some embodiments, to keep the open earphone outputting as loud sound as possible in the near field while suppressing leakage in the far field, the ratio of the distance from the center of the baffle to the line of the two apertures to the height of the baffle may be no greater than 2.

The material selected for the baffle also affects the near field volume and far field leakage volume of the open earphone. In some embodiments, the baffle may be made of an acoustically resistive material that dampens/absorbs sound at a particular frequency. For example, if it is necessary to reduce the volume of the high-frequency sound at the near-field position, it is necessary to cancel interference of the high-frequency sound at the near-field position, that is, to enable the sounds emitted from the two hole portions located on both sides of the baffle plate, which are opposite in phase, to reach the near-field position. To this end, the baffle may be made of a material that blocks low frequencies and high frequencies. In this way, the baffle plate is weak in blocking high-frequency sound, and the high-frequency sound emitted from the two side holes of the baffle plate can generate sound with close amplitude but opposite phase at the listening position, so that interference cancellation of the high-frequency sound can be restrained. The low-pass high-frequency blocking material may refer to a material having a large impedance to low-frequency sound but a small impedance to high-frequency sound. In some embodiments, the low frequency pass high frequency blocking material may include a resonant sound absorbing material, a polymeric particle sound absorbing material, or the like. For another example, to reduce the low frequency sound at near field locations, the baffle may be made of a high frequency pass-blocking low frequency material. In this way, the baffle plate can make the blocking of low-frequency sound weak, the low-frequency sound emitted by the two side holes of the baffle plate can generate sound with close amplitude but opposite phase at the listening position, and the low-frequency sound can be suppressed by interference cancellation. The high-pass low-frequency blocking material may refer to a material having a large impedance to high-frequency sound and a small impedance to low-frequency sound. In some embodiments, the high frequency pass low frequency blocking material may include a porous sound absorbing material such as foam or fiber. It should be noted that the acoustic resistance material is not limited to the above-mentioned low-pass high-frequency resistance material and high-pass low-frequency resistance material, and different acoustic resistance materials may be adopted in the open earphone according to the requirements for the acoustic frequency band.

To further illustrate the effect of the acoustic resistive material of the baffle on the output of the open earphone, a low frequency acoustic resistive baffle (i.e., a baffle made of a material having a relatively high impedance for low frequency sound and a relatively low impedance for high frequency sound) is taken as an example to specifically illustrate the near field volume and/or far field leakage volume at the listening position.

Fig. 44 is a frequency response curve of a near field when a low frequency acoustic impedance baffle is positioned between dipole sound sources, provided in accordance with some embodiments of the present disclosure. As shown in fig. 44, in the near field, in a certain frequency range (for example, 20Hz-1000 Hz), the volume of the sound when a normal baffle (i.e., a baffle made of a material having a large impedance for both low-frequency sound and high-frequency sound) and a low-frequency acoustic-resistance baffle exist between the dipole sound sources is always larger than that when no baffle exists between the dipole sound sources. When the frequency is larger than 1000Hz, the volume change of the listening sound when the low-frequency acoustic resistance baffle plate exists between the dipole sound sources and the dipole sound sources is not large, and the volume of the listening sound when the common baffle plate exists between the dipole sound sources is larger than the volume of the listening sound when the low-frequency acoustic resistance baffle plate exists between the dipole sound sources and the dipole sound sources are not provided with the baffle plates. This is because the low-frequency acoustic resistance damper has a large acoustic resistance to low-frequency sound, and when the sound emitted from the two hole portions of the open earphone is low-frequency sound, the low-frequency acoustic resistance damper can function as a damper, and interference cancellation of the sound from the two hole portions at the listening position is reduced, so that the listening volume at the listening position is ensured to be large. When the sound emitted by the two hole parts of the open earphone is high-frequency sound, the blocking effect of the low-frequency acoustic resistance baffle is weakened, and the high-frequency sound emitted by the two hole parts can be directly interfered and eliminated at the listening position through the low-frequency acoustic resistance baffle, so that the volume of the high-frequency sound generated by the open earphone at the listening position is reduced.

Fig. 45 is a frequency response curve of the far field of a low frequency acoustic resistive baffle provided in accordance with some embodiments of the present specification between dipole sound sources. As shown in fig. 45, in the far field, when the sound frequency is within a certain range (for example, the sound frequency is 20Hz-700 Hz), the leakage volume when there is a low-frequency acoustic resistance baffle or a normal baffle between the dipole sound sources and the leakage volume when there is no baffle between the dipole sound sources are not much different. With increasing frequency (for example, when the frequency is greater than 700 Hz), the volume of the leakage sound when the low-frequency acoustic resistance baffles exist between the dipole sound sources is similar to that when no baffles exist between the dipole sound sources, and the volume of the leakage sound when the low-frequency acoustic resistance baffles exist between the dipole sound sources is smaller than that when the common baffles exist between the dipole sound sources. This indicates that the leakage reduction capability of the low frequency acoustic impedance baffle between the dipole sound sources is stronger than that of the common baffle between the dipole sound sources at medium and high frequencies.

The structure of the baffle can also affect the near-field volume and far-field leakage volume of the open earphone. In some embodiments, the baffle may also be provided with a specific acoustic structure that may act on (e.g., absorb, block) or the like the passing sound to adjust the sound of the listening position, including increasing the volume of the listening position, enhancing the sound of a specific frequency band (e.g., low frequency, high frequency, etc. as referred to herein), or attenuating the sound of a specific frequency band, etc. To further explain the influence of the acoustic structure on the sound effect, description will be made below with reference to fig. 46 (a), fig. b, fig. c, and fig. d.

Fig. 46 is a schematic structural view of several acoustic structures shown in accordance with some embodiments of the present description. As shown in fig. (a), the acoustic structure 4610 may include an acoustic channel 4611 and an acoustic cavity structure. The acoustic channel 4611 extends through the baffle, the acoustic cavity structure may be disposed circumferentially of the acoustic channel, and the acoustic cavity structure communicates with the acoustic channel 4611. The acoustic cavity structure may include a first cavity 4612 and a second cavity 4613, where two ends of the first cavity 4612 are respectively in communication with the acoustic guide channel and the second cavity 4613, and the volume of the second cavity 4613 is greater than the volume of the first cavity 4612. The number of acoustic cavity structures may be one or more. When sound on the baffle side passes through the sound guide channel 4611, certain frequency components (e.g., sound components having frequencies equal to the resonant frequency of the acoustic cavity) may be absorbed by the acoustic cavity structure. This reduces interference cancellation of the sound of the frequency component at the listening position to some extent, thereby increasing the volume of the listening position. In some embodiments, the resonant frequency of the acoustic cavity may be varied by adjusting the size of the acoustic cavity structure, thereby changing the frequency band that the baffle can absorb. In some embodiments, a layer of breathable material (e.g., cotton, sponge) may also be provided in communication with the sound guide channel 4611 and the sound cavity structure to widen the resonant frequency range within the sound cavity structure, thereby enhancing the sound absorption effect of the sound cavity structure.

As shown in fig. (b), the acoustic structure 4620 may include an acoustic channel 4621 and an acoustic cavity structure 4622. The sound guide channel 4621 extends through the baffle, the sound cavity structure 4622 may surround the sound guide channel 4621, and the sound cavity structure 4622 communicates with the sound guide channel 4621. The acoustic cavity structure 4622 may be one or more. When sound on one side of the baffle passes through the acoustic structure 4620, the acoustic cavity structure 4622 performs a bandpass filtering function on the sound, i.e., the acoustic structure 4622 may pass sound in a specific frequency band while absorbing sound in other frequency bands. The passing sound will cancel other sounds at the listening position, and thus acoustic structure 4620 reduces the sound of that particular frequency band at the listening position. While for absorbed sounds, the acoustic structure 4620 enhances the sound of the other frequency bands at the listening position, since cancellation of the other sounds at the listening position is avoided.

As shown in fig. (c), the acoustic structure 4630 may include an acoustic channel 4631 and a passive diaphragm structure 4632, where the passive diaphragm structure 4632 is vertically disposed inside the acoustic channel 4631, and two ends of the passive diaphragm structure 4632 are fixedly connected with the inner wall of the baffle plate respectively. The number of passive diaphragm structures 4632 may be one or more. When sound on one side of the baffle passes through the acoustic structure 4630, the passive diaphragm structure 4632 can realize a filtering effect on the sound, so that strengthening of the sound with a specific frequency in the near-field listening and weakening of the sound with the specific frequency in the near-field listening are realized.

As shown in fig. (d), the acoustic structure 4640 may include an acoustic cavity structure 4641, and the acoustic cavity structure 4641 may be a hollow cavity in whole or in part within the baffle. In some embodiments, a plurality of through holes 4642 are formed in both sidewalls of the baffle. When sound on one side of the baffle enters the acoustic cavity structure 4641 through the through hole 4642, sound with a specific frequency can directly pass through the acoustic structure 4640, and sound with other frequencies (for example, sound with the same frequency as the resonance frequency of the acoustic structure 4640) is lost after entering the acoustic cavity structure 4641 due to the vibration of air inside the air. Sound of a specific frequency directly passing through the acoustic structure 4640 is reduced in volume because interference with sound emitted from other aperture portions is canceled at the listening position. It should be noted that the number and distribution of the through holes in the acoustic structure 4640 may be adjusted according to specific requirements, which will not be described in detail herein.

Thus, if it is desired to enhance the sound at a certain frequency at the listening position, the acoustic structure in the baffle may be arranged in one or more of the ways described above so that it absorbs the sound at that frequency, taking into account that the baffle blocks the sound emanating from only one of the hole portions. Thus, interference cancellation of sound of the frequency at the listening position, which is transmitted from the hole portions on both sides of the baffle plate, can be avoided. Conversely, if it is desired to reduce the sound at a certain frequency at the listening position, the acoustic structure in the baffle may be arranged to allow the sound at that frequency to pass directly.

In some embodiments, an acoustic structure may be provided in the baffle that alters the acoustic impedance of the baffle, which may be an acoustically resistive material that absorbs a portion of the sound passing through the baffle. The acoustically resistive material can include plastic, textile, metal, permeable material, woven material, screen material or mesh material, porous material, particulate material, polymeric material, or the like, or any combination thereof. The acoustic resistive material has an acoustic impedance that can range from 5MKS rayls to 500MKS rayls.

In some embodiments, similar to the acoustic structure provided in the baffle for changing the acoustic impedance of the baffle, a filtering structure may also be provided in the acoustic transmission structure of the open earphone, which may include a sound absorbing structure for absorbing sound in the target frequency range, thereby adjusting the sound effect of the open earphone in the spatial point (e.g., reducing high frequency leakage of the open earphone in the far field). The sound absorbing structure may include a resistive sound absorbing structure or a sound absorbing structure. The resistive sound absorbing structure may comprise a porous sound absorbing material or an acoustic gauze. The sound absorbing resistant structure may include, but is not limited to, perforated plates, microperforated plates, sheets, films, 1/4 wavelength resonance tubes, and the like, or any combination thereof. For more description of the filtering structure, see fig. 75-86 and their associated description, which are not repeated here.

Fig. 47 is a schematic view of a baffle structure of different shapes according to some embodiments of the present disclosure. As shown in fig. 47, in some embodiments, the baffles may be plate structures of uniform width or sequentially decreasing or increasing width from top to bottom. The baffle may be a symmetrical shaped structure. For example, the baffles may be V-shaped, wedge-shaped, isosceles triangle-shaped, trapezoid-shaped, semi-circular, or the like, or any combination thereof. The baffle may also be an asymmetrically shaped structure. For example, the baffles may be wavy, right-angled triangular, L-shaped, or the like, or any combination thereof.

Fig. 48 is a schematic diagram of a cell phone having a hole portion and a baffle structure according to some embodiments of the present disclosure. As shown, a plurality of holes are formed in top 4820 of the phone 4800 (i.e., "perpendicular" to the top surface of the phone display). By way of example only, the aperture portion 4801 may constitute a set of dipole sound sources (or point sound source array) for outputting sound. Baffle 4840 is disposed between the aperture portions 4801. A speaker 4830 is provided inside the housing of the mobile phone 4800. Sound generated by the speaker 4830 can be transmitted outward through the hole portion 4801.

In some embodiments, the aperture 4801 can emit a set of sounds of opposite (or approximately opposite) phase, identical (or approximately identical) amplitude. When a user places the aperture 4801 adjacent to his ear to hear voice information, the baffle 4840 "blocks" between one of the apertures and the user's ear, as described in the embodiments of FIGS. 31-47, corresponding to an increased path of sound propagation from the aperture to the ear, so that the aperture 4801 may emit a stronger near-field sound to the user. At the same time, the baffle 4840 has little effect on the sound radiated in the far field from the aperture portion, so that the aperture portion 4801 can reduce leakage to the surrounding environment due to interference cancellation of the sound.

In some embodiments, the number of the hole portions of the open earphone may be plural, and when the number of the hole portions of the open earphone exceeds two, that is, when there are two or more point sound sources in the open earphone, a baffle may be provided between each of the plurality of point sound sources. Through the cooperation of a plurality of point sound sources and a plurality of baffles, the open earphone can reach better output effect. In some embodiments, at least one set of point sources of opposite phase may be included between the plurality of point sources. For further explanation of the cooperation of the plurality of point sources and the plurality of baffles in the open earphone, a detailed description will be provided below in connection with fig. 49.

Fig. 49 is a schematic diagram of a distribution of point sound sources and baffles according to some embodiments of the present disclosure. As shown in fig. (a) and (b), the open earphone has 4 point sound sources (corresponding to 4 hole portions on the open earphone, respectively). Point sound source A ₁ And point sound source A ₂ Phase is the same, point sound source A ₃ And point sound source A ₄ Phase is the same, point sound source A ₁ And point sound source A ₃ The phases are opposite. Point sound source A ₁ Point sound source A ₂ Point sound source A ₃ Sum point sound source A ₄ The two baffles or a plurality of baffles which are spliced by two baffles which are arranged in a crossing way can be used for separation. Point sound source A ₁ And point sound source A ₃ (or Point Sound Source A) ₄ ) Point sound source A ₂ And point sound source A ₃ (or Point Sound Source A) ₄ ) The dipole sound sources as described elsewhere in this specification may be formed separately. As shown in the figure (a), the point sound source A ₁ Sum point sound source A ₃ Opposite arrangement, sum point sound source A ₂ Point sound source A ₄ Are adjacently arranged. As shown in the figure (b), the point sound source A ₁ Sum point sound source A ₂ Opposite arrangement, sum point sound source A ₃ Point sound source A ₄ Are adjacently arranged. As shown in fig. (c), the open earphone has 3 point sound sources (corresponding to 3 hole portions on the open earphone, respectively). Point sound source A ₁ Sum point sound source A ₂ Point sound source A ₃ The phases are reversed and two sets of dipole sound sources as described elsewhere in this specification may be formed. Point sound source A ₁ Point sound source A ₂ Sum point sound source A ₃ The separation may be by two intersecting baffles. As shown in fig. d, the open earphone has 3 point sound sources (corresponding to 3 hole portions on the open earphone, respectively). Point sound source A ₁ Sum point sound source A ₂ Phase is the same as that of point sound source A ₃ The phases are opposite. Wherein the point sound source A ₁ Sum point sound source A ₃ Point sound source A ₂ Sum point sound source A ₃ The dipole sound sources as described elsewhere in this specification may be formed separately. Point sound source A ₁ Point sound source A ₂ Sum point sound source A ₃ The separation may be by a V-shaped baffle.

Fig. 50 is a frequency response characteristic of near and far fields according to the arrangement and non-arrangement of baffles between the multi-point sound sources shown in fig. 49. As shown in fig. 50, in the near field, a multipoint sound source (e.g., point sound source a ₁ Point sound source A ₂ Point sound source A ₃ Sum point sound source A ₄ ) The volume of the sound when the baffle is arranged between the two sound sources is obviously larger than that of the sound when the baffle is not arranged between the multipoint sound sources, so that the volume of the sound when the baffle is arranged between the multipoint sound sources can be increased. In the far field, the leakage volume when the baffle is arranged between the multipoint sound sources is not much different from the leakage volume when the baffle is not arranged between the multipoint sound sources. Fig. 51 is a graph of a sound leakage index according to the case where baffles are provided and not provided between the plurality of point sound sources shown in fig. 49. As shown in fig. 51, the leakage index when baffles are provided between the multipoint sound sources is significantly reduced relative to the leakage index when no baffles are provided between the multipoint sound sources, and it can be explained that the leakage reduction capability when baffles are provided between the multipoint sound sources is significantly enhanced. Fig. 52 is a diagram of a leakage index corresponding to the two multipoint sound source distribution modes shown in fig. 49 (a) and (b). As shown in fig. 52, in a specific frequency rangeIn the four point sound sources, two point sound sources with the same phase are arranged opposite to each other on the baffle circumference side (for example, point sound source a in fig. 49 (b) ₁ Sum point sound source A ₂ Point sound source A ₃ Sum point sound source A ₄ ) The leakage index (shown as "(b)" in fig. 52) is significantly smaller than that of two point sound sources (e.g., point sound source a in fig. 49 (a)) with opposite phases disposed opposite to each other on the baffle peripheral side ₁ Sum point sound source A ₃ Point sound source A ₂ Sum point sound source A ₄ ) The leakage index (shown in fig. 52 "(a)") at the time may indicate that the leakage-reducing ability of two point sound sources having the same phase relative to each other or point sound sources having opposite phases disposed adjacently to each other on the peripheral side of the baffle plate is stronger.

According to the above, in some embodiments, when the open earphone has a plurality of hole portions, in order to keep the open earphone outputting as loud sound as possible in the near field while suppressing leakage sound in the far field, a baffle may be provided between each of the plurality of hole portions, i.e., each hole portion is partitioned by the baffle. Preferably, the plurality of hole portions output sounds having the same (or approximately the same) phase or opposite (or approximately opposite) phases, respectively. More preferably, the hole portions outputting the sounds in the same phase may be disposed opposite to each other, and the hole portions outputting the sounds in opposite phases may be disposed adjacently to each other.

In some embodiments, to further enhance the sound output effect of the open earphone, the open earphone may include two speakers. The two speakers are controlled by the same or different controllers, respectively, and can produce sounds having certain phase and amplitude conditions satisfied. In some embodiments, the open earphone may include a first speaker and a second speaker. The controller may control the first speaker and the second speaker to generate sounds having a certain phase and amplitude condition (e.g., sounds having the same amplitude but having a phase difference (e.g., opposite phases), sounds having different amplitudes and having a phase difference (e.g., opposite phases), etc.) through one control signal. The first speaker outputs sound through the two first hole portions, and the second speaker outputs sound through the two second hole portions.

For human ear hearing, the frequency band of the hearing sound is mainly focused on the middle-low frequency band, and the frequency band is mainly aimed at optimizing the volume of the hearing sound. If the listening position is fixed, the listening volume is obviously increased and the leakage volume is basically unchanged by adjusting the parameters of the two groups of hole parts by a certain means (the increment of the listening volume is larger than that of the leakage volume). In the high frequency band, the sound leakage reducing effect of the two groups of hole parts is weakened, and in the frequency band, the sound leakage reducing effect is mainly used as an optimization target. By adjusting the parameters of the two groups of holes with different frequencies by a certain means, the further reduction of the leakage sound and the expansion of the leakage sound band can be realized.

Fig. 53 is an exemplary structural diagram of another open earphone according to some embodiments of the present description. In some embodiments, the open earphone 5300 may include a housing 5310, a first speaker 5320, a second speaker 5330, and a controller. The first speaker 5320 outputs sounds from two first hole portions. The second speaker 5330 outputs sounds from two second hole portions. Regarding the first speaker 5320 and the first aperture, the second speaker 5330 and the second aperture, and the structure therebetween, reference may be made to the foregoing detailed description regarding one speaker and two apertures. In some embodiments, a cartridge and a motherboard 5322 may be disposed within the housing 5310, the cartridge may form at least part of the structure of a speaker capable of producing sound with the cartridge, the sound being transmitted to and output from the corresponding aperture along the corresponding acoustic path, respectively. In some embodiments, the open earphone 5300 may include two cartridges, a first cartridge 5321 and a second cartridge 5331, respectively. The first movement 5321 constitutes at least part of the structure of the first speaker 5320. The second movement 5331 constitutes at least part of the structure of the second speaker 5330. The first speaker 5320 generates sound with the first movement 5321 corresponding thereto, the sound being transmitted to and output from the first hole portion along the corresponding acoustic path. The second speaker 5330 generates sound with the second movement 5331 corresponding thereto, the sound being transmitted to and output from the second hole portion along the corresponding acoustic path. In some embodiments, the number of main boards 5322 may be one, with the main boards 5322 electrically connected to two cartridges (e.g., first cartridge 5321 and second cartridge 5331) to control the sound production of the two cartridges. In some embodiments, the number of main boards 5322 may be two, and the two main boards are respectively electrically connected to the two cores, so as to realize separate control of sound production of the two cores. In some embodiments, the open earphone 5300 may also include a power supply 5340. The power supply 5340 may provide power to various components (e.g., speakers, cartridges, etc.) of the open headset 5300. A power supply 5340 may be electrically connected to first speaker 5320 and/or second speaker 5330 and/or the cartridge to provide electrical power thereto. In some embodiments, the first speaker 5320 and the second speaker 5330 may each output sound of a different frequency. The controller is configured to cause the first speaker 5320 to output sound in a first frequency range from the two first aperture portions and to cause the second speaker 5330 to output sound in a second frequency range from the two second aperture portions, wherein the second frequency range includes frequencies higher than the first frequency range. For example, the first frequency may range from 100Hz to 1000Hz and the second frequency may range from 1000Hz to 10000 Hz.

In some embodiments, the first speaker 5320 may be a low frequency speaker and the second speaker 5330 a medium and high frequency speaker. Because the frequency response characteristics of the low-frequency loudspeaker and the medium-high-frequency loudspeaker are different, the output sound frequency bands are also different, and the frequency division of the sound in the high-low frequency band can be realized by using the low-frequency loudspeaker and the medium-high-frequency loudspeaker, so that the output of near-field sound and far-field leakage reduction can be carried out by respectively constructing a low-frequency dipole sound source and a medium-high-frequency dipole sound source. For example, the first speaker 5320 may provide a dipole sound source outputting low frequency sounds through two first hole portions, mainly for outputting sounds of a low frequency band. Two first hole portions may be distributed on both sides of the auricle for increasing the sound volume near the near-field ear. The second speaker 5330 can provide a dipole sound source outputting a middle-high frequency band through the two second hole portions, and can reduce leakage sound of the middle-high frequency band by controlling the interval of the two second hole portions. The two second hole portions may be distributed on both sides of the auricle, or may be distributed on the same side of the auricle. When the user wears the open earphone 5300, the housing 5310 may have the two second hole portions closer to the user's ears than the two first hole portions.

Fig. 54 is a graph of leakage of dipole and single point sources as shown according to some embodiments of the present description as a function of frequency. Under certain conditions, the far-field leakage sound generated by the dipole sound source increases with the frequency, namely, the leakage-sound reducing capability of the dipole sound source in the far field decreases with the frequency, relative to the far-field leakage sound volume of the single-point sound source. For a clearer description, a curve of far-field leakage sound with frequency will be described with reference to fig. 54.

The dipole sound sources corresponding to fig. 54 are fixed in pitch, and the two point sound sources are identical in amplitude and opposite in phase. Wherein the dashed line represents the change curve of the single-point sound source leakage volume at different frequencies, and the solid line represents the change curve of the dipole sound source leakage volume at different frequencies. The abscissa represents the frequency (f) of sound in hertz (Hz), and the ordinate uses the normalized parameter α as an index for evaluating the leakage volume.

As shown in fig. 54, when the frequency is 6000Hz or less, the far-field leakage sound generated by the dipole sound source is smaller than the far-field leakage sound generated by the single-point sound source, and increases with the increase of the frequency; when the frequency is close to 10000Hz (e.g., above about 8000 Hz), the far-field leakage sound generated by the dipole sound source is greater than the far-field leakage sound generated by the single point sound source. In some embodiments, the frequency at the intersection of the dipole sound source and the single point sound source with the frequency variation curve may be used as the upper limit frequency of the leakage sound of the dipole sound source according to the above.

For illustrative purposes only, when the frequency is small (e.g., in the range of 100Hz-1000 Hz), the leakage reduction capability of the dipole sound source (i.e., small alpha value) is strong (-80 dB or less), so that it is possible to target an increase in the volume of the listening sound in this frequency band; when the frequency is large (for example, in the range of 1000Hz-8000 Hz), the leakage-reducing ability of the dipole sound source is weak (-80 dB or more), so that the leakage reduction can be targeted for optimization in this frequency band.

In connection with fig. 54, the frequency division point of the frequency can be determined according to the variation trend of the leakage-reducing capability of the dipole sound source, and the parameter of the dipole sound source is adjusted according to the frequency division point, so as to improve the leakage-reducing effect of the open earphone. For example, frequencies at which the α value corresponds at a particular value (e.g., -60dB, -70dB, -80dB, -90dB, etc.) may be considered as crossover points. The parameters of the dipole sound source are determined by setting frequency segments below the crossover point to improve near-field listening as a main target and frequency segments above the crossover point to reduce far-field leakage as a main target. In some embodiments, a high frequency band where the sound frequency is high (e.g., sound output by a tweeter) and a low frequency band where the sound frequency is low (e.g., sound output by a woofer) may be determined based on crossover points. For more details about the crossover point, see elsewhere in this specification (e.g., fig. 57 and its associated description).

As is clear from fig. 54, the dipole sound source has a weak sound-leakage-reducing capability in the high frequency band (the higher frequency band determined by the crossover point) and has a strong sound-leakage-reducing capability in the low frequency band (the lower frequency band determined by the crossover point). And under certain sound frequency, the intervals of the dipole sound sources are different, the generated sound-reducing and leaking capacities are different, and the difference between the volume of the sound and the volume of the leaking sound is also different. For a clearer description, a curve of far-field leakage sound as a function of dipole sound source spacing will be described with reference to fig. 55A and 55B.

Fig. 55A and 55B are exemplary graphs showing near-field listening volume and far-field leakage volume as a function of dipole sound source spacing according to some embodiments of the present description. Fig. 55B is a graph obtained by normalizing fig. 55A.

In FIG. 55A, a solid line shows a plot of the volume of listening of a dipole sound source as a function of the spacing of the dipole sound sources, a broken line shows a plot of the volume of leakage of a dipole sound source as a function of the spacing of the dipole sound sources, and an abscissa shows the spacing d between two point sound sources of the dipole sound source and a reference spacing d ₀ Is a pitch ratio d/d of ₀ The ordinate indicates the volume of sound (in dB). Pitch ratio d/d ₀ The change of the distance between the two point sound sources of the dipole sound source can be reflected. In some embodiments, the reference spacing d ₀ Can be selected within a specific range. For example, d ₀ May be a specific value taken in the range of 2.5mm to 10 mm. In some embodiments, the reference spacing d ₀ Can be based on listening positionAnd (5) determining. By way of example only, take d in FIG. 55A ₀ Equal to 5mm as a reference value for the dipole sound source spacing variation.

Under the condition of a certain sound frequency, as the interval between the dipole sound sources is increased, the listening volume and the leakage volume of the dipole sound sources are increased. When the dipole sound source spacing d is equal to the reference spacing d ₀ Ratio d/d of (2) ₀ When the ratio is smaller than the threshold value, the increment of the volume of the sound of the dipole is larger than that of the volume of the leakage along with the increment of the interval of the sound sources of the dipole, namely the increment of the volume of the sound is more obvious than that of the volume of the leakage. For example, as shown in FIG. 55A, the dipole sound source spacing d is from the reference spacing d ₀ Ratio d/d of (2) ₀ When the difference is 2, the difference between the volume of the listening sound and the volume of the leaking sound is about 20dB; ratio d/d ₀ At 4, the difference between the volume of the listening and the volume of the leakage is about 25dB. In some embodiments, when the dipole sound source spacing d is from the reference spacing d ₀ Ratio d/d of (2) ₀ When the ratio threshold is reached, the ratio of the volume of the dipole sound source to the volume of the leakage sound reaches a maximum value. At this time, as the dipole sound source interval further increases, the curve of the listening volume and the curve of the leakage volume gradually tend to be parallel, i.e., the increase in the listening volume and the increase in the leakage volume remain the same. For example, as shown in FIG. 55B, the dipole sound source spacing ratio d/d ₀ When the difference between the volume of the sound of the dipole sound source and the volume of the leakage sound is 5, or 6 or 7, the difference is kept consistent, and the difference is about 25dB, namely the increment of the volume of the sound is the same as the increment of the volume of the leakage sound. In some embodiments, the spacing ratio d/d of the dipole sound source spacing ₀ The ratio threshold of (2) may be in the range of 0-7.

In some embodiments, the ratio threshold may be determined based on the difference change in the dipole sound source listening volume and the leakage volume of fig. 55A. For example, the ratio corresponding to the maximum difference between the listening volume and the leakage volume may be determined as the ratio threshold. As shown in FIG. 55B, when the pitch ratio d/d ₀ When the ratio is smaller than the ratio threshold (e.g. 4), the normalized listening curve is in an ascending trend (curve slope is larger than 0) along with the increase of the dipole sound source distance, namely the listening volume increment is larger than the leakage volume increment; when the spacing ratio d/d ₀ Greater than a ratio ofAt the threshold value, the slope of the normalized listening curve gradually approaches 0 as the dipole sound source spacing increases, and is parallel to the normalized leakage curve, i.e., the listening volume increment is no longer greater than the leakage volume increment as the dipole sound source spacing increases.

From the above, it can be seen that if the listening position is fixed, the near-field listening volume is significantly increased and the far-field leakage volume is only slightly increased by adjusting the parameters of the dipole sound source by a certain means (i.e., the near-field listening volume is increased more than the far-field leakage volume). For example, two sets of dipole sound sources (such as a set of high-frequency dipole sound sources and a set of low-frequency dipole sound sources) are provided, and the spacing of each set of dipole sound sources is adjusted by a certain means so that the spacing between the high-frequency dipole sound sources is smaller than the spacing between the low-frequency dipole sound sources. Because the low-frequency-band dipole sound source has smaller leakage sound (stronger leakage sound reducing capability), the high-frequency-band dipole sound source has larger leakage sound (weaker leakage sound reducing capability), and the high-frequency-band dipole sound source is smaller in interval, the volume of the listening sound can be obviously larger than that of the leakage sound, so that the leakage sound is reduced.

In some embodiments, when the open earphone includes two speakers, there is a certain distance between two holes corresponding to each speaker, and the distance affects the near-field listening volume transmitted to the ear of the wearer by the open earphone and the far-field leaking volume propagated to the environment. In some embodiments, when the spacing between the holes corresponding to the tweeters is smaller than the spacing between the holes corresponding to the woofers, the volume of sound that can be heard by the user's ears may be increased, and less leakage sound may be generated, avoiding sound being heard by others in the vicinity of the open-ended earphone user. According to the above description, the open earphone can be effectively used as an open earphone even in a relatively quiet environment.

Fig. 56 is an exemplary block diagram of an open earphone according to some embodiments of the present description. As shown in fig. 56, the open earphone 5600 may include an electronic crossover module 5610, first and second speakers 5640 and 5650, an acoustic path 5645, an acoustic path 5655, two first holes 5647, and two second holes 5657. In some embodiments, the open earphone 5600 further includes a controller (not shown) as part of which the electronic crossover module 5610 is used to generate electrical signals for input to the different speakers. The connections between the different components in the open earphone 5600 may be wired or wireless.

The electronic frequency division module 5610 may perform frequency division processing on the sound source signal. The audio source signals may be from one or more audio source devices (e.g., a memory storing audio data) integrated within the open earphone 5600, or may be audio signals received by the open earphone 5600 via wired or wireless means. In some embodiments, the electronic divide module 5610 may decompose the input audio source signal into two or more divided signals containing different frequency components. For example, the electronic crossover module 5610 may decompose the audio source signal into a first crossover signal (or crossover signal 1) with high frequency sound components and a second crossover signal (or crossover signal 2) with low frequency sound components. For convenience, the divided signal with the high frequency sound component may be directly referred to as a high frequency signal, and the divided signal with the low frequency sound component may be directly referred to as a low frequency signal.

The low frequency signal refers to a sound signal having a frequency in a first lower frequency range, and the high frequency signal refers to a sound signal having a frequency in a second higher frequency range. The first and second frequency ranges may or may not include overlapping frequency ranges, and the second frequency range includes frequencies higher than the first frequency range. For example only, the first frequency range may refer to frequencies below a first frequency threshold and the second frequency range may refer to frequencies above a second frequency threshold. The first frequency threshold may be lower, equal to, or higher than a second frequency threshold. For example, the first frequency threshold may be less than the second frequency threshold (e.g., the first frequency threshold may be 600Hz and the second frequency threshold 700 Hz), which indicates that there is no overlap between the first frequency range and the second frequency range. As another example, the first frequency threshold may be equal to the second frequency threshold (e.g., both the first frequency threshold and the second frequency threshold are 650Hz or any other frequency value). As another example, the first frequency threshold may be greater than the second frequency threshold, which indicates that there is overlap between the first frequency range and the second frequency range. In this case, the difference between the first frequency threshold and the second frequency threshold may not exceed the third frequency threshold. The third frequency threshold may be a fixed value, for example, 20hz,50hz,5600hz,150hz,200hz, or a value related to the first frequency threshold and/or the second frequency threshold (for example, 5%,10%,15% of the first frequency threshold, etc.), or a value flexibly set by the user according to the actual scenario, which is not limited herein. It should be noted that the first frequency threshold and the second frequency threshold may be flexibly set according to different situations, which is not limited herein.

In some embodiments, electronic frequency division module 5610 may include frequency divider 5615, signal processors 5620 and 5630. Divider 5615 may be used to divide the audio source signal into two or more divided signals containing different frequency components, e.g., divided signal 1 with a high frequency sound component and divided signal 2 with a low frequency sound component. In some embodiments, divider 5615 may be any electronic device that may perform a signal splitting function including, but not limited to, one or any combination of passive filters, active filters, analog filters, digital filters, and the like.

The signal processors 5620 and 5630 may each further process the divided signal to meet the requirements of subsequent sound output. In some embodiments, the signal processor 5620 or 5630 may include one or more signal processing components. For example, the signal processor may include, but is not limited to, one or any combination of an amplifier, an amplitude modulator, a phase modulator, a delay, a dynamic gain controller, and the like.

After the signal processors 5620 or 5630 perform signal processing on the divided signals, respectively, the divided signals may be transmitted to the first speaker 5640 and the second speaker 5650, respectively. In some embodiments, the sound signal that is incoming to the first speaker 5640 may be a sound signal that includes a lower frequency range (e.g., a first frequency range), and thus the first speaker 5640 may also be referred to as a low frequency speaker. The sound signal that is transmitted into the second speaker 5650 may be a sound signal that includes a higher frequency range (e.g., a second frequency range), and thus the second speaker 5650 may also be referred to as a tweeter. The first speaker 5640 and the second speaker 5650 may convert respective sound signals into low-frequency sound and high-frequency sound, respectively, and propagate to the outside.

In some embodiments, two acoustic paths 5645 (also called first acoustic paths) may be formed between the first speaker 5640 and the two first hole portions 5647, and the first speaker 5640 is acoustically coupled to the two first hole portions 5647 through the two acoustic paths 5645, respectively, and propagates sound out from the two first hole portions 5647. Two acoustic paths 5655 (also called second acoustic paths) may be formed between the second speaker 5650 and the two second hole portions 5657, and the second speaker 5650 is acoustically coupled to the two second hole portions 5657 through the two acoustic paths 5655, respectively, and propagates sound out from the two second hole portions 5657. In some embodiments, to reduce far-field leakage of the open earphone 5600, the first speaker 5640 may be caused to generate low-frequency sounds of equal (or approximately equal), opposite (or approximately opposite) magnitudes at the two first aperture portions 5647, respectively, and the second speaker 5650 may be caused to generate high-frequency sounds of equal (or approximately equal), opposite (or approximately opposite) magnitudes at the two second aperture portions 5657, respectively. Thus, based on the principle of cancellation of acoustic wave interference, far-field leakage of low-frequency sound (or high-frequency sound) is reduced. According to the above description of fig. 54, fig. 55A and 55B, further considering that the wavelength of the low-frequency sound is larger than that of the high-frequency sound, and in order to reduce interference cancellation of the sound in the near field (e.g., listening position of the user's ear), the distance between the first hole portions and the distance between the second hole portions may be set to different values, respectively. For example, assuming that two first hole portions have a first pitch therebetween and two second hole portions have a second pitch therebetween, the first pitch may be made larger than the second pitch. In some embodiments, the first pitch and the second pitch may be any value. For example only, the first pitch may be no greater than 40mm and the second pitch may be no greater than 7mm. For more description of the first pitch and the second pitch, see description elsewhere in this specification (e.g., related description in fig. 57).

As shown in fig. 56, the first speaker 5640 may include a transducer 5643. The transducer 5643 transmits sound through the acoustic path 5645 to the first aperture 5647. The second speaker 5650 may include a transducer 5653. The transducer 5653 transmits sound through the acoustic path 5655 to the second aperture 5657. In some embodiments, the transducer may include, but is not limited to, one of a transducer of an air conduction speaker, a transducer of a bone conduction speaker, an underwater acoustic transducer, an ultrasonic transducer, or the like, or any combination thereof. In some embodiments, the working principle of the transducer may include, but is not limited to, one of moving coil type, moving iron type, piezoelectric type, electrostatic type, magnetostrictive type, etc., or any combination thereof.

In some alternative embodiments, the open earphone 5600 utilizes a transducer to achieve signal crossover, and the first speaker 5640 and the second speaker 5650 can convert the input audio source signal into a low frequency signal and a high frequency signal, respectively. Specifically, the first speaker 5640 may convert the sound source signal into low-frequency sound with a low-frequency component through the transducer 5643; the low frequency sound may be transmitted to the two first hole portions 5647 along the two different acoustic paths 5645, and propagated to the outside through the first hole portions 5647. The second speaker 5650 may convert the sound source signal into a high-frequency sound with a high-frequency component through the transducer 5653; the high-frequency sound may be transmitted to the two second hole portions 5657 along the two different acoustic paths 5655, and propagated to the outside through the second hole portions 5657.

In some alternative embodiments, the acoustic path connecting the transducer and aperture (e.g., acoustic paths 5645 and 5655) may affect the nature of the transmitted sound. For example, the acoustic path may attenuate the transmitted sound to some degree or alter the phase of the transmitted sound. In some embodiments, the acoustic path may be formed by a structure of one or any combination of a sound guide tube, a sound cavity, a resonant cavity, a sound hole, a sound slit, a tuning net, and the like. In some embodiments, an acoustic path may also include an acoustic resistive material therein, the acoustic resistive material having a particular acoustic impedance. For example, the acoustic impedance may range from 5MKS rayls to 500MKS rayls. The acoustically resistive material can include, but is not limited to, one or any combination of plastic, textile, metal, permeable material, woven material, screen material, mesh material, and the like. By providing acoustic paths with different acoustic impedances, the sound output by the transducer can be acoustically filtered such that the sound output by the different acoustic paths has different frequency components.

In some alternative embodiments, the open earphone 5600 utilizes an acoustic path to achieve signal division. Specifically, the sound source signal is input to a specific speaker and converted into sound containing high and low frequency components, and the sound signal propagates along acoustic paths having different frequency selection characteristics. For example, the sound signal may be transmitted along an acoustic path having a low-pass characteristic to the corresponding hole portion to generate an outwardly propagating low-frequency sound, during which the high-frequency sound is absorbed or attenuated by the acoustic path having the low-pass characteristic. As such, the sound signal may be transmitted along the acoustic path having the high-pass characteristic to the corresponding hole portion to generate the outwardly propagating high-frequency sound, and in this process, the low-frequency sound is absorbed or attenuated by the acoustic path having the high-pass characteristic.

In some embodiments, the controller in the open earphone 5600 may cause the first speaker 5640 to output sound in a first frequency range (i.e., low frequency sound) and the second speaker 5650 to output sound in a second frequency range (i.e., high frequency sound). In some embodiments, the open earphone 5600 may further comprise a housing. The housing is configured to carry the first speaker 5640 and the second speaker 5650 and has two first and second apertures 5647, 5657 in acoustic communication with the first and second speakers 5640, 5650, respectively. The housing is secured to the user's head and positions the two speakers adjacent the user's ears and not occluding the user's ear canal. In some embodiments, the housing may have the second aperture 5657 acoustically coupled to the second speaker 5650 closer to the desired location of the user's ear (e.g., the entrance to the ear canal), while the first aperture 5647 acoustically coupled to the first speaker 5640 is farther from the desired location. In some embodiments, the housing encloses the speaker and defines, through the cartridge, a front chamber and a rear chamber forming a corresponding speaker, the front chamber being acoustically couplable to one of the two apertures and the rear chamber being acoustically couplable to the other of the two apertures. For example, the front chamber of the first speaker 5640 may be acoustically coupled to one of the two first aperture portions 5647 and the rear chamber of the first speaker 5640 may be acoustically coupled to the other of the two first aperture portions 5647; the front chamber of the second speaker 5650 may be acoustically coupled to one of the two second aperture portions 5657 and the rear chamber of the second speaker 5650 may be acoustically coupled to the other of the two second aperture portions 5657. In some embodiments, apertures (e.g., first aperture 5647, second aperture 5657) may be provided on the housing.

Fig. 57 is an exemplary flow chart of an acoustic output method according to some embodiments of the present description. In some embodiments, the process 5700 can be implemented by the open earphone 5300 (and/or the open earphone 5600).

In 5710, the open earphone 5300 may acquire a sound source signal output by the audio device.

In some embodiments, the open headset 5300 can connect to the audio device by wire (e.g., via a data line connection) or wirelessly (e.g., via a bluetooth connection) and receive a radio signal. The audio device may include a mobile device, such as a computer, a cell phone, a wearable device, or other carrier that may process or store audio source data.

In 5720, the open earphone 5300 may divide the audio source signal.

The sound source signal can be decomposed into two or more sound signals containing different frequency components after the frequency division processing. For example, the sound source signal may be decomposed into a low frequency signal with a low frequency component and a high frequency signal with a high frequency component. In some embodiments, the low frequency signal refers to a sound signal having a frequency in a first, lower frequency range, and the high frequency signal refers to a sound signal having a frequency in a second, higher frequency range. In some embodiments, the first frequency range includes frequencies below 650Hz and the second frequency range includes frequencies above 53000 Hz.

In some embodiments, the open earphone 5300 may divide the audio source signal by an electronic frequency division module (e.g., electronic frequency division module 5610). For example, the audio source signal may be decomposed into one or more sets of high frequency signals and one or more sets of low frequency signals by an electronic frequency division module.

In some embodiments, the open earphone 5300 may divide the audio source signal based on one or more division points. The division point refers to a signal frequency that distinguishes a first frequency range from a second frequency range. For example, when there is an overlapping frequency between the first frequency range and the second frequency range, the division point may be a characteristic point within the overlapping frequency range (e.g., a low frequency boundary point, a high frequency boundary point, a center frequency point, etc. of the overlapping frequency range). In some embodiments, the crossover point may be determined from the relationship between the frequency and the leakage of the open earphone (e.g., the curves shown in fig. 54, 55A, and 55B), or the user may directly designate a particular frequency as the crossover point.

In step 5730, the open earphone 5300 may perform signal processing on the sound signal after the frequency division.

In some embodiments, the open earphone 5300 may further process the split signals (e.g., high frequency signals and low frequency signals) to meet the requirements of subsequent sound output. For example, the open earphone 5300 may further process the split signal by a signal processor (e.g., signal processor 5620, signal processor 5630, etc.). The signal processor may include one or more signal processing components. For example only, the processing of the divided signal by the signal processor may include adjusting the amplitude of the corresponding portion of the frequencies in the divided signal. Specifically, in the case where there is an overlap between the first frequency range and the second frequency range, the signal processor may respectively adjust the intensities (magnitudes) of the corresponding sound signals in the overlapping frequency ranges, so as to avoid the result of excessive sound in the overlapping frequency ranges due to the superposition of multiple sound signals in the subsequently outputted sound.

At 5740, the open earphone 5300 may convert the processed sound signal into sound having different frequency components and output the sound.

In some embodiments, the open earphone 5300 may output sound through the first speaker 5640 and/or the second speaker 5650. In some embodiments, the first speaker 5640 may output low frequency sound containing only low frequency components, and the second speaker 5650 may output high frequency sound containing only high frequency components.

In some embodiments, the first speaker 5640 may output low frequency sound from two first hole portions 5647 and the second speaker 5650 may output high frequency sound from two second hole portions 5657. In some embodiments, the acoustic path between the same speaker and its corresponding different aperture may be designed in different situations. For example, the acoustic path between the same speaker and its corresponding different aperture may be configured to have approximately the same equivalent acoustic impedance by providing the shape and/or size of the first aperture (or the second aperture), or providing a lumen structure or an acoustic resistive material with some damping in the acoustic path. In this case, when two sets of sounds of the same amplitude and opposite phases are output from the same speaker, the two sets of sounds still have the same amplitude and opposite phases when they reach the corresponding hole portions through different acoustic paths, respectively.

In connection with the structure of the open earphone described in fig. 56, the first speaker 5640 may output two sets of low-frequency sound signals in opposite phases through the two first hole portions 5647, and the second speaker 5650 may output two sets of high-frequency sound signals in opposite phases through the two second hole portions 5657. Based on this, the first speaker 5640 and the second speaker 5650 constitute a low-frequency dipole sound source and a high-frequency dipole sound source, respectively. Thus, the far-field leakage of the low-frequency dipole sound source (or the high-frequency dipole sound source) is reduced based on the principle of the interference cancellation of the sound waves.

Further considering that the wavelength of the low-frequency sound is larger than that of the high-frequency sound, the distance between the first hole portions 5647 and the distance between the second hole portions 5657 may be set to different values, respectively, in order to reduce interference cancellation of the sound in the near field (for example, listening position of the user's ear) while ensuring that the far-field leakage sound is small. In some embodiments, when the first distance between the two first hole portions 5647 corresponding to the first speaker 5640 is increased, the near-field listening increment of the open earphone is larger than the far-field leakage increment, so that a higher near-field sound volume and a lower far-field leakage in a low frequency range can be achieved. Further, the second pitch between the two second hole portions 5657 corresponding to the second speaker 5650 is reduced, and although the near-field sound volume in the high frequency range may be affected to some extent, the far-field sound leakage in the high frequency range may be significantly reduced. Therefore, by reasonably designing the interval between the two second hole parts and the interval between the two first hole parts, the open earphone can have stronger sound leakage reducing capability.

For purposes of illustration, there is a first spacing between two first hole portions and a second spacing between two second hole portions, and the first spacing is greater than the second spacing. In some embodiments, the first pitch and the second pitch may be any value. For example only, the first pitch may be no less than 8mm, the second pitch may be no greater than 12mm, and the first pitch is greater than the second pitch. In some embodiments, the first spacing may be at least more than 2 times the second spacing in order to further increase the leakage reduction capability of the open earphone.

In some embodiments, the amplitude and phase parameters of the sound output by the two groups of hole parts can be adjusted to improve the far-field sound leakage reduction capability of the open earphone. For the regulation of the amplitude and phase of the output sound of the two sets of hole portions, see, in particular, fig. 63A to 69B and their associated description.

It should be noted that the above description of the process 5700 is only for illustration and description, and does not limit the application scope of the present disclosure. Various modifications and changes to the procedure 5700 will be apparent to those skilled in the art in light of the present description. However, such modifications and variations are still within the scope of the present description. For example, the processing of the divided signal in step 5730 may be omitted, and the divided signal may be directly output to the external environment through the hole portion.

Fig. 58 is a schematic diagram of an open earphone according to some embodiments of the present description.

Fig. 58 shows a simplified representation of a speaker in an open earphone. In fig. 58, each speaker has a front side and a rear side, and there is a structure of a corresponding front chamber (i.e., a first acoustic path) and rear chamber (i.e., a second acoustic path) at the front side or the rear side of the speaker. In some embodiments, these structures may have the same or approximately the same equivalent acoustic impedance so that the speaker is symmetrically loaded. The symmetrical loading of the transducers may cause sound sources to be formed at different aperture portions that satisfy amplitude and phase relationships (e.g., equal amplitude, opposite phase), thereby forming a particular radiated sound field in the high and/or low frequency range (e.g., near field sound is enhanced while far field leakage is suppressed).

To more clearly describe the actual use of the open earphone 5800, the position of the user's ear E is shown in fig. 58 for illustration. Here, the left diagram (a) in fig. 58 mainly shows an application scene of the first speaker 5640. The first speaker 5640 is acoustically coupled to the two first hole portions 5647 through acoustic paths 5645. The right diagram (b) in fig. 58 mainly shows an application scene of the second speaker 5650. The second speaker 5650 is acoustically coupled to the two second hole portions 5657 through acoustic paths 5655.

The first speaker 5640 may vibrate under the drive of an electrical signal, and the vibration may produce a set of equal magnitude, opposite phase (180 degrees out of phase) sounds. In some embodiments, the first speaker 5640 may include a diaphragm that may vibrate when driven by an electrical signal, and the front and back surfaces of the diaphragm may output both positive and negative sounds. In fig. 58, sounds of different phases are exemplified by "+" and "-" where "+" represents a positive phase sound and "-" represents a negative phase sound.

In some embodiments, the speaker may be enclosed by a housing, inside which sound channels are provided, connected to the front and rear sides of the speaker, respectively, so as to form an acoustic path. For example, the front cavity of the first speaker 5640 is coupled to one of the two first aperture portions 5647 through a first acoustic path (i.e., the front half of the acoustic path 5645), and the rear cavity of the first speaker 5640 is acoustically coupled to the other of the two first aperture portions 5647 through a second acoustic path (i.e., the rear half of the acoustic path 5645). The normal-phase sound and the reverse-phase sound outputted from the first speaker 5640 are outputted from the two first hole portions 5647, respectively. For another example, the front cavity of the second speaker 5650 is coupled to one of the two second apertures 5657 through a third acoustic path (i.e., the front half of the acoustic path 5655), and the rear cavity of the second speaker 5650 is coupled to the other of the two second apertures 5657 through a fourth acoustic path (i.e., the rear half of the acoustic path 5655). The normal-phase sound and the reverse-phase sound output from the second speaker 5650 are output from the two second hole portions 5657, respectively.

In some embodiments, the acoustic path may affect the nature of the transmitted sound. For example, the acoustic path may attenuate the transmitted sound to some degree or alter the phase of the transmitted sound. In some embodiments, the acoustic path may be formed by a structure of one or any combination of a sound guide tube, a sound cavity, a resonant cavity, a sound hole, a sound slit, a tuning net, and the like. In some embodiments, an acoustic path may also include an acoustic resistive material therein, the acoustic resistive material having a particular acoustic impedance. For example, the acoustic impedance may range from 5MKS rayls to 500MKS rayls. In some embodiments, in order for the sound transmitted by the front and rear chambers of the speaker to not be disturbed (or for the change resulting from the disturbance to be the same), the corresponding front and rear chambers of the speaker may be arranged to have approximately the same equivalent acoustic impedance. For example, the same acoustic resistance material, holes having the same size or shape, and the like are used.

The spacing between the two first hole portions 5647 of the first speaker 5640 may be represented as d ₁ The spacing between the two second hole portions 5657 of the second speaker 5650 (i.e., the first spacing) may be represented as d ₂ (i.e., the second pitch). By setting the distance between the hole portions corresponding to the first speaker 5640 and the second speaker 5650, for example, such that the pitch between the two first hole portions 5647 is larger than the pitch between the two second hole portions 5657 (i.e., d ₁ ＞d ₂ ) The high-frequency audio amplifier can realize higher volume output in a low frequency band and has stronger audio leakage reducing capability in a high frequency band.

Fig. 59A and 59B are schematic diagrams of sound output according to some embodiments of the present description.

In some embodiments, the open earphone may generate sound in the same frequency range through two transducers and propagate out through different aperture portions. In some embodiments, different transducers may be controlled by the same or different controllers, respectively, and may produce sounds having certain phase and amplitude conditions (e.g., sounds of the same amplitude but opposite phases, sounds of different amplitudes and opposite phases, etc.). For example, the controller may cause electrical signals input to the two low frequency transducers of the speaker to have the same amplitude and opposite phases, such that when sound is formed, the two low frequency transducers may output low frequency sounds of the same amplitude but opposite phases.

Specifically, two transducers of speakers (e.g., the first speaker 5640, the second speaker 5650) may be disposed in parallel within an open earphone, one for outputting positive phase sound and the other for outputting negative phase sound. As shown in fig. 59A, the first speaker 5640 on the right side may include two transducers 5643, two acoustic paths 5645, and two first hole portions 5647, and the second speaker 5650 on the left side may include two transducers 5653, two acoustic paths 5655, and two second hole portions 5657. Driven by electrical signals of opposite phase, the two transducers 5643 may produce a set of low frequency sounds of opposite phase (180 degrees of phase opposition). One of the two transducers 5643 outputs positive sound (e.g., the transducer located below) and the other outputs negative sound (e.g., the transducer located above), and two sets of low frequency sounds of opposite phases are transmitted along two acoustic paths 5645 to the two first hole portions 5647, respectively, and propagate outward through the two first hole portions 5647. Similarly, driven by electrical signals of opposite phase, the two transducers 5653 may produce a set of high frequency sounds of opposite phase (180 degrees of opposite phase). One of the two transducers 5653 outputs normal-phase high-frequency sound (e.g., a transducer located below) and the other outputs reverse-phase high-frequency sound (e.g., a transducer located above), and the two sets of opposite-phase high-frequency sound are transmitted to the two second hole portions 5657 along the two acoustic paths 5655, respectively, and propagate outward through the two second hole portions 5657.

In some embodiments, two transducers of speakers (e.g., first speaker 5640, second speaker 5650) may be disposed in close proximity relative to each other along the same line, with one for outputting positive sound and the other for outputting negative sound. As shown in fig. 59B, the left side is a first speaker 5640, and the right side is a second speaker 5650. The two transducers 5643 of the first speaker 5640 each produce a set of equal amplitude, opposite phase low frequency sounds under the control of the controller. One of the transducers outputs normal low frequency sound and transmits to one of the first hole portions 5647 along a first acoustic path, and the other transducer outputs reverse low frequency sound and transmits to the other first hole portion 5647 along a second acoustic path. The two transducers 5653 of the second speaker 5650 each produce a set of high frequency sounds of equal amplitude and opposite phase under the control of the controller. One of the transducers outputs normal-phase high-frequency sound and transmits to one of the second hole portions 5657 along the third acoustic path, and the other transducer outputs inverted-phase high-frequency sound and transmits to the other of the second hole portions 5657 along the fourth acoustic path.

In fig. 59A and 59B, the dipole sound source pitch of the first speaker 5640 is d ₁ The dipole sound source spacing of the second speaker 5650 is d ₂ And d ₁ Greater than d ₂ . As shown in fig. 59B, the listening position (i.e., the position of the ear canal when the user wears the open earphone) may be located on the line of a set of dipole sound sources. In some alternative embodiments, the listening position may be any suitable position. For example, the listening position may be located on a circle centered on the center point of the dipole sound source.

Fig. 60-61B are schematic diagrams of acoustic paths shown according to some embodiments of the present description.

As described above, the frequency division of sound can be achieved by configuring the corresponding acoustic filter network by providing structures of sound tubes, sound cavities, acoustic resistances, etc. in the acoustic path. Fig. 60 to 61B are schematic diagrams showing the structure of dividing the frequency of the sound signal by the acoustic path.

As shown in fig. 60, the acoustic path may be formed by a series connection of one or more sets of lumen structures, with acoustic resistive material disposed in the lumen to adjust the acoustic impedance of the overall structure to achieve a filtering effect. In some embodiments, the crossover of sound may be achieved by band-pass or low-pass filtering the sound by adjusting the size of the structures and the acoustic resistive material in the lumen. As shown in fig. 61A, a structure of one or more sets of resonant cavities (e.g., helmholtz resonators) may be constructed in the acoustic path branching path, and the filtering effect may be achieved by adjusting the size and acoustic resistance materials of the respective structures. As shown in fig. 61B, a combination of lumen and resonant cavity (e.g., helmholtz resonator) structures may be configured in an acoustic path, and a filtering effect may be achieved by adjusting the dimensions of the structures and the acoustic resistive material.

In some embodiments, the acoustic path may act as an acoustic transmission structure for the open earphone, and a filtering structure may be disposed in the acoustic transmission structure, and the filtering structure may include a sound absorbing structure for absorbing sound in a target frequency range, thereby adjusting the sound effect of the open earphone in a spatial point (e.g., reducing high frequency leakage of the open earphone in a far field). The sound absorbing structure may include a resistive sound absorbing structure or a sound absorbing structure. The resistive sound absorbing structure may comprise a porous sound absorbing material or an acoustic gauze. The sound absorbing resistant structure may include, but is not limited to, perforated plates, microperforated plates, sheets, films, 1/4 wavelength resonance tubes, and the like, or any combination thereof. For further description of filtering structures (or sound absorbing structures) see fig. 75-86 and their associated description, which are not repeated here. In some embodiments, the filtering structure may absorb mid-to-high frequency sounds of a particular frequency range and be disposed in a corresponding acoustic transmission structure of the tweeter. For example, the filtering structure may be disposed in the acoustic transmission structure between the tweeter and the far earhole part to reduce the mid-high frequency sound of a specific frequency range output from the far earhole part, and avoid the interference enhancement of the mid-high frequency sound of the specific frequency range and the mid-high frequency sound of the same frequency range output from the near earhole part in the far field, thereby reducing the leakage sound of the open earphone in the far field in the specific frequency range. For another example, a filtering structure may be disposed in the acoustic transmission structure between the tweeter and the near-earhole portion to reduce mid-to-high frequency sounds within the specific frequency range output from the near-earhole portion, and to avoid interference enhancement in the far field between mid-to-high frequency sounds within the specific frequency range and mid-to-high frequency sounds within the same frequency range output from the far-earhole portion. For another example, filtering structures may be provided in the transmission structure between the tweeter and the near and far earhole portions, respectively, to better reduce leakage of mid-to-high frequency sounds in that particular frequency range in the far field. In some embodiments, the filtering structure may absorb low frequency sounds of a particular frequency range and be disposed in a corresponding acoustic transmission structure of the woofer. For example, a filtering structure may be provided in the acoustic transmission structure between the low frequency speaker and the far earhole part to reduce the low frequency sound of a specific frequency range output from the far earhole part, and avoid interference cancellation of the low frequency sound of the specific frequency range and the low frequency sound of the same frequency range output from the near earhole part in the near field, thereby increasing the volume of the open earphone in the near field (i.e., transferred to the user's ear) in the specific frequency range. In some embodiments, the filtering structure may further include sub-filtering structures that absorb different frequency ranges, for example, absorb middle and high frequency bands and low frequency bands, respectively, and are disposed in the acoustic transmission structure corresponding to the low frequency speaker and the acoustic transmission structure corresponding to the high frequency speaker, respectively, for absorbing sounds in the different frequency ranges.

Fig. 62A is an exemplary graph of leakage under the combined action of two sets of dipole sound sources according to some embodiments of the present disclosure.

Fig. 62A shows a sound leakage curve of an open earphone (e.g., open earphone 5300, open earphone 5600, open earphone 5800, etc.) under the combined action of two sets of dipole sound sources (a set of high-frequency dipole sound sources and a set of low-frequency dipole sound sources). The frequency division point of the two dipole sound sources in the figure is about 700 Hz.

The normalized parameter α is used as an index for evaluating the leakage volume (calculation of α is referred to as formula (4)), and as shown in fig. 62A, the leakage-reducing ability of the dipole sound source is stronger than that of the case of the single-point sound source. Further, with respect to an open earphone in which only one set of dipole sound sources is provided, high-frequency sound and low-frequency sound are output by the two sets of dipole sound sources, respectively, and the low-frequency dipole is causedThe spacing of the sub-sound sources is greater than the spacing of the high frequency dipole sound sources. In the low frequency range, by setting a large dipole-to-sound source spacing (d ₁ ) The near-field listening volume increment is larger than the far-field leaking volume increment, and higher near-field volume output in a low frequency band can be realized. Meanwhile, because the leakage sound of the dipole sound source is originally few in a low-frequency range, after the interval of the dipole sound source is increased, the leakage sound which rises slightly can still be kept at a lower level. In the high frequency range, by setting a small dipole-to-sound source spacing (d ₂ ) The problems of low high-frequency leakage-reducing cut-off frequency and narrow leakage-reducing audio frequency range are solved. Therefore, the open earphone provided in the embodiments of the present specification is configured by setting the dipole sound source spacing d in the low frequency band ₁ Setting dipole sound source distance d in high frequency band ₂ A stronger sound leakage reduction capability than a single point sound source, and a set of dipole sound sources, can be obtained.

In some embodiments, the low frequency and high frequency sounds actually output by the open earphone may differ from those shown in fig. 62A, subject to factors such as the actual circuit filtering characteristics, transducer frequency characteristics, and acoustic channel frequency characteristics. Furthermore, the low-frequency, high-frequency sound may produce a certain overlap (aliasing) of the frequency bands around the crossover point, resulting in that the total leakage of the open earphone does not have abrupt changes at the crossover point as shown in fig. 62A, but rather gradual changes and transitions of the frequency bands around the crossover point, as indicated by the solid line in fig. 62A. It will be appreciated that these differences do not affect the overall sound leakage reduction effect provided by the embodiments of the present description.

Fig. 62B is a normalized graph of leakage shown in accordance with some embodiments of the present description. In some embodiments, the sensitivity of the human ear to different frequency sounds is not the same. For practical listening situations, it is often necessary to ensure that the human ear perceives the same loudness of sounds of different frequencies. Under such a demand, the volume (sound pressure value) of the output at different frequencies is made different. As shown in fig. 62B, by setting the low-frequency dipole sound source and the high-frequency dipole sound source with different pitches, different sound leakage reduction effects can be achieved. The actual leakage is shown in the total leakage curve in fig. 62B, where the frequency bands of the high and low frequency sounds overlap to some extent near the crossover point, so that the total leakage curve is in a gradual change and transition form in the frequency band.

In some embodiments, the listening and leaking sound produced by a dipole sound source is related to the amplitude of the two point sound sources. For example, a plot of the listening and leaking of a dipole sound source at a particular frequency as a function of the amplitude ratio of two point sound sources is shown in fig. 63A. The amplitude ratio referred to in this specification is the ratio of the larger amplitude to the smaller amplitude of two point sound sources. In fig. 63A, a solid line represents a change in the near-field listening of a dipole sound source with respect to amplitude, and a broken line represents a change in the far-field leakage of the dipole sound source with respect to amplitude. The abscissa represents the amplitude ratio between dipole sound sources, and the ordinate represents the magnitude of sound volume. And to better represent the relative change of the listening and the leaking sound, the sound volume is normalized by taking the leaking sound volume as a reference, namely the ordinate reflects the ratio of the actual volume to the leaking sound volume (namely |P|/|P) _far I) size.

At this specific frequency, when the amplitude ratio between the two point sound sources increases within a certain range, the increase amplitude of the listening volume of the dipole sound source may be significantly larger than the increase amplitude of the leakage volume. As shown in FIG. 63A, when the amplitude ratio A between two point sound sources ₂ /A ₁ When the volume of the listening sound is changed within the range of 1-1.5, the increase amplitude of the volume of the leaking sound is obviously larger than that of the leaking sound. That is, in this case, the larger the amplitude ratio between the two point sound sources, the more advantageous the dipole sound source reduces the far-field leakage sound volume while producing a higher near-field listening sound volume. In some embodiments, as the amplitude ratio between two point sound sources increases further, the slope of the normalized curve for the listening volume gradually tends to 0, and the normalized curve for the leakage volume gradually tends to be parallel, indicating that the increase in listening volume is substantially the same as the increase in leakage volume. As shown in FIG. 63A, when the amplitude ratio A between two point sound sources ₂ /A ₁ When the change is made within a range larger than 2, the increase amplitude of the listening volume is substantially the same as the increase amplitude of the leakage volume.

In some embodiments, to ensure that a dipole sound source can produce a greater near-field listening volume and a smaller far-field leakage volume, the amplitude ratio between the two point sound sources may be made to be within a suitable range. In some embodiments, it is assumed that the low frequency dipole sound source (e.g., the two first hole portions 5647 of the first speaker 5640) has a first amplitude ratio between the low frequency sound having a larger amplitude and the low frequency sound having a smaller amplitude, and the high frequency dipole sound source (e.g., the two first hole portions 5657 of the second speaker 5650) has a second amplitude ratio between the high frequency sound having a larger amplitude and the high frequency sound having a smaller amplitude, and the first amplitude ratio may be at least 2 times or more the second amplitude ratio. In some embodiments, to ensure that the dipole sound source is capable of producing a greater near-field listening volume and a smaller far-field leakage volume, the first amplitude ratio may be no less than 1, the second amplitude ratio may be no greater than 5, and the first amplitude ratio is greater than the second amplitude ratio. For example, the first amplitude ratio may be in the range of 1-3 and the second amplitude ratio may be in the range of 1-2.

In some embodiments, the listening and leaking sound produced by a dipole sound source is related to the phase of the two point sound sources. For example, a plot of listening and leaking of a dipole sound source at a specific frequency as a function of the phase difference between two point sound sources is shown in fig. 63B. Similar to fig. 63A, in fig. 63B, a solid line represents a change curve of near-field listening of a dipole sound source with a phase difference, and a broken line represents a change curve of far-field leakage of the dipole sound source with a phase difference. The abscissa indicates the phase difference between two point sound sources, and the ordinate indicates the magnitude of sound volume. And to better represent the relative change of the listening and the leaking sound, the sound volume is normalized by taking the leaking sound volume as a reference, namely the ordinate reflects the ratio of the actual volume to the leaking sound volume (namely |P|/|P) _far I) size.

At the specific frequency, a peak is formed by a normalized curve corresponding to the listening volume of the dipole sound source according to the change of the phase difference between the two point sound sources. As shown in fig. 63B, the absolute value of the phase difference between the two point sound sources corresponding to the peak is about 170 degrees. At this peak, the dipole sound source has the largest normalized listening volume, i.e. it means that the dipole sound source can produce a larger listening volume if the listening volume is kept unchanged, or a smaller listening volume if the listening volume is kept unchanged.

It should be noted that, at different frequencies, the phase difference corresponding to the peak of the normalized curve of the volume of the listening may be shifted. In some embodiments, to ensure that a dipole sound source is capable of producing a greater near-field listening volume and a smaller far-field leakage volume over a range of sound frequencies (e.g., over a range of frequencies audible to the human ear), the absolute value of the phase difference between the dipole sound sources may be made to lie within a range. In some embodiments, the absolute value of the phase difference between dipole sound sources may be made to be in the range of 180-120 degrees. For example, the absolute value of the phase difference between the dipole sound sources may be made within a range of 180 degrees to 160 degrees.

To further describe the effect of the amplitude ratio between dipole sound sources on the output sound of the open earphone, the following description is given by two sets of dipole sound sources shown in fig. 64A.

In fig. 64A, the left dipole sound source represents a dipole sound source equivalent to two holes (for example, first hole 5647) corresponding to a low-frequency speaker (for example, first speaker 5640) (output frequency ω ₁ A low-frequency sound of (a), the right dipole sound source represents a dipole sound source equivalent to two hole portions (e.g., second hole portions 5657) corresponding to the high-frequency speaker (e.g., second speaker 5650) (output frequency is ω) ₂ High frequency sound of (a). For simplicity, it is assumed that the high frequency dipole sound source and the low frequency dipole sound source have the same spacing d therebetween.

The high frequency dipole sound source and the low frequency dipole sound source may output a set of opposite phase high frequency sounds and a set of opposite phase low frequency sounds, respectively. The amplitude ratio of the point sound source with larger amplitude to the point sound source with smaller amplitude in the low-frequency dipole sound source is A ₁ The amplitude ratio of the larger amplitude point sound source to the smaller amplitude point sound source in the high-frequency dipole sound source is A ₂ And A is ₁ ＞A ₂ . In FIG. 64A, the listening position is located on a straight line where the high frequency dipole sound source is located and is perpendicular to the line of one of the point sound sources in the low frequency dipole sound sourceIn the straight line where the low frequency dipole sound source is located. It should be understood that the choice of listening positions is merely exemplary and is not limiting of the present description. In some alternative embodiments, the listening position may be any suitable position. For example, the listening position may be located at the center line of the dipole sound source.

In some embodiments, the desired amplitude ratio may be obtained by adjusting the structural parameters of the different components in the open earphone. For example, the amplitude of the sound output at the hole portion may be changed by adjusting the acoustic impedance of the acoustic path (e.g., adding a damping material such as tuning net, tuning cotton, or the like in the acoustic path 5645 or 5655 to change the acoustic impedance thereof). Assuming that the acoustic impedance ratio of the front and rear chambers of the tweeter is a first acoustic impedance ratio, the acoustic impedance ratio of the front and rear chambers of the tweeter is a second acoustic impedance ratio, in some embodiments, the first and second acoustic impedance ratios may be any value, and the first acoustic impedance ratio may be greater than, less than, or equal to the second acoustic impedance ratio. In some embodiments, the first acoustic impedance ratio may be no less than 0.1 and the second acoustic impedance ratio may be no greater than 3. Preferably, the first acoustic impedance ratio and the second acoustic impedance ratio may be in the range of 0.8-1.2.

In some embodiments, the acoustic impedance of the acoustic path may be changed by adjusting the tube diameter of the acoustic tube corresponding to the acoustic path in the open earphone, so as to achieve the purpose of adjusting the sound amplitude at the hole portion. In some embodiments, the ratio of the tube diameters of the two sound guides (the ratio of the tube diameter of the smaller-radius sound guide to the larger-radius sound guide) in the woofer may be set in the range of 0.8-1.0. Preferably, the tube diameters of the two sound guide tubes in the woofer may be set to be the same.

In some embodiments, the internal friction or viscous force of the medium in the sound guide tube can have a large influence on the propagation of sound, and too small a tube diameter of the sound guide tube can cause excessive loss of sound and reduce the volume of sound at the sound guide hole. To more clearly describe the effect of the tube diameter of the sound guide on the sound volume, the tube diameters of the sound guide at different frequencies will be described below in conjunction with fig. 64B and 64C.

Fig. 64B and 64C are graphs of sound guide parameters versus sound frequency variation according to some embodiments of the present description. Fig. 64B shows the minimum values of the sound guide tube diameters corresponding to different sound frequencies. Wherein, the ordinate is the minimum value of the pipe diameter of the sound guide pipe, the unit is centimeter (cm), and the abscissa is the frequency of sound, and the unit is hertz (Hz). As shown in FIG. 64B, when the sound frequency is 20 Hz-20 kHz, the pipe diameter (or equivalent radius) of the sound guide pipe should be not less than 3.5mm. When the sound frequency is 60 Hz-20 kHz, the pipe diameter (or equivalent radius) of the sound guide pipe should not be less than 2mm. Therefore, in order to ensure that the sound within the audible range of the human ear output by the earphone is not excessively lost due to the too small sound guide tube, the tube diameter of the sound guide tube corresponding to the acoustic path in the earphone should be not less than 1.5mm, preferably not less than 2mm.

In some embodiments, if the sound guide tube is too large in diameter, when the transmitted sound is greater than a certain frequency, high order waves are generated in the sound guide tube, thereby affecting the sound that eventually propagates outward from the sound guide hole. Therefore, the design of the sound guide tube needs to ensure that high-order waves are not generated in the frequency range of the sound to be transmitted, and only plane waves propagating along the direction of the sound guide tube exist. Fig. 6C shows the maximum values of the sound guide tube diameters corresponding to different upper cut-off frequencies. Wherein, the abscissa is the maximum value of the pipe diameter of the sound guide pipe, the unit is centimeter (cm), and the ordinate is the cut-off frequency of sound transmission, and the unit is kilohertz (kHz). As shown in fig. 64C, when the upper limit frequency of sound is 20kHz, the pipe diameter (or equivalent radius) of the sound guide pipe should be not more than 5mm. When the upper limit frequency of sound is 10kHz, the pipe diameter (or equivalent radius) of the sound guide pipe should be not more than 9mm. Therefore, in order to ensure that the earphone does not generate high-order waves when outputting sound in the audible range of the human ear, the pipe diameter of the sound guide pipe corresponding to the acoustic path in the earphone should be made not more than 10mm, preferably not more than 8mm.

In some embodiments, the acoustic impedance of the acoustic path may be changed by adjusting the length of the acoustic pipe corresponding to the acoustic path in the open earphone, so as to achieve the purpose of adjusting the sound amplitude at the hole portion. The length and aspect ratio (length to diameter ratio) of the sound guide tube will have an effect on the transmitted sound. By way of illustration only, the sound pressure of the sound transmitted by the sound guide tube and the length and aspect ratio of the sound guide tube satisfy equation (5):

|P|＝|P ₀ |exp(-βL)， (5)

Wherein P is ₀ For sound pressure of the sound source, L is length of the sound guide tube, and β satisfies:

wherein a is the radius of the catheter and c ₀ For the propagation speed of sound, ω is the angular frequency of the sound wave, η/ρ ₀ Is the dynamic viscosity of the medium. Under different sound guide pipe diameters, the length and the length-diameter ratio of the sound guide pipe are different in attenuation degree of sound with different frequencies.

In some embodiments, when the pipe diameter of the sound guide pipe is fixed, the greater the length (length-diameter ratio) value of the sound guide pipe, the greater the attenuation generated by the sound guide pipe on the sound transmitted in the pipe, and the greater the attenuation degree of the sound in the high frequency band and the lower frequency band. Therefore, in order to ensure that the sound attenuation of the open earphone is not so great as to affect the volume of the listening, the aspect ratio of the sound guide tube corresponding to the acoustic path in the open earphone should be not more than 200, preferably not more than 150.

In some embodiments, due to the interaction between the sound guide tube and the orifice radiation impedance, the sound of a particular frequency transmitted in the sound guide tube may form standing waves therein, resulting in the output sound forming peaks/valleys at certain frequencies, affecting the output effect of the sound. The length of the sound guide tube may affect the formation of standing waves. For a clearer description, the relative magnitudes of sound pressures of sound output from sound guide tubes of different lengths are shown in fig. 65A. As can be seen from fig. 65A, the longer the length of the sound guide tube, the lower the minimum frequency of peaks/valleys generated, and the greater the number of peaks/valleys. To reduce the influence of peaks/valleys on the sound output effect, the length of the sound guide tube may be adjusted to meet certain conditions. In some embodiments, the sound guide tube length may be no greater than 200mm, so that the output sound is relatively flat in the range of 20Hz-800 Hz. In some embodiments, the sound guide tube length may be no greater than 100mm, such that the output sound is flat without peaks and valleys in the 20Hz-1500Hz range. In some embodiments, the sound guide tube length may be no greater than 50mm, such that the output sound is flat without peaks and valleys in the 20Hz-3200Hz range. In some embodiments, the sound guide tube length may be no greater than 30mm, such that the output sound is flat without peaks and valleys in the 20Hz-5200Hz range.

Fig. 65B is a graph of experimental test leakage reduction effects according to some embodiments of the present disclosure. The frequency division point of the low frequency and the high frequency is selected to be 1.2kHz, the radius of the sound guide tube is 2mm, and the length of each sound guide tube is 105mm. The output sound pressure of the earphone is measured at a position 10mm away from the device along the connecting line direction of the dipole sound source by using a microphone and is used as the listening sound pressure of the human ear, and the sound pressure is measured at a position 150mm away from the earphone along the perpendicular line direction of the connecting line of the dipole sound source and is used as the leakage sound pressure of the earphone. For reference, 0dB is the leakage volume of one point sound source. From the result of practical test, the scheme of a group of dipole sound sources has larger leakage-reducing volume in the low frequency band, but the frequency range of leakage reducing sound is narrower, and the leakage sound is larger than that of a point sound source in the range above about 2 kHz. The scheme comprising a low-frequency dipole sound source and a high-frequency dipole sound source has certain sound leakage reducing capability in the low frequency band before the frequency division point, and the sound leakage reducing capability in the high frequency band after the frequency division point is stronger than that of the scheme of a group of dipole sound sources. Meanwhile, the frequency range of the leakage sound can be wider, and the leakage sound can be reduced within the range of 100Hz-9 kHz.

In some embodiments, the length and the pipe diameter (i.e., radius) of the sound guide pipe can be adjusted simultaneously so that they respectively meet certain conditions. In some embodiments, in order to ensure that the earphone does not generate high-order waves when outputting sound in the audible range of human ears, and the output sound is flat and has no peak valley in the specific frequency range, so as to ensure the output effect of the earphone, the pipe diameter of the sound guide pipe may be not less than 0.5mm, and the length of the sound guide pipe may be not more than 150mm.

In some embodiments, setting of the dipole sound source amplitude ratio may be achieved by adjusting the structure of the hole portion in the open earphone. For example, the two holes corresponding to each speaker of the open earphone may be respectively set to different sizes, areas, shapes, and/or the like. For another example, the hole portions corresponding to different speakers of the open earphone may be provided in different numbers.

In some embodiments, when speakers (e.g., first speaker 5640, second speaker 5650) output sound through two hole portions (e.g., two first hole portions 5647, two second hole portions 5657), the two hole portions may output sound having the same or different phases. For example, considering that when low-frequency sounds having different phases are output from the two first hole portions 5647, when the absolute value of the phase difference approaches 170 degrees, according to the description of fig. 63B, the open earphone can produce a larger listening volume while keeping the far-field leakage volume unchanged. As another example, considering that when high-frequency sounds having different phases are output from the two second hole portions 5657, when the absolute value of the phase difference approaches 170 degrees, according to the description of fig. 63B, the open earphone can generate a smaller leakage sound volume while keeping the near-field listening sound volume unchanged. Therefore, by reasonably designing the structures of the electronic frequency division module, the transducer, the acoustic path or the hole part, the phase difference between the high-frequency sounds at the hole part corresponding to the high-frequency speaker and the phase difference between the low-frequency sounds at the hole part corresponding to the low-frequency speaker meet certain conditions, and the open earphone can have better sound output effect.

To further describe the effect of the phase difference between the dipole sound sources on the output sound of the open earphone, the following description will be given by way of two sets of dipole sound sources shown in fig. 66.

In fig. 66, the left dipole sound source represents a dipole sound source equivalent to two holes corresponding to a low-frequency speaker, and the right dipole sound source represents a dipole sound source equivalent to two holes corresponding to a high-frequency speaker. For simplicity, it is assumed that the high frequency dipole sound source and the low frequency dipole sound source have the same spacing d therebetween.

For simplicity, the high-frequency dipole sound source and the low-frequency dipole sound source may output a set of high-frequency sound and low-frequency sound having equal amplitudes and having a certain phase difference, respectively. In some embodiments, by properly designing the phase difference between the high frequency dipole sound sources and the phase difference between the low frequency dipole sound sources, the dipole sound sources can obtain stronger sound leakage reduction capability than the single point sound sources. In fig. 66, by way of example only, the listening position is located on a straight line where the high frequency dipole sound source is located, and the line connecting one of the point sound sources with the low frequency dipole sound source is perpendicular to the straight line where the low frequency dipole sound source is located.

As shown in fig. 66, the far-ear sound source (i.e., the point sound source on the upper left side) in the low-frequency dipole sound source has a phase difference of the near-ear sound source (i.e., the point sound source on the lower left side) with respect to the far-ear sound source The far-ear sound source (i.e., the point sound source on the upper right side) in the high-frequency dipole sound source has a phase difference of +.>And->And->The method meets the following conditions:

in some embodiments, the desired phase difference may be obtained by adjusting the structural parameters of the different components in the open earphone. For example, the sound path between the speaker and the aperture in the open earphone may be adjusted to change the phase of the output sound at the aperture. In some embodiments, the sound Cheng Bi of the two sound guides corresponding to the low frequency speaker may be in the range of 0.4-2.5 and the sound paths of the two sound guides corresponding to the high frequency speaker may be the same.

In some embodiments, the phase difference between two apertures on the open earphone corresponding to one speaker may be adjusted by adjusting the sound signal input into the speaker. In some embodiments, the absolute value of the phase difference of the low-frequency sound output through the two first hole portions may be smaller than the absolute value of the phase difference of the high-frequency sound output through the two second hole portions. In some embodiments, the phase difference of the low frequency sound outputted through the two first hole parts may be in the range of 0 degrees to 180 degrees, and the phase difference of the high frequency sound outputted through the two second hole parts may be in the range of 120 degrees to 180 degrees. Preferably, the phase difference of the low-frequency sound outputted through the two first hole portions and the phase difference of the high-frequency sound outputted through the two second hole portions may be both 180 degrees.

Fig. 67-69B are exemplary graphs of leakage under the combined action of two sets of dipole sound sources according to some embodiments of the present disclosure.

As shown in fig. 67, by providing two sets of dipole sound sources having different amplitudes, a stronger sound leakage reduction capability than a single point sound source can be obtained. For example, the amplitude ratio of the low frequency dipole sound source is A ₁ The amplitude ratio of the high-frequency dipole sound source is A ₂ . In the low frequency band, the amplitude ratio of the dipole sound source is adjusted (e.g., A ₁ Set to a value greater than 1) the near-field listening delta is greater than the far-field listening delta, and a higher near-field volume in the low frequency band can be achieved. Meanwhile, because the far-field leakage sound of the dipole sound source is originally few in the low frequency band, after the amplitude ratio of the dipole sound source is adjusted, the leakage sound with a little rise can still be kept at a lower level. In the high frequency band, setting the sound source amplitude ratio of the dipole sound source to enable A to be ₂ Equal to or close to 1, a stronger leakage-reducing capability can be obtained in the high frequency band to meet the requirements of an open earphone with open ears. As can be seen from fig. 69A, a system consisting of two sets of dipole sound sources produces a total leakage that can be kept low below 7000Hz and less than the leakage produced by a single point sound source.

As shown in fig. 68, by providing two sets of dipole sound sources having different phase differences, a stronger sound leakage reduction capability than a single-point sound source can be obtained. For example, the low frequency dipole sound source has a phase difference ofThe phase difference of the high frequency dipole sound source is +.>In the low frequency band, the near-field listening increment is larger than the far-field listening increment after the phase difference of the dipole sound source is adjusted, so that higher near-field volume can be realized in the low frequency band. Meanwhile, because the far-field leakage sound of the dipole sound source is originally few in the low frequency band, after the phase difference of the dipole sound source is adjusted, the far-field leakage sound which rises slightly can still keep a lower level. In the high frequency band, the phase difference of the dipole sound source is set so that +.>Equal to or close to 180 degrees, stronger sound leakage reduction capability can be obtained in the high frequency band so as to meet the requirements of the open double-ear open earphone.

It should be appreciated that the overall drop-out curves in fig. 67 and 68 are ideal for illustrative purposes only. The actually output low-frequency sound and high-frequency sound are different from those of fig. 67 and 68, affected by factors such as the actual circuit filter characteristic, the transducer frequency characteristic, the acoustic channel frequency characteristic, and the like. It will be appreciated that these differences do not affect the overall sound leakage reduction effect provided by the embodiments of the present description.

Fig. 69A shows a sound leakage curve of the pipe diameter ratio of the dipole sound source. As shown in fig. 69A, the leakage reduction capability of the dipole sound source is better than that of the single-point sound source in a certain frequency range (for example, in the range of 800Hz-10 kHz). For example, when the pipe diameter ratio of the dipole sound source sound guide pipe is 1, the sound leakage reducing capability of the dipole sound source is strong. For another example, when the hole diameter ratio of the dipole sound source is 1.1, the sound leakage reduction capability of the dipole sound source is better than that of the single-point sound source in the range of 800Hz-10 kHz.

The drop leakage curves for different duct length ratios for a dipole sound source are shown in fig. 69B. As shown in fig. 69B, in the range of 100Hz-1kHz, adjusting the length ratio of the sound guide tube of the dipole sound source (the length ratio of the sound guide tube with longer length to the sound guide tube with shorter length), for example, the length ratio of 1, 1.05, 1.1, 1.5, 2, etc., can make the sound leakage reduction capability of the dipole sound source better than that of the single-point sound source. In the range of 1kHz-10kHz, the length ratio of the sound guide tube of the dipole sound source (the length ratio of the sound guide tube with longer length to the sound guide tube with shorter length) is regulated to be close to 1 (for example, the length ratio is 1), so that the sound leakage reduction capability of the dipole sound source is better than that of a single-point sound source.

Fig. 69C is a plot of the frequency response of a low frequency speaker and a high frequency speaker shown in accordance with some embodiments of the present description. In some embodiments, the low frequency dipole sound source and the high frequency dipole sound source are set using a low frequency speaker and a high frequency speaker, respectively. The frequency response characteristics of the speakers themselves are different, and the audio frequency bands to be output are also different. Typical woofer and tweeter frequency response curves are shown in fig. 69C, with the frequency bands of the output sound at the low and high frequency bands, respectively. The frequency division of the high-low frequency band can be realized by using the low-frequency loudspeaker and the high-frequency loudspeaker, so that the dipole sound source with high and low frequency is constructed for sound output and leakage reduction, and the frequency division of signals is not needed or the frequency division of signals by the front end is simplified. In some embodiments, each speaker may be a moving coil speaker, which has the characteristics of high low frequency sensitivity, large low frequency submergence depth, and small distortion. In some embodiments, each speaker may be a moving iron speaker, which has the characteristics of small size, high sensitivity, and large high frequency range. In some embodiments, each speaker may be an air conduction speaker or a bone conduction speaker. In some embodiments, each speaker may include an air conduction speaker, a bone conduction speaker, an underwater acoustic transducer, an ultrasonic transducer, or the like.

In some embodiments, when a certain condition (e.g., spacing, amplitude, phase) is satisfied between the two first hole portions of the first speaker and the two second hole portions of the second speaker, the sound leakage reducing effect of the open earphone in the far field can be further improved. For example, the two first hole portions and the second hole portion output sound of a certain frequency range in common, that is, there is an overlapping frequency range of high-frequency sound and low-frequency sound. Within this overlapping frequency range, the sound generated by the two first hole portions and the two second hole portions can be regarded as sound generated by the four point sound sources together. When certain conditions are met among the four point sound sources, the open earphone can generate higher listening volume in the near field and generate smaller leaking volume in the far field. To further describe the influence of the four-point sound source on the output sound of the open earphone, two sets of four-point sound sources shown in fig. 70A and 70B are explained below.

Fig. 70A and 70B are schematic diagrams of four-point sound sources shown according to some embodiments of the present description.

In fig. 70A and 70B, symbols "+" and "-" correspond to the hole portions on the open earphone and the phases of sounds generated thereby, respectively. The two first hole portions 5647 correspond to the same speaker (for example, the first speaker 5640) and can be equivalent to a first dipole sound source, and the two second hole portions 5657 also correspond to the same speaker (for example, the second speaker 5650) and can be equivalent to a second dipole sound source. When the first dipole sound source and the second dipole sound source output sound of the same frequency together, the two sets of dipole sound sources may together constitute a four-point sound source. For a clearer description, the figure also shows the ear E of the user wearing the device.

The two first hole portions 5647 may have a first distance d therebetween ₁ The two second hole portions 5657 may have a second distance d therebetween ₂ . In some embodiments, the first pitch and the second pitch may be any value, and the first pitch is greater than the second pitch. For the content of the first pitch and the second pitch, reference may be made elsewhere in this specification.

In some embodiments, the four apertures (i.e., the two first apertures 5647 and the two second apertures 5657) may be open at different locations of the open earphone. For example only, the first aperture 5647 and the second aperture 5657 may be open on the same or different sides of the housing of the open earphone. The four hole portions may be arranged along one straight line or a plurality of straight lines on the housing. As shown in fig. 70A or 70B, the two first hole portions 5647 may be arranged at intervals along the first direction, and the two second hole portions 5657 may be arranged at intervals along the second direction. The first direction is parallel to the second direction.

In some embodiments, a particular relationship may be satisfied between the location of the aperture and the user's ear when the user wears the open earphone 7000. For example, with the listening position (i.e., the user's ear) as the vertex, the angle formed by the two first hole portions 5647 with the listening position (i.e., the angle between vectors directed from the listening position to the two first hole portions 5647, respectively) may be no greater than 150 degrees, and the angle between the two second hole portions 5657 with the listening position (i.e., the angle between vectors directed from the listening position to the two second hole portions 5657, respectively) may be no less than 0 degrees. In some embodiments, the two first apertures 5647 may form an angle with the listening position of no more than 100 degrees and the two second apertures 5657 may form an angle with the listening position of no less than 10 degrees. The relationship between the more porous portions and listening positions may be found elsewhere in this specification (as in fig. 71 and its associated description).

It will be appreciated that the aperture may be provided at any reasonable location on the open earphone, and this description is not intended to be limiting. For example, one of the first hole portions 5647 (also called a near-ear first hole portion) may be opened at a position closer to the ear than the other (also called a far-ear first hole portion), and one of the second hole portions 5657 (also called a near-ear second hole portion) may be opened at a position closer to the ear than the other (also called a far-ear second hole portion). In some embodiments, the near-ear aperture portions (e.g., near-ear first aperture portion 5647, near-ear second aperture portion 5657) may be open on a side of the housing of the open earphone facing the user's ear, and the far-ear aperture portions (e.g., far-ear first aperture portion 5647, far-ear second aperture portion 5657) may be open on a side of the housing of the open earphone facing away from the user's ear.

In some embodiments, the sounds output by the first dipole sound source through the two first hole portions 5647 may have a first phase difference, and the sounds output by the second dipole sound source through the two second hole portions 5657 may have a second phase difference. In some embodiments, the absolute value of the first phase difference may be in the range of 160-180 degrees and the absolute value of the second phase difference may be in the range of 160-180 degrees. In some embodiments, the absolute value of the second phase difference may be greater than the absolute value of the first phase difference. In some embodiments, the absolute value of the second phase difference may be in the range of 170-180 degrees and the absolute value of the first phase difference may be in the range of 160-180 degrees. In some embodiments, the phase difference between the normal phase sound and the reverse phase sound may be 180 degrees. For example, as shown in fig. 70A, the open earphone 7000 outputs a normal phase sound through a near-ear first hole portion of the first hole portions 5647, and outputs an inverted phase sound through a far-ear first hole portion of the first hole portions 5647; and outputting normal phase sound through the near-ear second hole portions in the second hole portions 5657, and outputting reverse phase sound through the far-ear second hole portions in the second hole portions 5657.

In some embodiments, the open earphone may have a third phase difference between sound output from a hole portion of the two first hole portions that is closer to the user's ear (i.e., the near-ear first hole portion) and sound output from a hole portion of the two second hole portions that is closer to the user's ear (i.e., the near-ear second hole portion). In some embodiments, the third phase difference may have a value of 0. For example, as shown in fig. 70A, the open earphone 7000 outputs a normal phase sound through the near-ear first hole portion of the first hole portions 5647, and also outputs a sound in normal phase through the near-ear second hole portion of the second hole portions 5657, and the two sets of sounds have the same phase or approximately the same phase (for example, the absolute value of the phase difference of the two sets of sounds is in the range of 0 degrees to 10 degrees). The open earphone 7000 outputs the inverted sound through the far-ear first hole portion of the first hole portions 5647 and also outputs the inverted sound through the far-ear second hole portion of the second hole portions 5657, both of which are opposite in phase to the sound output from the near-ear first hole portion and the near-ear second hole portion (180 degrees out of phase). In some embodiments, the absolute value of the third phase difference may be in the range of 160-180 degrees. Preferably, the absolute value of the third phase difference may be 180 degrees.

For example, as shown in fig. 70B, the open earphone outputs an inverted sound through a near-ear first hole portion of the first hole portions 5647, and outputs a normal sound through a near-ear second hole portion of the second hole portions 5657, with the phase difference between the two sets of sound signals being 180 degrees. The far-ear first hole portion of the first hole portions 5647 through which the open earphone passes outputs normal-phase sound, which is opposite in phase to the sound output through the near-ear first hole portion of the first hole portions 5647 (180 degrees out of phase). The sound output from the open earphone through the far ear second hole portion in the second hole portion 5657 is in anti-phase with the sound output from the near ear second hole portion in the second hole portion 5657 in opposite phase (180 degrees out of phase).

Further, the arrangement between the upper hole portions of the open earphone may affect the sound transmission of the open earphone in different directions. In some embodiments, the line connecting the two first holes 5647 of the open earphone, which is farther from the user's ear, to the two second holes, which is closer to the user's ear, is directed to the area where the user's ear is located. For example, in fig. 70A and/or 70B, the line connecting the distal ear first aperture portion of the first aperture portion 5647 and the proximal ear second aperture portion of the second aperture portion 5657 (dashed lines in the figures) may be directed toward the user's ear E or the region where it is located (i.e., the region where the listening position is located). In this case, the sound pressure of the sound transmitted by the open earphone in the direction of the broken line (i.e., the direction pointing toward the user's ear E) may be higher than the sound pressure of the sound transmitted in the other direction (e.g., the direction perpendicular to the broken line in the figure). In some embodiments, the line (i.e., the dashed line in fig. 70A and/or 70B) is at an angle of no more than 90 degrees from the line connecting the two first hole portions 5647. In some embodiments, the line is at an angle of no more than 90 degrees from the line of the two second hole portions 5657.

For convenience of description, the case where the sounds output from the two near-ear point sound sources of the four-point sound source shown in fig. 70A have the same phase, and the sounds output from the two far-ear point sound sources also have the same phase is also referred to as phase pattern 1. In fig. 70B, the sounds output from two sets of near-ear point sound sources of the four-point sound source have opposite phases, and the sounds output from two sets of far-ear point sound sources have opposite phases, which is also referred to as phase pattern 2. In some embodiments, phase pattern 2 and phase pattern 1 have different leakage reduction effects. For more details on the leakage reduction capability of an open earphone containing a four-point sound source, see elsewhere in this specification (e.g., fig. 73 and its associated description).

In some embodiments, the open headphones may control the phase of sound output at different aperture portions, respectively. For example, the sound generated by the first speaker 5640 is output at two first hole portions 5647, and the sound generated by the second speaker 5650 is output at two second hole portions 5657. The phase of the electrical signals input into the two speakers can be adjusted in the open earphone so that the output sound at the four hole portions can be switched between the phase mode 1 and the phase mode 2.

Fig. 71 is a schematic diagram of dipole sound sources and listening positions shown according to some embodiments of the present description.

In some embodiments, placing the two point sources of the dipole sound source in different positions relative to the listening position may cause the open earphone to produce different near-field listening effects. A schematic of the relationship of dipole sound sources to listening positions is shown in fig. 71. Wherein "+" and "-" respectively exemplify point sound sources outputting sounds of opposite phases, and "+" represents a positive phase, "-" represents an opposite phase, d represents a spacing between dipole sound sources, P _n Representing the listening position. In addition, for convenience of comparison, one of the point sources (e.g., the normal phase point source) of the dipole source in the figure and the listening position P ₁ Point to P ₅ The distances of the points are the same, namely, the listening position points are equivalent to being uniformly distributed on a circle taking the sound source of the point as the center of the circle. P (P) ₁ Point and P ₅ The point is positioned on the connecting line of two point sound sources of the dipole sound source, P ₃ The line connecting the normal point sound source is perpendicular to the line connecting the dipole sound sources. For a clearer description, the association of the dipole sound source listening volume and listening position will be described with reference to fig. 71 and 72. The average value of sound pressure amplitude values of each point on a spherical surface with the center of a dipole sound source as the center of a circle and the radius of 40cm is taken as the value of sound leakage. And in order to better represent the relative changes of the listening and the leakage, normalization processing is performed on the listening and the leakage in fig. 72.

The two point sound sources of the dipole sound source corresponding to fig. 71 and 72 have the same amplitude and opposite phases. When the sound frequency is constant, the angle between the dipole sound source and the listening position is different, and the volume of the generated listening sound is different (normalized volume is different). When the distance difference between the two point sound sources in the dipole sound source and the listening position is large, the open earphone can generate a large listening volume. As shown in fig. 72, when the listening position is at P ₁ In this case, the point sound source and listening position P are outputted in the opposite phase from the dipole sound source ₁ Distance of (2)Recently, the dipole sound source is at P ₁ The positive and negative sounds produced at this point cancel very little, so that the dipole sound source has the greatest volume of listening. Similarly, for listening position P ₂ 、P ₄ 、P ₅ Because a certain distance difference exists between the distance between the point sound source outputting the normal phase and the listening position in the dipole sound source and the distance between the point sound source outputting the reverse phase and the listening position, the cancellation of the normal phase and the reverse phase sound output by the dipole sound source is smaller, and the dipole sound source has larger listening volume. The open earphone produces a smaller volume of listening when the two point sources in the dipole source are close in distance to the listening position. For example, in fig. 72, when the listening position is at P ₃ At this time, the point sound source and listening position P due to the positive phase are output ₃ Point sound source and listening position P of opposite phase of output ₃ The distance of the dipole sound source is closer, the effect of the opposite phase cancellation of the sound is more obvious, and the volume of the sound of the dipole sound source is smaller.

From the above, it is known that when the positional relationship between the dipole sound source and the listening position satisfies a certain condition, the open earphone can have a higher listening volume. In practical application, the position of the hole part can be adjusted to improve the near-field listening volume generated by the dipole sound source. In some embodiments, the two hole portions in the dipole sound source are spaced less than 180 degrees, preferably no more than 90 degrees, from the listening position. The space included angle is an included angle formed by a space connecting line of the hole part and the listening position by taking the listening position as a vertex. In some embodiments, if the four-point sound source on the open earphone contains a set of high frequency dipole sound sources and a set of low frequency dipole sound sources, the two hole portions of the two sets of dipole sound sources may be arranged in different ways. For example, in order to increase the near-field listening volume, two hole portions of a low-frequency (or high-frequency) dipole sound source may be arranged in such a manner that the dipole sound source in fig. 71 is located such that the listening position (i.e., the user's ear) is located at P ₁ Or P ₅ . At this time, when the user wears the open earphone, the line connecting the two hole portions of the low frequency (or high frequency) dipole sound source is directed in the direction in which the user's ears are located.

In some embodimentsIn an example, the distances between two point sound sources of a dipole sound source are different, the positional relationship between the two point sound sources and the listening position is different, and the listening volume change rule is also different. For example, when the listening position is P in FIG. 71 ₁ 、P ₃ When the position (and the nearby position and the axisymmetric position along the connecting line of the two-point sound sources) is increased, the normalized listening volume is increased along with the increase of the distance d between the dipole sound sources, and the increment of the listening volume is larger than that of the leaking sound volume. In practical applications, an increase in listening volume can be achieved by increasing the dipole sound source spacing d without a significant increase in leakage volume. In particular, when the listening position is at P ₁ When the distance d is increased, the volume of the leakage sound is correspondingly increased, but the increment of the leakage sound is not larger than the increment of the listening sound. When the listening position is P ₂ 、P ₄ 、P ₅ When the position (and the nearby position thereof and the axisymmetric position along the two-point sound source connecting line) is increased, the normalized listening volume is reduced along with the increase of the dipole sound source distance d. In practical applications, enhancement of the leakage-reducing effect can be achieved by decreasing the dipole sound source spacing d. In particular, when the dipole sound source spacing d is reduced, the volume of the listening sound is also reduced, but the reduction is smaller than the leakage reduction.

Through the above, the listening volume and the sound leakage reduction capability of the dipole sound source can be improved by adjusting the distance between the dipole sound sources and the position relationship between the dipole sound sources and the listening position. Preferably, when the listening position is P ₁ 、P ₃ The dipole sound source spacing can be increased to obtain a larger listening volume when the location (and its vicinity, and its axisymmetric location along the two-point sound source connection line) is located. More preferably, the listening position is P ₁ The dipole sound source spacing can be increased to obtain a larger listening volume when the location (and its vicinity, and its axisymmetric location along the two-point sound source connection line) is located. Preferably, the listening position is P ₂ 、P ₄ 、P ₅ The distance between two sound sources can be reduced when the sound sources are positioned (and the positions nearby the sound sources and the positions along the connecting line axisymmetric positions of the two sound sources) so as to obtain better sound leakage reduction capability.

Fig. 73A and 73B are exemplary graphs of leakage under the combined action of two sets of dipole sound sources according to some embodiments of the present description.

As shown in fig. 73A, setting the dipole sound source can obtain a stronger sound leakage reduction capability than the single-point sound source. Preferably, two sets of dipole sound sources (a first dipole sound source and a second dipole sound source as shown in fig. 70A and 70B) are provided to output sounds having opposite phases, respectively, and a near-ear point sound source of the two sets of dipole sound sources outputs sounds having opposite phases (i.e., phase pattern 2), a stronger sound leakage reduction capability can be obtained than a case where one set of dipole sound sources (e.g., only the first dipole sound source or the second dipole sound source is included). For illustrative purposes only, the leakage of frequencies overlapping between two sets of dipole sound sources in the range of 100Hz-10000Hz is shown in fig. 73A. Specifically, in the overlapping frequency ranges, it can be considered that the far-field leakage sound generated by the second dipole sound source and the far-field leakage sound generated by the first dipole sound source interfere with each other in the four-point sound source so that the far-field leakage sound generated by the first dipole sound source or the second dipole sound source is reduced (i.e., the leakage sound corresponding to the phase pattern 2 in the figure is lower than the leakage sound generated by the first dipole sound source or the second dipole sound source only, thereby explaining that the leakage sound interference generated by the two dipole sound sources is eliminated). In phase mode 1, i.e. when near-ear point sound sources of the two sets of dipole sound sources output sounds with the same phase, the sound output device has a leakage reduction capability between only the first dipole sound source or the second dipole sound source. In this case, it can be considered that the far-field leakage sound generated by the second dipole sound source and the far-field leakage sound generated by the first dipole sound source interfere with each other in the four-point sound source, so that the far-field leakage sound generated by the first dipole sound source is reduced (i.e., the leakage sound corresponding to the phase pattern 1 in the figure is lower than the leakage sound when only the first dipole sound source is present, thereby explaining that the leakage sound generated by the second dipole sound source interacts with the leakage sound generated by the first dipole sound source, and the leakage sound generated by the first dipole sound source alone is suppressed).

Fig. 73B shows a drop-off sound curve at a different two-set dipole sound source pitch ratio when a four-point sound source (two-set dipole sound source) is set to phase mode 2. When the ratio of the first dipole sound source spacing D to the second dipole sound source spacing D is within a certain range, the four-point sound source can obtain stronger sound leakage reduction capability. For example, as shown in fig. 73B, when the ratio d1/d2 of the first dipole sound source spacing d1 to the second dipole sound source spacing d2 is 1, or 1.1, 1.2, 1.5, the four-point sound sources all have a strong sound leakage reduction capability (a low sound leakage index α). Wherein when d1/d2 is 1 or 1.1, the four-point sound source has a stronger sound leakage reduction capability than a single set of dipole sound sources (e.g., a first dipole sound source, a second dipole sound source). Therefore, in the practical open earphone, the ratio of the first dipole sound source spacing d1 to the second dipole sound source spacing d2 may be set within a certain range, so that the four-point sound source (two-group dipole sound source) may obtain a stronger sound leakage reduction capability than the one-group dipole sound source. Preferably, the ratio can range between 1 and 1.5.

Fig. 73C is a crossover flow chart of a narrowband speaker dipole sound source according to some embodiments of the present description. Fig. 73D is a crossover flow chart of a full band speaker dipole sound source according to some embodiments of the present description.

As shown in fig. 73C, two or more sets of narrowband speakers are provided to construct two or more dipole sound sources. By using a set of narrowband speaker units (single side 2*n, n.gtoreq.2), and a signal processing module. The frequency responses of the set of narrowband speaker units are complementary and collectively cover the audible frequency band. Taking the left side as an example: a1 to An form n dipole sound sources together with B1 to Bn, respectively, and the dipole sound source interval d can be set _n To regulate the near-field and far-field signal response of the dipole sound source in each frequency band. To enhance the near-field low frequency signal, the far-field high frequency signal is attenuated, typically such that the high frequency dipole sound source spacing is less than the low frequency dipole sound source spacing. The signal processing module comprises an EQ processing module and a DSP processing module, and realizes equalization and other common digital signal processing algorithms. The processed signal is connected with the corresponding acoustic transducer through a power amplifier to output the required acoustic signal.

As shown in fig. 74D, two or more sets of full-band speakers are provided to construct two or more dipole sound sources. By using a set of full-band speaker units (single side 2*n, n.gtoreq.2)And a signal processing module. The signal processing module comprises a set of filters to implement the molecular band operation. Taking the left side as an example: a1 to An form n dipole sound sources together with B1 to Bn, respectively, and the dipole sound source interval d can be set _n To regulate the near-field and far-field signal response of the dipole sound source in each frequency band. To enhance the near-field low frequency signal, the far-field high frequency signal is attenuated, typically such that the high frequency dipole sound source spacing is less than the low frequency dipole sound source spacing. The signal processing module also comprises an EQ processing module and a DSP processing module, and realizes equalization and other common digital signal processing algorithms, such as amplitude modulation, phase modulation, time delay and the like for signals. The processed signal is connected with the corresponding acoustic transducer through a power amplifier to output the required acoustic signal.

Fig. 74 illustrates a schematic diagram of a cell phone having a multiple hole structure according to some embodiments of the present disclosure. As shown, a top 7420 of the handset 7400 (i.e., an upper end surface "perpendicular" to the handset display) is provided with a plurality of holes. By way of example only, the hole portions 7401 may constitute one set of dipole sound sources for outputting low frequency sound, and the two hole portions 7402 may constitute another set of dipole sound sources for outputting high frequency sound. The spacing between the hole portions 7401 may be greater than the spacing between the hole portions 7402. A first speaker 7430 and a second speaker 7440 are provided inside the housing of the mobile phone 7400. The low-frequency sound generated by the first speaker 7430 may be transmitted outward through the hole portion 7401, and the high-frequency sound generated by the second speaker 7440 may be transmitted outward through the hole portion 7402. When the user places the hole portions 7401 and 7402 near the ear to listen to the voice information, the hole portions 7401 and 7402 can make a stronger near-field sound to the user, and at the same time, can reduce leakage to the surrounding environment. Moreover, the hole part is formed in the top of the mobile phone, but not in the upper part of the mobile phone display screen, so that the space required by the hole part arranged on the front surface of the mobile phone can be saved, the area of the mobile phone display screen can be further increased, and the appearance of the mobile phone can be more concise and attractive.

In some embodiments, the headset may further include a microphone for capturing ambient noise and converting the captured ambient noise into an electrical signal. In some embodiments, the controller may further include a noise reduction module for adjusting the sound source signal based on the electrical signal to cause the sound output by the first speaker or the second speaker to interfere with ambient noise, the interference reducing the ambient noise.

In all the above embodiments, the sound playing system formed by the speaker groups may be directional, so that the connection line between each pair of speakers is directed approximately toward the ears of the person, to achieve the effect that the sound volume heard by the wearer is large and the sound volume heard by surrounding persons is small. In some embodiments, since the listening effect of the open binaural headphones is susceptible to interference from ambient noise, a monitoring microphone for monitoring ambient noise may be added to the system, and the control system may dynamically adjust the sound signal processing system according to the characteristics of the noise. The control system can dynamically adjust parameters according to the monitoring result obtained by the monitoring microphone, so as to adjust the sound signal to obtain better listening effect. In some embodiments, since the open binaural earphone listening effect is susceptible to interference from ambient noise, microphones to monitor ambient noise may be added to the system and form an active noise reduction system with the control system for better listening.

Fig. 75 is a schematic diagram of an earphone according to some embodiments of the present description. As shown in fig. 75, the earphone 7500 may include a housing 7510 and a diaphragm 7520. The diaphragm 7520 may be disposed in a cavity formed by the housing 7510, and front and rear sides of the diaphragm 7520 are respectively provided with a front chamber 7530 and a rear chamber 7540 for radiating sound. The housing 7510 is provided with a first hole portion 7511 and a second hole portion 7512, the front chamber 7510 can be acoustically coupled with the first hole portion 7511, and the rear chamber 7510 can be acoustically coupled with the second hole portion 7512. When the diaphragm 7520 vibrates, sound waves of the front side of the diaphragm 7520 can be emitted from the first hole portion 7511 through the front chamber 7530, and sound waves of the rear side of the diaphragm 7520 can be emitted from the second hole portion 7512 through the rear chamber 7510, thereby forming a dipole sound source including the first hole portion 7511 and the second hole portion 7512. In some embodiments, as shown in fig. 75, when the user uses the headset 7500, the headset 7500 may be positioned near the pinna and the first aperture portion 7511 may be directed toward the user's ear canal opening 7511, thereby enabling sound emanating from the first aperture portion 7511 to propagate toward the user's ear canal opening. The second aperture portion 7512 may be distant from the ear canal opening 7501 relative to the first aperture portion 7511, a distance between the first aperture portion 7511 and the ear canal opening 7501 being smaller than a distance between the second aperture portion 7512 and the ear canal opening 7501.

In some embodiments, when the diaphragm 7520 vibrates, the front and rear sides of the diaphragm 7520 may respectively serve as an acoustic wave generating structure to generate acoustic waves with equal amplitude and opposite phases. In some embodiments, equal-amplitude, opposite-phase sound waves may radiate outward through the first and second aperture portions 7511 and 7512, respectively, forming a dipole sound source that may interfere with and cancel at a spatial point (e.g., far field), such that the problem of leakage from the far field of the earphone 7500 is effectively ameliorated.

Fig. 76A is a schematic diagram of sound pressure level sound field distribution of the headphones 7500 shown in fig. 75 at low frequencies. As shown in fig. 76A, in the middle-low frequency range (e.g., 50Hz-1 kHz), the sound field distribution of the earphone 7500 exhibits a good dipole sound leakage state. That is, in the middle-low frequency range, the dipole sound source constituted by the first hole portion 7511 and the second hole portion 7512 of the earphone 7500 outputs sound waves in opposite phases, and the two sound waves are mutually subtracted in the far field according to the principle of sound wave anti-phase cancellation, so that the effect of reducing far-field leakage is achieved.

In some embodiments, sound waves emitted from both sides of the diaphragm 7520 may first pass through the acoustic transmission structure and then radiate outward from the first aperture portion 7511 and/or the second aperture portion 7512. The acoustic transmission structure may refer to an acoustic path through which sound waves radiate from diaphragm 7520 to the external environment. In some embodiments, the acoustic transmission structure may include a housing 7510 between the diaphragm 7510 and the first aperture 7511 and/or the second aperture 7512.

In some embodiments, the acoustic transmission structure may include an acoustic cavity. The acoustic cavity may be an amplitude space reserved for the diaphragm 7520, for example, the acoustic cavity may include a cavity formed between the diaphragm 7520 and the housing 7510. For another example, the acoustic cavity may also include a cavity formed between the diaphragm 7520 and a magnetic circuit system (not shown). In some embodiments, the acoustic transmission structure may be in acoustic communication with the first aperture portion 7511 and/or the second aperture portion 751, which may also be part of the acoustic transmission structure. In some embodiments, when the diaphragm 7520 is far from the ear canal opening 7501, or when the radiation direction of the sound wave generated by the diaphragm 7520 is not directed toward or away from the ear canal opening 7501 as desired, the sound wave may be guided to a desired position through the sound guide tube, and then radiated to the external environment by the first hole portion 7511 and/or the second hole portion 7512, whereby the acoustic transmission structure may further include the sound guide tube. In some embodiments, the acoustic transmission structure may have a resonant frequency, and the acoustic transmission structure may resonate when the frequency of the sound wave generated by the diaphragm 7520 is near the resonant frequency. Under the influence of the acoustic transmission structure, the acoustic waves located in the acoustic transmission structure also resonate, which may change the frequency content of the transmitted acoustic waves (e.g. add additional resonance peaks to the transmitted acoustic waves) or change the phase of the transmitted acoustic waves in the acoustic transmission structure. The phase and/or amplitude of the sound wave radiated from the first hole portion 7511 and/or the second hole portion 7512 is changed compared to when resonance is not occurring, and the change in phase and/or amplitude may affect the effect of cancellation of interference of the sound wave radiated from the first hole portion 7511 and the second hole portion 7512 at a spatial point. For example, when resonance occurs, the phase difference of the sound waves radiated from the first hole portion 7511 and the second hole portion 7512 changes, and, illustratively, when the phase difference of the sound waves radiated from the first hole portion 7511 and the second hole portion 7512 is small (for example, less than 120 °, less than 90 °, or 0 or the like), the effect of interference cancellation of the sound waves at the space point is weakened, and it is difficult to play the effect of sound leakage reduction; alternatively, the sound waves having smaller phase differences may also overlap each other at a spatial point, increasing the amplitude of the sound wave at the spatial point (e.g., far field) near the resonance frequency, thereby increasing the far field leakage of the earphone 7500. For another example, the resonance may cause the amplitude of the transmitted sound wave to increase near the resonance frequency of the acoustic transmission structure (e.g., appear as a resonance peak near the resonance frequency), at which time the amplitude of the sound wave radiated from the first hole portion 7511 and the second hole portion 7512 differ greatly, and the effect of the interference cancellation of the sound wave at the space point is weakened, and it is difficult to achieve the effect of sound leakage reduction.

Fig. 76B is a schematic diagram of sound pressure level sound field distribution of the earphone 7500 shown in fig. 75 at resonance. As shown in fig. 76B, when an acoustic transmission structure of the headphones 7500 (for example, the case 7510 between the diaphragm 7520 and the second hole portion 7512) resonates, an acoustic signal radiated outward from the second hole portion 7512 plays a dominant role in the entire sound field distribution. That is, when the acoustic transmission structure resonates, the amplitude/phase of the sound wave actually radiated from the earphone 7500 (e.g., the second hole portion 7512) is different from the original amplitude/phase of the sound wave radiated from the diaphragm 7510, resulting in that the two sound waves radiated from the first hole portion 7511 and the second hole portion 7512 not only do not reduce leakage sound of the far field but also increase leakage sound of the far field. In some embodiments, the problem of increased leakage of the headphones 7500 in the far field can be ameliorated by adjusting the structure of the headphones 7500 to eliminate or reduce resonance of the acoustic transmission structure.

Fig. 77A is a schematic structural diagram of an earphone according to some embodiments of the present description. In some embodiments, as shown in fig. 77A, the earphone 7700 may include a housing 7710, a speaker 7720, and a filtering structure 7730.

Speakers 7720 may be used to convert electrical signals into sound signals (or sound waves). The housing 7710 may be used to carry a speaker 7720 and output sound waves through a first aperture 7711 and a second aperture 7712, respectively, in acoustic communication with the speaker 7720. For example, the housing 7710 may function as an acoustic transmission structure that transmits sound waves generated by the speaker 7720 to the first and second hole portions 7711 and 7712, respectively, and then radiates them outward. In some embodiments, the first aperture 7711 and/or the second aperture 7712 may also be part of an acoustic transmission structure that transmits sound waves generated by the speaker 7720 to a point in space outside the headset 7700. In some embodiments, the speaker 7720 may include a first sound wave generating structure and a second sound wave generating structure that generate a first sound wave and a second sound wave, respectively, that radiate out of the earphone 7700 through the first and second hole portions 7711 and 7712, respectively. In some embodiments, the first sound wave and the second sound wave may have a phase difference, and the first sound wave and the second sound wave having the phase difference may interfere at a spatial point, thereby reducing the amplitude of the sound wave received at the spatial point, and realizing the effect of dipole sound leakage reduction. In some embodiments, to ensure the effect of the first and second sound waves interfering at a point in space, thereby effectively reducing the amplitude of the sound waves received at that point in space, the phase difference between the first and second sound waves may be in the range 110 ° -250 °. In some embodiments, the phase difference between the first acoustic wave and the second acoustic wave may be in the range of 120 ° -240 °. In some embodiments, the phase difference between the first acoustic wave and the second acoustic wave may be in the range of 150 ° -210 °. In some embodiments, the phase difference between the first acoustic wave and the second acoustic wave may be in the range of 170 ° -190 °. In some embodiments, speaker 7720 may include a diaphragm (e.g., diaphragm 7520 shown in fig. 75) that, when vibrated, may output sound waves of opposite (or approximately opposite) phases, and of equal (or approximately equal) magnitudes, respectively, on opposite sides. At this time, the front and back surfaces of the diaphragm may be respectively used as the first sound wave generating structure and the second sound wave generating structure.

In some embodiments, as shown in fig. 77A, when the user wears the earphone 7700, the first hole 7711 and the second hole 7712 are located on both sides of the auricle, respectively. In some embodiments, the pinna may be equivalently a baffle that may increase the sound path of the second aperture portion 7712 to the ear canal opening 7703 such that the sound path of the second sound wave generating structure from the ear canal opening 7703 is greater than the sound path of the first sound wave generating structure from the ear canal opening 7703. 1-52 of the present disclosure, the baffle "blocks" between the second hole 7712 and the ear canal opening 7703, which is equivalent to increasing the sound path from the second hole 7712 to the ear canal opening 7703, and decreasing the amplitude of the sound wave radiated by the second hole 7712 at the ear canal opening 7703, so that the amplitude difference between the sound wave radiated by the second hole 7712 and the first hole 7711 is increased relative to the amplitude difference when the baffle is not provided, and thus the interference cancellation degree of the sound wave at the ear canal opening 7703 is reduced. At the same time, the baffle has little effect on the sound radiated by the second aperture 7712 in the far field, so that leakage to the surrounding environment can be reduced due to interference cancellation of the sound wave in the far field. In some embodiments, a first hole 7711 with a smaller sound path from the ear canal opening 7703 may be directed toward the ear canal opening 7703 for dominant listening functions, while a second hole 7712 with a larger sound path from the ear canal opening 7703 may be used for dominant leakage reduction functions. It should be appreciated that the headphones 7700 shown in fig. 77A are merely illustrative, and in some embodiments, the headphones 7700 may also be configured as described in other embodiments of the present disclosure to increase the sound path from the second aperture 7712 to the ear canal opening 7703. For example, as described in the embodiment of fig. 31-52, the first and second hole portions 7711, 7712 may also be located on the anterior side of the pinna, and a baffle may be provided between the first and second hole portions 7711, 7712. For another example, the first and second hole portions 7711 and 7712 may be located on the front side of the auricle, and a housing portion between the first and second hole portions 7711 and 7712 may be used as a baffle.

It should be appreciated that the sound path described herein refers to the distance traveled by the sound waves from the sound source location (e.g., the first and/or second hole portions 7711, 7712) to the ear canal orifice, rather than the straight line distance of the sound source location from the ear canal orifice. Fig. 77B is a schematic view of the sound path of the earphone 7700 shown in fig. 77A from the first hole 7711 and the second hole 7712 to the ear canal opening 7702. As shown in fig. 77B, if the first hole 7711 is provided on the front side of the auricle 7701 and the second hole 7712 is provided on the rear side of the auricle 7701, the first sound path 7704 from the first hole 7711 to the auricle 7703 may be a linear sound path distance from the first hole 7711 to the auricle 7703, and the second sound path 7705 from the second hole 7712 to the auricle 7703 may be a folding line sound path distance from the first hole 7711, bypassing the auricle 7701 and reaching the auricle 7703, wherein the second sound path 7705 may be larger than the first sound path 7704.

In some embodiments, the acoustic transmission structure of the headset 7700 may have a resonant frequency, about which the acoustic transmission structure may resonate when the frequency of the acoustic wave transmitted by the acoustic transmission structure is near the resonant frequency, as described in connection with fig. 75-76B and the description thereof. Under the influence of the acoustic transmission structure, the acoustic wave located in the acoustic transmission structure also resonates, which may change the frequency component of the transmitted acoustic wave (e.g., change the amplitude of the acoustic wave around the resonant frequency, such as adding an additional resonance peak to the transmitted acoustic wave), or change the phase of the acoustic wave transmitted in the acoustic transmission structure, thereby affecting the effect of the cancellation of the interference of the acoustic wave radiated from the first hole portion 7511 and the second hole portion 7512 at the spatial point. For example, with further reference to fig. 77A, the acoustic transmission structure of the headset 7700 can include a first acoustic transmission structure 7713 and a second acoustic transmission structure 7714. When the second acoustic transmission structure 7714 resonates, the phase of the second acoustic wave radiated through the second hole portion 7712 may change, interference cancellation may not be achieved by the first acoustic wave and the second acoustic wave at a spatial point (e.g., far field), and the amplitude of the acoustic wave near the resonance frequency at the spatial point may even be increased, thereby increasing leakage sound of the earphone 7700 at the far field. For another example, the resonance may cause the amplitude of the transmitted sound wave to increase near the resonance frequency of the acoustic transmission structure (e.g., appear as a resonance peak near the resonance frequency), at which time the amplitude of the sound wave radiated from the first hole 7711 and the second hole 7712 differ greatly, and the effect of the interference cancellation of the sound wave at the space point is weakened, which is difficult to achieve the effect of sound leakage reduction.

The filter structure 7730 may refer to a structure having a modulation effect on the frequency characteristics of the acoustic wave. For example, the filtering structure may have a modulating (e.g., absorbing, filtering, amplitude modulating, phase modulating, etc.) effect on sound waves of a particular frequency. In some embodiments, the filtering structure 7730 may include a sound absorbing structure that (or the filtering structure 7730) may be used to absorb sound waves of a target frequency range in the second sound wave, reducing the degree to which sound waves of the target frequency range in the first sound wave and the second sound wave interfere with each other at a spatial point, thereby reducing the amplitude of sound waves within the target frequency range at the spatial point. In some embodiments, the target frequency range may include a resonant frequency of the acoustic transmission structure, whereby the filtering structure 7730 may absorb sound waves near the resonant frequency to avoid a change in the phase and/or amplitude of the second sound wave caused by the acoustic transmission structure resonating near the resonant frequency, thereby reducing the amplitude of the sound wave near the resonant frequency at the point in space. The resonant frequency of the acoustic transmission structure is related to parameters of the acoustic transmission structure itself (e.g., the volume of the cavity formed by the acoustic transmission structure, the material, size, cross-sectional area, length of the sound guide tube, etc. of the acoustic transmission structure). In some embodiments, the resonant frequency may occur in the mid-high frequency band, e.g., 2 kHz-8 kHz. Accordingly, the target frequency range may include frequencies of the mid-high band. For example, the target frequency range may be in the range of 1kHz to 10 kHz.

In some embodiments, the first and second sound waves have shorter wavelengths in the higher frequency range, where the distance between the dipole sound sources formed by the first and second hole portions 7511, 7512 is not negligible compared to the wavelength. For example, the distance between the first hole portion 7511 and the second hole portion 7512 may be such that the sound paths of the first sound wave and the second sound wave from a spatial point (e.g., far field) are different, so that the phase difference between the first sound wave and the second sound wave at the spatial point is small (e.g., the same or close in phase), the first sound wave and the second sound wave cannot interfere and cancel at the spatial point, and may be superimposed at the spatial point, and the amplitude of the sound wave at the spatial point is increased. In some embodiments, the target frequency range may further include a frequency greater than the resonant frequency in order to reduce the amplitude of the sound waves by overlapping the first sound wave and the second sound wave in the higher frequency range. Thus, the filtering structure 7730 may absorb sound waves in a higher frequency range to reduce or avoid superposition of the first sound wave and the second sound wave at a spatial point, reducing the amplitude of the sound waves in the target frequency range at the spatial point. For example, the target frequency range may be in the range of 1kHz to 20 kHz.

In some embodiments, the spatial point may be a far-field spatial point, and the filtering structure 7730 may be configured to absorb the sound wave of the target frequency in the second sound wave, thereby reducing the amplitude of the sound wave of the target frequency range received by the far-field spatial point, and improving the leakage-reducing effect of the earphone 7700 in the far field. For example, as shown in fig. 77A, a filter structure 7730 may be provided in the second acoustic transmission structure 7714 between the speaker 7720 and the second hole portion 7712 so as to absorb the second acoustic wave transmitted by the second acoustic transmission structure 7714. It should be appreciated that the filtering structure 7730 shown in fig. 77A is merely illustrative, and not limiting to the actual use of the filtering structure 7730, and the filtering structure 7730 (e.g., the position of the filtering structure 7730, the sound absorption frequency, etc.) may be disposed so that the earphone 7700 has different sound effects in a spatial point. In some embodiments, the filtering structure 7730 may be disposed in the first acoustic transmission structure 7713 between the speaker 7720 and the first hole 7711, so as to absorb the sound wave in the target frequency range of the first sound wave transmitted by the first acoustic transmission structure 7713, and avoid the interference enhancement between the sound wave in the target frequency range and the sound wave in the same frequency range output by the second hole 7712 at the spatial point (for example, far field), so as to reduce the amplitude of the sound wave in the target frequency range received by the spatial point. In some embodiments, the filtering structure 7730 may also be disposed in both the first acoustic transmission structure 7713 and the second acoustic transmission structure 7714, so that sound waves in the target frequency range in the first sound wave and the second sound wave may be absorbed, and thus the amplitude of sound waves in the target frequency range at any point in space may be better reduced. In some embodiments, the filtering structure 7730 may also absorb low frequency sounds of a particular frequency range. For example, the filtering structure 7730 may be disposed in the acoustic transmission structure between the speaker 7720 and the second aperture 7712 to reduce the low frequency sound of a particular frequency range output from the second aperture 7712, avoid interference cancellation of the low frequency sound of the particular frequency range with the low frequency sound of the same frequency range output by the first aperture 7711 at a spatial point (e.g., near field), and thereby increase the volume of the earphone 7700 in the near field (i.e., delivered to the user's ear) within the particular frequency range. In some embodiments, the filtering structure 7730 may further include sub-filtering structures that absorb different frequency ranges, e.g., absorb middle and high frequency bands and low frequency bands, respectively, for absorbing sound in different frequency ranges.

According to the above-described embodiments, the filtering structure 7730 may absorb sound waves of the target frequency range in the first sound wave and/or the second sound wave, thereby reducing the amplitude of the sound waves in the target frequency range at the spatial point. And for first and second sound waves outside the target frequency range (e.g., sound waves less than the resonant frequency), the first and second sound waves may pass through the acoustic transmission structure to and interfere at the point in space, which may reduce the amplitude of sound waves outside the target frequency range at the point in space. That is, the first sound wave and the second sound wave outside the target frequency range (or referred to as the first frequency range) may interfere and cancel at the spatial point, and the effect of the dipole sound leakage reduction is achieved; the first sound wave and/or the second sound wave in the target frequency range (or referred to as the second frequency range) may be absorbed by the filtering structure 7730, so that an enhancement of the interference of the first sound wave and/or the second sound wave at the spatial point may be reduced or avoided, or an additional resonance peak generated by the first sound wave or the second sound wave under the action of the acoustic transmission structure may be weakened or absorbed, so that the amplitude of the sound wave in the target frequency range at the spatial point may be reduced. Thus, the embodiments of the present disclosure may enable the earphone 7700 to output the first sound wave and the second sound wave in the first frequency range by providing the filter structure 7730, and may enable the earphone 7700 (e.g., the second hole 7712) to reduce the sound wave output of the earphone 7700 near or above the resonance frequency of the acoustic transmission structure, thereby reducing or avoiding the increase of the sound wave amplitude in the second frequency range at the spatial point (e.g., far field) while guaranteeing the interference cancellation of the earphone 7700 in the first frequency range, so that the full-band sound leakage reduction effect may be ensured.

In some embodiments, the filtering structure 7730 may include a sound absorbing structure, which may include at least one of a resistive sound absorbing structure or a sound absorbing structure. For example, the function of the filtering structure 7730 may be implemented by a resistive sound absorbing structure. As another example, the function of the filtering structure 7730 may be implemented by a resistive sound absorbing structure. As another example, the function of the filtering structure 7730 may also be implemented by a resistive, hybrid sound absorbing structure.

The resistive sound absorbing structure may refer to a structure capable of providing acoustic resistance as sound waves pass. Acoustic resistance may refer to the resistance that an acoustic wave needs to overcome when passing through a resistive sound absorbing structure, which may reduce or consume the acoustic energy of the acoustic wave. For example, when sound waves pass through a resistive sound absorbing structure, the resistive sound absorbing structure may utilize friction created by movement of air within the structure to convert sound energy into heat energy such that the sound energy is consumed, thereby achieving a sound absorbing effect.

In some embodiments, the resistive sound absorbing structure may include at least one of a porous sound absorbing material or an acoustic gauze. The porous sound absorbing material or the acoustic gauze may include a plurality of voids, and when sound waves are transmitted in the porous sound absorbing material or the acoustic gauze, air carrying the sound waves moves among the plurality of voids and rubs with the porous sound absorbing material or the acoustic gauze, and the sound energy can be converted into heat energy to be consumed due to viscosity and heat conduction effect of the porous sound absorbing material or the acoustic gauze. In some embodiments, the voids may include through holes, bubbles, mesh, and the like. For example, the interior of the porous sound absorbing material may be provided with a plurality of through holes or air bubbles, which may communicate with each other and with the outside air of the resistive sound absorbing structure. For example, a plurality of mesh openings may be included in the acoustic screen. In some embodiments, the material of the resistive sound absorbing structure may include an inorganic fibrous material (e.g., glass wool, rock wool, etc.), an organic fibrous material (e.g., plant fibers such as cotton, hemp, etc., or lignocellulosic articles, etc.), a foam material, etc., or any combination thereof.

In some embodiments, the sound absorption coefficient of the porous sound absorbing material may be adjusted such that the porous sound absorbing material is capable of absorbing sound waves in the second frequency range of the first sound wave and/or the second sound wave. In some embodiments, the porous sound absorbing material may have a sound absorption coefficient greater than 0.3 in a second frequency range in order to enable the porous sound absorbing material to absorb sound waves in the second frequency range in the first sound wave and/or the second sound wave. In some embodiments, the acoustic screen has an acoustic resistance, which can be varied by adjusting the porosity of the acoustic screen to enable the acoustic screen to absorb sound waves in the second frequency range in the first sound wave and/or the second sound wave. In some embodiments, the acoustic screen may have an acoustic resistance in the range of 10Rayl-700 Rayl in order to enable the acoustic screen to absorb sound waves in the second frequency range of the first sound wave and/or the second sound wave.

In some embodiments, the resistive sound absorbing structure may be disposed anywhere on the first acoustic wave and/or second acoustic wave transmission path. For example, a porous sound absorbing material or an acoustic gauze may be attached to the inner wall of the acoustic transmission structure. For another example, the porous sound absorbing material or acoustic gauze may form at least a portion of an inner wall of the acoustic transmission structure. As another example, a porous sound absorbing material or an acoustic gauze may fill at least a portion of the interior of the acoustic transmission structure.

78A-78C are schematic illustrations of resistive sound absorption structures according to some embodiments of the present description.

In some embodiments, as shown in fig. 78A-78C, headphones 7800 can include a housing 7810 and a speaker 7820. The housing 7810 may be provided with a hole portion 7811 in acoustic communication with the speaker 7820, and sound waves generated by the speaker 7820 may be radiated to the outside of the earphone 7800 through the hole portion 7811. The housing 7810 and the hole 7811 may serve as an acoustic transmission structure of the earphone 7800 for transmitting sound waves generated by the speaker 7820 to a spatial point. The resistive sound absorbing structure 7830 (e.g., porous sound absorbing material or acoustic gauze) may form at least a portion of an inner wall of the acoustic transmission structure. For example, as shown in fig. 78A, the upper inner wall of the housing 7810 may be composed of a sound-blocking structure 7830 (e.g., a porous sound-absorbing material or an acoustic gauze). The sound waves emitted by the speaker 7820 may be absorbed by the resistive sound absorbing structure 7830 at a target frequency range as they pass through the acoustic transmitting structure. In some embodiments, the target frequency range may include a frequency greater than or equal to a resonance frequency of the acoustic transmission structure, so that the acoustic wave may be prevented from resonating under the action of the acoustic transmission structure, and the acoustic wave greater than or equal to the resonance frequency may be reduced or prevented from being output from the hole 7811. In some embodiments, the resistive sound absorbing structure 7830 may also be attached to one or more sides of the inner wall of the acoustic transmission structure. For example, the resistive sound absorbing structure 7830 may be attached to a surface of any one or more of the inner walls on the housing 7810.

In some embodiments, the resistive sound absorption structure 7830 may fill at least a portion of the interior of the acoustic transmission structure. For example, as shown in fig. 78B, the sound-blocking structure 7830 may be completely filled inside the case 7810. Sound waves within the target frequency range emitted by the speaker 7820 may be absorbed by the resistive sound absorption structure 7830. In some embodiments, the resistive sound absorbing structure 7830 may also not completely fill the interior of the housing 7810.

In some embodiments, the resistive sound absorbing structure 7830 may also be affixed adjacent to one or more apertures in the acoustic transmission structure. For example, as shown in fig. 78C, the sound-blocking structure 7830 may be attached to an inner wall of the housing 7810 where the hole 7811 is located, and the hole 7811 may be covered with the sound-blocking structure 7830. Sound waves within the target frequency range emitted by the speaker 7820 may be absorbed by the resistive sound absorption structure 7830. In some embodiments, the resistive sound absorbing structure 7830 may also be attached to the outer wall of the housing 7810 and cover the hole portion 7811.

The sound absorbing structure may refer to a structure that absorbs sound using resonance. In some embodiments, when the frequency of sound waves passing through the sound absorbing structure approaches the resonant frequency of the sound absorbing structure, air within the sound absorbing structure resonates to dissipate energy to achieve sound absorption. In some embodiments, the frequency of the absorbed sound waves of the sound resistive structure may be the same as or close to the resonant frequency. For example, the resonance frequency of the sound absorbing structure of the resistive type is 3kHz, and the sound absorbing structure of the resistive type absorbs sound waves of 3kHz or sound waves in a frequency range around 3 kHz. For example only, the nearby frequency range may include a frequency range corresponding to a magnitude of + -3 dB on the frequency response curve of the sound absorbing structure on both sides of the resonance peak at 3 kHz. Thus, the resonant frequency of the sound absorbing structure can be adjusted, so that the sound absorbing structure can absorb sound waves in a target frequency range. For example, the structure, material, etc. of the resistive sound absorbing structure may be tuned to achieve tuning of the resonant frequency.

In some embodiments, the sound absorbing structure may absorb sound waves of a single frequency, or may absorb sound of multiple frequencies, which may be within a target frequency range. For example, a single sound absorbing structure may be used to absorb sound waves at a single frequency. For another example, multiple sound absorbing resistant structures may be used to absorb sound waves at a single frequency. For another example, sound waves of a plurality of different frequencies may also be absorbed by a plurality of sound absorbing resistant structures. In some embodiments, the sound absorbing resistant structure may include, but is not limited to, perforated plates, microperforated plates, sheets, films, 1/4 wavelength resonance tubes, and the like, or any combination thereof. By way of example only, a number of exemplary sound absorbing resistant structures are provided below for detailing specific embodiments of the sound absorbing resistant structures.

In some embodiments, the sound absorbing resistant structure may comprise a perforated plate structure. The perforated plate structure may include one or more holes and one or more cavities, which may be in acoustic communication with the interior of the acoustic transmission structure through the one or more holes. The sound waves inside the acoustic transmission structure may enter the one or more cavities of the perforated plate structure through one or more holes and cause resonance of the perforated plate structure at a specific frequency, thereby enabling the perforated plate structure to achieve a sound absorbing effect. In some embodiments, the perforated plate structure may absorb sound waves having frequencies near its resonant frequency.

Fig. 79A-79D are schematic illustrations of perforated plate structures shown according to some embodiments of the present description. In some embodiments, as shown in fig. 79A-79D, the perforated plate structure 7940 may include one or more holes 7941 and one or more cavities 7942. In some embodiments, one or more apertures 7941 may be provided on an inner wall of an acoustic transmission structure (e.g., housing 7910) such that one or more cavities 7942 are in acoustic communication with an interior of the acoustic transmission structure (e.g., cavity 7912 of housing 7910) through the one or more apertures 7941. In some embodiments, the one or more cavities 7942 may include a helmholtz resonator. In some embodiments, the resonant frequency of perforated plate structure 7940 can include a frequency of a target frequency range, whereby when an acoustic wave of the target frequency range enters from cavity 7912 and cavity 7942, resonance of cavity 7942 can be induced, thereby achieving a sound absorbing effect.

In some embodiments, the resonant frequency of perforated plate structure 7940 may be related to parameters of perforated plate structure 7940, such as the volume of cavity 7942, the depth and open area of holes 7941, and the like. In some embodiments, the correspondence of the resonant frequency of the perforated plate structure 7940 to the parameters of the perforated plate structure 7940 can be as shown in equation (8) below.

Where c represents the sound velocity, S represents the opening area of the hole 7941, V represents the volume of the cavity 7942, t represents the depth of the hole 7941, and δ is the opening end correction amount of the hole 7941. In some embodiments, the resonant frequency of perforated plate structure 7940 may be adjusted by adjusting parameters such as the open area of holes 7941, the volume of cavity 7942, the depth of holes 7941, and the amount of correction of the open end of holes 7941, thereby adjusting the frequency of the sound waves absorbed by perforated plate structure 7940.

By way of example only, in some embodiments, the resonant frequency of perforated plate structure 7940 may be adjusted by adjusting the aperture of holes 7941 to control the open area of holes 7941. In some embodiments, to have the resonant frequency of perforated plate structure 7940 near the target frequency range so as to be able to absorb sound waves in the target frequency range, the aperture of holes 7941 may be in the range of 1mm-10mm, and correspondingly, the open area of holes 7941 may be in the range of 0.7mm ² -80 mm ² Within the range. In some embodiments, perforated plate structure 7940 may also include a micro-perforated plate structure. The micro-perforated plate structure may refer to a special perforated plate structure having a smaller aperture. In some embodiments, when perforated plate structure 7940 is a microperforated plate structure, the pore size of holes 7941 may be less than 1mm. In some embodiments, the aperture 7941 may have a pore diameter of less than 0.5mm.

In some embodiments, one or more of the cavities 7942 may be provided in a variety of arrangements. In some embodiments, as shown in fig. 79A, perforated plate structure 7940 may include a hole 7941 and a cavity 7942, the cavity 7942 may be in communication with cavity 7914 through the hole 7941. In some embodiments, as shown in fig. 79B, the perforated plate structure 7940 may include a plurality of holes 7941 and a plurality of cavities 7942, and the plurality of cavities 7942 may be disposed side by side along an extending direction of the acoustic transmission structure (X direction as shown in fig. 79B). In some embodiments, the resonant frequency of one or more of the cavities 7942 shown in fig. 79B may be the same or similar such that the perforated plate structure 7940 may absorb sound waves having frequencies in the vicinity of the resonant frequency. In some embodiments, when the plurality of cavities 7942 have the same or similar resonant frequency, the amount of sound absorption by the perforated plate structure 7940 may be related to the number of cavities 7942. For example, the greater the number of cavities 7942 of the same resonant frequency, the greater the amount of sound absorption by the perforated plate structure 7940; conversely, the fewer the number of cavities 7942 of the same resonant frequency, the less the amount of sound absorption of the perforated plate structure 7940. In some embodiments, the hole-penetrating rate of perforated plate structure 7940 may be increased, thereby increasing the sound absorption of perforated plate structure 7940. In some embodiments, the perforated plate structure of perforated plate structure 7940 (e.g., the perforated portion of housing 7910) may be referred to as a perforated plate, and the perforation ratio may refer to the ratio of the area of the plurality of holes 7941 in the perforated plate to the total area of the perforated plate. In some embodiments, the perforation rate is not too high in order to ensure stability of the perforated plate. In some embodiments, the corresponding porosity of perforated plate structure 7940 can be in the range of 5% -80%. In some embodiments, the resonance frequencies of at least two cavities 7942 of the one or more cavities 7942 may be different. For example, a portion of the one or more cavities 7942 may have a resonant frequency equal to a resonant frequency of the acoustically transmissive structure and a portion of the cavities 7942 may have a resonant frequency greater than the resonant frequency of the acoustically transmissive structure. In some embodiments, by providing cavities with different resonant frequencies in the plurality of cavities 7942, the perforated plate structure 7940 may be made to absorb sound waves at multiple frequencies or ranges of frequencies, thereby increasing the sound absorption bandwidth of the perforated plate structure 7940.

In some embodiments, when a plurality of cavities 7942 are disposed side by side along the direction of extension of the acoustic transmission structure, at least two cavities 7942 of the one or more cavities 7942 may be disposed independently or may be in communication with each other. For example, as shown in fig. 79B, two adjacent cavities 7942 of the plurality of cavities 7942 may be spaced apart from each other by a cavity sidewall (shown in phantom in fig. 79B). For another example, two adjacent cavities 7942 of the plurality of cavities 7942 may not include a cavity sidewall, such that the two adjacent cavities 7942 may communicate with each other.

In some embodiments, as shown in fig. 79C, the perforated plate structure 7940 may include a plurality of cavities 7942, the plurality of cavities 7942 in acoustic communication with the interior of the acoustic transmission structure (e.g., the housing 7910) through one aperture 7941. In some embodiments, multiple cavities 7942 may be arranged in series. For example, as shown in FIG. 79C, one cavity 7942 may be in acoustic communication with one bottom wall 7942-1 or side wall of another cavity 7942 through its corresponding aperture. In some embodiments, the plurality of cavities 7942 arranged in series may also have the same or different resonant frequencies. In some embodiments, when a plurality of cavities 7942 arranged in series have the same or similar resonant frequency, the amount of sound absorption of the perforated plate structure 7940 may be related to the number of cavities 7942. For example, the greater the number of cavities 7942 of the same resonant frequency disposed in series, the greater the amount of sound absorption by the perforated plate structure 7940. In some embodiments, when the plurality of cavities 7942 disposed in series have different resonant frequencies, the perforated plate structure 7940 may be caused to absorb sound waves of multiple frequencies or ranges of frequencies, which may increase the sound absorption bandwidth of the perforated plate structure 7940.

In some embodiments, multiple cavities 7942 may also be arranged in series and side-by-side fashion at the same time. For example, a portion of the plurality of cavities 7942 may be disposed in series and a portion of the cavities 7942 may be disposed side-by-side.

In some embodiments, perforated plate structure 7940 may also include a micro-perforated plate structure. The micro-perforated plate structure may refer to a special perforated plate structure having a smaller aperture. For example, the microperforated panel structure may comprise one or more relatively small-pore micropores and one or more cavities that may be in acoustic communication with the interior of the acoustically transmissive structure via one or more of the cavities. For example only, as shown in fig. 79D, the microperforated panel structure 7950 may comprise a plurality of micropores 7951 and cavities 7952, which cavities 7952 may be considered as a plurality of interconnected cavities. In some embodiments, microperforated panel structure 7950 may be suitable for acoustic transmission structures with smaller cavities than the perforated panel structures described above.

In the embodiment of the present disclosure, when the sound waves enter the cavity 7952 through the micro holes 7951, the sound waves passing through the micro holes 7951 may be increased due to the small aperture of the micro holes 7951, so that the sound absorption effect of the micro perforated plate structure 7950 may be improved. In some embodiments, the pore size of the micropores 7951 may be less than 1mm. In some embodiments, the porosity of the microperforated panel structure 4950 may be increased, thereby increasing the sound absorption of the microperforated panel structure 4950. In some embodiments, the perforation rate is not too high in order to ensure stability of the perforated plate. In some embodiments, the microperforated panel structure 7950 may have a corresponding perforation rate in the range of 1% -5%.

In some embodiments, the resonant frequency of microperforated panel structure 7950 may be related to parameters of the microperforated panel structure, such as cavity depth, relative acoustic mass, etc. In some embodiments, the correspondence between the resonant frequency of the microperforated panel structure and the parameters of the microperforated panel structure can be expressed as shown in equation (9) below:

where c represents the speed of sound, m represents the relative sound mass, and D represents the cavity depth (i.e., the distance of the microperforated panel from the cavity bottom wall 7952-1). In some embodiments, the resonant frequency of the micro-perforated plate structure 7950 may be adjusted by adjusting parameters such as the cavity depth or relative acoustic mass of the micro-perforated plate structure, thereby adjusting the frequency of the acoustic waves absorbed by the micro-perforated plate structure 7950.

In some embodiments, when the microperforated panel structure 7950 includes a plurality of cavities 7952, the plurality of cavities 7952 may have the same or different resonant frequencies. In some embodiments, at least two of the plurality of cavities 7952 may be disposed side-by-side, may be disposed in series, or may be disposed in series and side-by-side simultaneously with the plurality of cavities 7952. The cavities 7952 in the microperforated panel structure 7950 may be arranged in a manner similar to the perforated panel structure 7940 described above and will not be described again here.

In some embodiments, the sound absorbing resistive structure may comprise a 1/4 wavelength resonant tube structure. The 1/4 wavelength resonance tube structure may refer to an absorption assembly using the 1/4 wavelength resonance principle. In some embodiments, the 1/4 wavelength resonant tube structure may include a lumen and sound waves entering the 1/4 wavelength resonant tube structure may be superimposed upon themselves after being reflected within the lumen. For example, when the 1/4 wavelength resonance tube structure resonates by the sound wave entering the 1/4 wavelength resonance tube structure, a phase difference can be formed between the incident sound wave and the reflected sound wave, so that the sound wave and the reflected sound wave can cancel each other, and the sound absorption effect can be realized.

FIG. 79E is a schematic illustration of a 1/4 wavelength resonance tube structure according to some embodiments of the present disclosure. In some embodiments, as shown in fig. 79E, the 1/4 wavelength resonance tube structure 7960 may include one or more holes 7961 (or referred to as tube length openings) and one or more 1/4 wavelength resonance tubes 7962, and the one or more 1/4 wavelength resonance tubes 7962 may be in acoustic communication with the interior of the acoustic transmission structure through the one or more holes 7961. In some embodiments, the 1/4 wavelength resonance tube 7962 can be a tubular container and the 1/4 wavelength resonance tube 7962 can have a tube length of 1/4 of the wavelength of the resonance sound wave. The resonant acoustic wave may direct an acoustic wave that resonates the 1/4 wavelength resonator tube 7962. In some embodiments, the 1/4 wavelength resonator tube 7962 can be folded and rolled to save space when its tube length is longer. For example, as shown in fig. 79E, the 1/4 wavelength resonance tube 7962 can be folded and rolled multiple times to form a labyrinth structure, wherein the actual equivalent tube length of the 1/4 wavelength resonance tube 7962 can be the total length of the tube folded and rolled multiple times.

In some embodiments, the resonant frequency of the 1/4 wavelength resonator 7962 can be related to a parameter of the 1/4 wavelength resonator 7962, such as the tube length of the 1/4 wavelength resonator 7962, the tube length open end correction, and the like. In some embodiments, the correspondence between the resonance frequency of the 1/4 wavelength resonator 7962 and the parameters of the 1/4 wavelength resonator 7962 can be shown in the following formula (10):

Where c represents the sound velocity, L represents the tube length of the 1/4 wavelength resonance tube 7962, and δ is the tube length opening end correction amount of the 1/4 wavelength resonance tube 7962. In some embodiments, the frequency of the sound waves absorbed by the 1/4 wavelength resonance tube structure 7960 may be adjusted by adjusting parameters such as the tube length of the 1/4 wavelength resonance tube 7962, the tube length open end correction, and the like, to adjust the resonance frequency of the 1/4 wavelength resonance tube 7962.

In some embodiments, the resonance frequency of one or more 1/4 wavelength resonance tubes 7962 can be the same. Correspondingly, the 1/4 wavelength resonance tube structure 7960 may absorb sound waves having frequencies around the resonance frequency. In some embodiments, the amount of sound absorption of the 1/4 wavelength resonator tube structure 7960 may be related to the number of 1/4 wavelength resonator tubes 7962 at the same resonant frequency. For example, the greater the number of 1/4 wavelength resonator tubes 7962 of the same resonance frequency, the greater the amount of sound absorption of the 1/4 wavelength resonator tube structure 7960 around that resonance frequency.

In some embodiments, the resonance frequencies of at least two of the one or more 1/4 wavelength resonance tubes 7962 can be different. In some embodiments, the frequency range in which the resonant frequencies of the plurality of 1/4 wavelength resonance tubes 7962 are located may be related to the sound absorption bandwidth of the 1/4 wavelength resonance tube structure 7960. For example, the larger the frequency range in which the resonance frequencies of the plurality of 1/4 wavelength resonance tubes 7962 are located, the larger the sound absorption bandwidth of the 1/4 wavelength resonance tube structure 7960.

In some embodiments, one or more 1/4 wavelength resonator tubes 7962 can be provided in a variety of arrangements. In some embodiments, the 1/4 wavelength resonance tube structure 7960 may be disposed outside of an acoustic transmission structure (e.g., the housing 7910), and at least two 1/4 wavelength resonance tubes 7962 of the one or more 1/4 wavelength resonance tubes 7962 may be disposed side-by-side along an extension direction of the acoustic transmission structure.

In some embodiments, a 1/4 wavelength resonance tube structure 7960 may be disposed inside the acoustic transmission structure and around the aperture 7911. For example, a plurality of 1/4 wavelength resonance tubes 7962 may be attached to an inner wall of the housing 7910 where the hole 7911 is located and disposed around the hole 7911 of the housing 7910, wherein corresponding holes 7961 of the plurality of 1/4 wavelength resonance tubes 7962 may be disposed around an edge of the hole 7911. For more description of the placement of the 1/4 wavelength resonator tube around the aperture 7911, reference may be made to other portions of this specification, such as FIGS. 85A-85B and descriptions thereof.

In some embodiments, the sound absorbing structure may include a resistive sound absorbing structure and a sound absorbing structure. That is, the resistive sound absorbing structure and the resistive sound absorbing structure may be provided at the same time as the resistive hybrid sound absorbing structure, realizing the function of the filtering structure 7730. For example, the resistive hybrid sound absorbing structure may include a perforated plate structure and a porous sound absorbing material or an acoustic screen, wherein the porous sound absorbing material or acoustic screen may be disposed within a cavity of the perforated plate structure or may be disposed inside an acoustic transmission structure. For another example, the impedance hybrid sound absorbing structure may include a 1/4 wavelength resonant tube structure and a porous sound absorbing material or an acoustic screen, wherein the 1/4 wavelength resonant tube structure may be disposed inside or outside the acoustic transmission structure and the porous sound absorbing material or the acoustic screen may be disposed inside the acoustic transmission structure. As another example, the resistive hybrid sound absorbing structure may include a perforated plate structure, a 1/4 wavelength resonant tube structure, a porous sound absorbing material, or an acoustic gauze.

By way of example only, an exemplary resistive hybrid sound absorbing structure is provided below, detailing a specific implementation of the resistive hybrid sound absorbing structure. Fig. 80 is a schematic illustration of an impedance hybrid sound absorbing structure according to some embodiments of the present description.

In some embodiments, as shown in fig. 80, an acoustically transmissive structure (e.g., housing 8010) of a headset 8000 may include a perforated plate structure 8040 and a resistive sound absorbing structure 8030 therein. The resistive sound absorbing structure 8030 can include a porous sound absorbing material and/or an acoustic screen. In some embodiments, as shown in fig. 80, the resistive sound absorbing structure 8031 may be disposed about the opening of one or more apertures 8041 of the perforated plate structure 8040. In some embodiments, by providing the resistive hybrid sound absorbing structure as shown in fig. 80, not only can resonance sound absorption by the resistive sound absorbing structure be achieved, but also friction dissipation of sound waves can be increased by the resistive sound absorbing structure, thereby increasing the sound absorption bandwidth and further improving the sound leakage reduction effect within the target frequency range of the earphone 8000.

It should be appreciated that the resistive hybrid sound absorbing structure shown in fig. 80 is for illustrative purposes only and is not limiting of the present description. In some embodiments, the resistive sound absorbing structure 8031 may be affixed to the inner wall of the cavity 8042 of the perforated plate structure 8040. In some embodiments, the resistive sound absorbing structure 8031 can fill at least a portion of the cavity 8042. In some embodiments, as shown in fig. 78A-78C, the resistive sound absorbing structure 8031 may also be disposed within the housing 8010 or as part of the housing 8010.

Three exemplary headphones are provided below, respectively, detailing the specific implementation of the filtering structure. Fig. 81 is a schematic diagram of an earphone provided with a filtering structure according to some embodiments of the present description.

As shown in fig. 81, the earphone 8100 may include a housing 8110 and a speaker 8120. The first hole portion 8111 and the case 8110 between the speaker 8120 may function as a first acoustic transmission structure, and the second hole portion 8112 and the case 8110 between the diaphragm 8120 may function as a second acoustic transmission structure. In some embodiments, first bore portion 8111 may be directed toward the ear canal opening of the user, and the sound path from second bore portion 8112 to the ear canal opening may be greater than the sound path from first bore portion 8111 to the ear canal opening. Compared to the existing earphone 7500, the earphone 8100 provided in the embodiments of the present disclosure can provide the micro-perforated plate structure 8140 in the second acoustic transmission structure. For example, a microperforated panel 8143 may be disposed in the cavity 8114 in the second acoustic transmission structure, the microperforated panel 8143 may be disposed parallel to the diaphragm and connected at both ends to the sidewalls of the second acoustic transmission structure, respectively. The microperforated panel 8143 may cooperate with the housing 8110 to form the cavities 8142 of the microperforated panel structure 8140.

In some embodiments, the parameters of the micro-perforated plate structure 8140 can be set such that the resonant frequency of the micro-perforated plate structure 8140 is near the resonant frequency of the second acoustic transmission structure. By way of example only, the apertures of the micro holes 8141 are in the range of 0.3mm-0.5mm, the penetration rate is in the range of 0.5% -3%, the arrangement pitch of the micro holes 8141 may be in the range of 2.5mm-4.5mm, the depth of the micro holes 8141 is in the range of 0.5mm-1mm, and the depth of the cavities 8142 is about 1mm. The arrangement pitch may refer to a distance between the same positions (e.g., circle centers) on the adjacent two micro holes 8141. Correspondingly, the resonant frequency of the microperforated panel structure 8140 may be distributed over the frequency range of 2700Hz to 8800 Hz.

Fig. 82A is a frequency response graph of the earphone 8100 shown in fig. 81 at the first hole portion 8111 when there is a filter structure. Fig. 82B is a frequency response graph of the earphone 8100 shown in fig. 81 at the second hole portion 8112 when there is a filter structure. As shown in fig. 82A, a curve 8210 shows a frequency response curve of the earphone 8100 at the first hole portion 8111 when the microperforated panel structure 8140 is not provided in the second acoustic transmission structure, and a curve 8220 shows a frequency response curve of the earphone 8100 at the first hole portion 8111 when the microperforated panel structure 8140 is provided in the second acoustic transmission structure. As shown in fig. 82B, a curve 8230 shows a frequency response curve of the earphone 8100 at the second hole portion 8112 when the microperforated panel structure 8140 is not provided in the second acoustic transmission structure, and a curve 8240 shows a frequency response curve of the earphone 8100 at the second hole portion 8112 when the microperforated panel structure 8140 is provided in the second acoustic transmission structure. In some embodiments, the frequency response curves measured at the first hole portion 8111 and the second hole portion 8112 may represent the frequency response curves of the first acoustic transmission structure and the second acoustic transmission structure, respectively.

As shown in fig. 82A and 82B, when the microperforated panel structure 8140 is not provided in the second acoustic transmission structure, the curve 8230 has a resonance peak 8231 near 4kHz, i.e., the second acoustic transmission structure resonates near 4 kHz. According to the embodiment of the present disclosure, when the second acoustic transmission structure resonates, the phase and/or amplitude of the transmitted acoustic wave changes, and at this time, the acoustic wave radiated from the second hole portion 8112, which dominates the leakage reduction, may not interfere with the acoustic wave radiated from the first hole portion 8111 at a spatial point (e.g., far field) to cancel, thereby making it difficult to realize the leakage reduction function. In addition, when the acoustic wave transmitted in the second acoustic transmission structure is equal to or greater than 4kHz, the acoustic wave radiated by the second hole portion 8112 may also increase the leakage sound at the spatial point, and therefore, it is necessary to eliminate or reduce the acoustic wave output of equal to or greater than 4kHz at the second hole portion 8112.

Further in combination with the curve 8230, when the microperforated panel structure 8140 is disposed in the second acoustic transmission structure, the resonant peak 8231 of the curve 8230 around 4kHz becomes a valley 8241 on the curve 8240. Thus, the microperforated panel structure 8140 can effectively reduce sound waves output at the second hole portion 8112 at frequencies near the resonance frequency of the second acoustic transmission structure. Further, as can be seen from the combination of the curves 8210 and 8220, when the microperforated panel structure 8140 is provided in the second acoustic transmission structure, the frequency response curve of the sound wave radiated from the first hole portion 8111 slightly changes, and the resonance frequency of the first acoustic transmission structure slightly decreases, but the change amplitude is not large. That is, when the microperforated panel structure 8140 is provided in the second acoustic transmission structure, the amplitude of the sound wave around 4kHz radiated from the first hole portion 8111 is slightly changed, the sound wave transmitted from the first hole portion 8111 to the ear canal orifice is not substantially affected, and the amplitude of the sound wave around 4kHz radiated from the second hole portion 8112 is reduced, so that the amplitude of the sound wave around 4kHz received at a spatial point (for example, far field) can be reduced, and thus the leakage sound at the spatial point can be reduced.

According to fig. 82A and 82B and the description thereof, a filter structure may be provided at the second acoustic transmission structure, and the amplitude of the acoustic wave received at the spatial point (e.g., far field) in the vicinity of the resonance frequency of the second acoustic transmission structure may be reduced while not substantially affecting the volume of the sound of the ear canal opening. In some embodiments, the resonant frequency of the ear canal may be in the range of 3kHz to 4 kHz. That is, the user's human ear is more sensitive to sounds around 3-4 kHz. Therefore, through setting the sound absorption frequency of the filtering structure in the second acoustic transmission structure, the far-field sound leakage in the range of 3 kHz-4 kHz can be reduced, so that the sound leakage heard by other users is obviously reduced, and the earphone 8100 has a better far-field sound leakage reducing effect.

It should be appreciated that the headphones 8100 illustrated in fig. 81, 82A, and 82B are merely exemplary, and are not limiting to the use scenario of the filtering structure. In some embodiments, the filtering structure may be disposed in the first acoustic transmission structure so as to absorb sound waves of a target frequency range among sound waves transmitted by the first acoustic transmission structure, thereby reducing the amplitude of sound waves of the target frequency range received by a near-field spatial point (e.g., an ear canal orifice). In some embodiments, the filtering structure may be further disposed in the first acoustic transmission structure and the second acoustic transmission structure at the same time, so that the sound waves in the target frequency range in the sound waves transmitted by the first acoustic transmission structure and the second acoustic transmission structure may be absorbed at the same time, so as to reduce the amplitude of the sound waves in the target frequency range at any spatial point. In some embodiments, frequencies greater than 4kHz may also be included in the sound absorption frequency of the filtering structure so that higher frequency sound waves may be absorbed.

Fig. 83 is a schematic diagram of an earphone provided with a filtering structure according to some embodiments of the present description.

As shown in fig. 83, the headphones 8300 shown in fig. 83 may be provided with an impedance hybrid sound absorbing structure on the second acoustic transmission structure, as compared to the existing headphones 7500. The resistive hybrid sound absorbing structure may include a micro-perforated plate structure 8340 and a resistive sound absorbing structure 8330. Compared to the earphone 8100 described above, the earphone 8300 provided in the embodiments of the present disclosure may add the resistive acoustic structures 8330 at the micropores of the microperforated panel structure 8340.

In some embodiments, the resistive sound absorbing structure 8330 may be an acoustic gauze. In some embodiments, the acoustic screen may have an acoustic resistance of 260Rayl. The arrangement of the microperforated panel structure 8340 is similar to that of the microperforated panel structure 8140 described in fig. 81 and will not be described again. For more description of the resistive sound absorbing structure 8330, reference may be made to other parts of this specification, such as fig. 78A-78B and descriptions thereof, described above.

In some embodiments, microperforated panel structure 8340 may absorb sound waves within a target frequency range of sound waves emitted by speaker 8320; in addition, the sound wave emitted by the speaker 8320 can be absorbed by the sound-absorbing structure 833, so that the amplitude of the sound wave in the target frequency range received at the space point can be further reduced, and the sound leakage reducing effect of the earphone 8300 can be further improved.

Fig. 84A is a frequency response graph of the earphone 8300 shown in fig. 83 at the first hole portion 8311 when the filter structure is present or absent, and fig. 84B is a frequency response graph of the earphone 8300 shown in fig. 83 at the second hole portion 8312 when the filter structure is present or absent. As shown in fig. 84A, a curve 8410 represents a frequency response curve of the headphones 8300 at the first hole portion 8311 when the impedance hybrid sound absorbing structure is not provided in the second acoustic transmission structure, and a curve 8420 represents a frequency response curve of the headphones 8300 at the first hole portion 8311 when the impedance hybrid sound absorbing structure is provided in the second acoustic transmission structure. As shown in fig. 84B, a curve 8430 represents a frequency response curve of the earphone 8300 at the second hole portion 8312 when the impedance hybrid sound absorbing structure is not provided in the second acoustic transmission structure, and a curve 8440 represents a frequency response curve of the earphone 8300 at the second hole portion 8312 when the impedance hybrid sound absorbing structure is provided in the second acoustic transmission structure.

As shown in fig. 84A and 84B, when the impedance hybrid sound absorbing structure is not provided in the second acoustic transmitting structure, the curve 8430 has a resonance peak 8431 in the vicinity of 4kHz, i.e., the second acoustic transmitting structure resonates in the vicinity of 4 kHz. Further in combination with the curve 8440, when an impedance hybrid sound absorbing structure is provided in the second sound transmitting structure, the resonance peak 8431 of the curve 8430 in the vicinity of 4kHz becomes the valley 8441 on the curve 8440. Thus, the impedance hybrid sound absorbing structure can effectively reduce sound waves output at the second hole portion 8312 at frequencies around the resonance frequency of the second acoustic transmission structure. Further, as is known from the graphs 8410 and 8420, when the impedance-mixed sound absorbing structure is provided in the second acoustic transmission structure, the amplitude of the sound wave around 4kHz radiated from the first hole portion 8311 slightly changes, and the amplitude of the sound wave around 4kHz radiated from the second hole portion 8312 decreases, so that the amplitude of the sound wave around 4kHz received at a spatial point (for example, far field) can be reduced, and thus leakage sound at the spatial point can be reduced. In addition, comparing the curve 8240 and the curve 8440, it is seen that the valley 8441 has a lower amplitude than the valley 8241, and that the curve 8440 has a lower amplitude over a wider frequency range (e.g., 2kHz-4 kHz). Therefore, compared with the earphone 8100 with the micro-perforated plate structure 8340, the earphone 8300 with the impedance mixing type sound absorption structure has larger sound absorption quantity near 4kHz and larger sound absorption frequency range, thereby further improving the sound leakage reduction effect of the earphone 8300.

Fig. 85A is a schematic diagram of an earphone provided with a 1/4 wavelength resonance tube structure according to some embodiments of the present description. Fig. 85B is a schematic perspective view of a 1/4 wavelength resonance tube structure according to some embodiments of the present disclosure.

As shown in fig. 85A, the earphone 8500 may be provided with a 1/4 wavelength resonance tube structure 8550 in the second acoustic transmission structure, as compared to the existing earphone 7500. The 1/4 wavelength resonance tube structure 8550 is attached to an inner wall of the second hole portion 8512 of the housing 8510, and a plurality of 1/4 wavelength resonance tubes 8552 and a plurality of holes 8551 may be disposed around an opening of the second hole portion 8512. Since the second hole 8512 and the second acoustic transmission structure are not independent of each other and have no clear limitation, the 1/4 wavelength resonance tube structure 8550 may be considered to be provided in the second acoustic transmission structure or may be considered to be provided in the second hole 8512. In some embodiments, the 1/4 wavelength resonance tube structure 8550 may absorb sound waves in a target frequency range in the second sound wave emitted by the speaker 8520, thereby reducing the amplitude of the sound wave in the target frequency range received at the spatial point and improving the sound leakage reduction effect of the earphone 8500.

In some embodiments, parameters of the 1/4 wavelength resonance tube structure 8550 may be set such that the resonance frequency of the 1/4 wavelength resonance tube structure 8550 is within the target frequency range. For example, the 1/4 wavelength resonance tube 8552 may have a tube length in the range of 10mm to 22mm and a resonance frequency in the range of 4kHz to 9 kHz.

Fig. 86A is a frequency response graph of the earphone 8500 shown in fig. 85A at the first aperture portion 8511 with or without the filter structure. Fig. 86B is a frequency response graph of the earphone 8500 shown in fig. 85A at the second aperture portion 8512 with or without the filter structure. As shown in fig. 86A, a curve 8610 shows a frequency response curve of the earphone 8500 at the first hole portion 8511 when the 1/4 wavelength resonance tube structure 8550 is not provided in the second acoustic transmission structure, and a curve 8620 shows a frequency response curve of the earphone 8500 at the first hole portion 8511 when the 1/4 wavelength resonance tube structure 8550 is provided in the second acoustic transmission structure. As shown in fig. 86B, a curve 8630 shows a frequency response curve of the earphone 8500 at the second hole 8512 when the 1/4 wavelength resonance tube structure 8550 is not provided in the second acoustic transmission structure, and a curve 8640 shows a frequency response curve of the earphone 8500 at the second hole 8512 when the 1/4 wavelength resonance tube structure 8550 is not provided in the second acoustic transmission structure.

As shown in fig. 86A and 86B, in combination with curves 8610 and 8620, the provision of the 1/4 wavelength resonance tube structure 8550 in the second acoustic transmission structure causes a slight change in the amplitude around a certain frequency of the acoustic wave output from the first hole portion 8511 (for example, an increase in the amplitude around frequencies such as 5kHz and 10 kHz). Further combining the curves 8530 and 8540, when the 1/4 wavelength resonance tube structure 8550 can thus make the amplitude of the sound wave output by the second hole portion 8512 significantly lower in the high frequency band (for example, in the range of the frequency higher than 6 kHz) with little influence on the sound wave output by the first hole portion 8511, the earphone 8500 can be made to have a better sound leakage reduction effect.

Possible benefits of embodiments of the present description include, but are not limited to: (1) By arranging the baffle between the two hole parts of the earphone, the volume of the near-field listening position can be obviously improved under the condition that the far-field listening volume is not obviously increased; (2) The output effect of the open earphone is improved by setting the baffle and/or two hole parameters (the ratio of the height of the baffle to the distance between the two holes, the sound Cheng Bi from the vibrating diaphragm to the two holes, etc.); (3) The low-frequency dipole sound source and the middle-high frequency dipole sound source are respectively constructed to output near-field sound and far-field leakage-reducing sound, so that the open earphone has higher near-field volume output in a low frequency band, the problems of excessively low cut-off frequency of the high-frequency leakage-reducing sound, excessively narrow leakage-reducing sound band and the like are solved, and the output effect of the open earphone is further improved; (4) By arranging the filter structure to absorb the sound wave in the target frequency range, the amplitude of the sound wave in the target frequency range of the open earphone at the space point can be reduced, the influence of resonance of the acoustic transmission structure on far-field leakage is reduced or eliminated, and the sound leakage reducing effect of the open earphone is improved.

While the basic concepts have been described above, it will be apparent to those skilled in the art that the foregoing detailed disclosure is by way of example only and is not intended to be limiting. Although not explicitly described herein, various modifications, improvements, and adaptations to the present disclosure may occur to one skilled in the art. Such modifications, improvements, and modifications are intended to be suggested within this specification, and therefore, such modifications, improvements, and modifications are intended to be included within the spirit and scope of the exemplary embodiments of the present invention.

Claims

1. An earphone, comprising:

a first sound wave generating structure and a second sound wave generating structure, which generate a first sound wave and a second sound wave, respectively, the first sound wave and the second sound wave having a phase difference in the range of 120 ° -240 °;

an acoustic transmission structure for transmitting the first acoustic wave and the second acoustic wave to a spatial point outside the earphone, wherein the first acoustic wave and the second acoustic wave transmitted to the spatial point interfere in a first frequency range, the interference reducing the amplitude of the first acoustic wave in the first frequency range; and

and the filtering structure is used for reducing the amplitude of the sound wave in the second frequency range at the spatial point.

2. The earphone of claim 1, wherein the filtering structure comprises a sound absorbing structure for absorbing sound waves in the second frequency range in the first sound wave and/or the second sound wave.

3. The earphone of claim 2, wherein the first frequency range is less than the second frequency range, the second frequency range comprising a resonant frequency value of the acoustic transmission structure.

4. The earphone of claim 2 wherein the sound absorbing structure is configured to absorb sound waves of a second frequency range of the second sound wave to reduce the amplitude of sound waves of the second frequency range received at the sound receiving point, wherein the sound path of the second sound wave generating structure from the human ear canal orifice is greater than the sound path of the first sound wave generating structure from the human ear canal orifice.

5. The earphone of claim 2, wherein the acoustic transmission structure comprises at least a housing and one or more apertures disposed on the housing, the sound absorbing structure comprising at least one of a resistive sound absorbing structure or a sound absorbing structure.

6. The earphone of claim 5, wherein the sound-blocking structure comprises at least one of a porous sound-absorbing material or an acoustic gauze.

7. The earphone of claim 6, wherein the porous sound absorbing material or acoustic gauze is attached to or forms at least a portion of an inner wall of the acoustic transmission structure.

8. The earphone of claim 6, wherein the earphone comprises a pair of earphone arms,

the porous sound absorbing material or acoustic gauze fills at least a portion of the interior of the acoustic transmission structure, or

The porous sound absorbing material or acoustic gauze is attached near the one or more hole portions.

9. The earphone of claim 5, wherein the sound absorbing structure comprises a perforated plate structure comprising one or more holes and one or more cavities in acoustic communication with the interior of the acoustic transmission structure through the one or more holes.

10. The earphone of claim 9, wherein the resonance frequencies of the plurality of cavities are different.

11. The earphone of claim 9, wherein at least two of the one or more cavities are disposed side-by-side along a direction of extension of the acoustic path.

12. The earphone of claim 11, wherein adjacent ones of the at least two cavities are spaced apart from or in communication with each other by a cavity sidewall.

13. The earphone of claim 9, wherein at least two of the one or more cavities are disposed in series.

14. The earphone of claim 9, wherein at least one of the one or more cavities further comprises a sound blocking structure therein, the sound blocking structure comprising at least one of a porous sound absorbing material or an acoustic gauze.

15. The earphone of claim 14, wherein the resistive sound absorption structure is disposed at an opening of the one or more apertures.

16. The earphone of claim 9, wherein the aperture of the hole is in the range of 1mm-10 mm.

17. The earphone of claim 9, wherein the perforation rate of the perforation plate structure is in the range of 5% -80%.

18. The earphone of claim 9, the aperture of the hole being less than 1mm.

19. The earphone of claim 9, wherein the perforation ratio of the perforated plate structure is between 1% and 5%.

20. The headphones of claim 5, wherein the sound absorption resistant structure comprises a 1/4 wavelength resonant tube structure, the 1/4 wavelength resonant tube structure comprising one or more apertures and one or more 1/4 wavelength resonant tubes, the one or more 1/4 wavelength resonant tubes in acoustic communication with the interior of the acoustic transmission structure through the one or more apertures.

21. The earphone of claim 20, wherein the earphone comprises a pair of earphone arms,

the resonance frequencies of at least two of the one or more 1/4 wavelength resonance tubes are different.

22. The headphones of claim 20, wherein the 1/4 wavelength resonance tube structure is disposed outside the acoustic transmission structure, and wherein at least two 1/4 wavelength resonance tubes of the one or more 1/4 wavelength resonance tubes are disposed side-by-side along the direction of extension of the acoustic transmission structure.

23. The headphones of claim 20, wherein the 1/4 wavelength resonance tube structure is disposed inside the acoustic transmission structure, wherein the one or more 1/4 wavelength resonance tubes are disposed around the second aperture portion.

24. An earphone, comprising:

a first sound wave generating structure;

the acoustic transmission structure is used for transmitting the first sound wave generated by the first sound wave generation structure to a space point outside the earphone, wherein the first sound wave generates resonance with resonance frequency under the action of the acoustic transmission structure; and

and the filtering structure is used for absorbing the sound wave in a target frequency range of the first sound wave transmitted by the acoustic transmission structure so as to reduce the amplitude of the sound wave received at the space point, wherein the target frequency range comprises the resonant frequency.

25. An earphone, comprising:

a speaker;

a housing for carrying the speaker and having a first hole portion and a second hole portion in acoustic communication with the speaker, respectively, the speaker outputting sound waves having a phase difference through the first hole portion and the second hole portion; and

and the filter structure is arranged in the acoustic transmission structure between the first hole part or the second hole part and the loudspeaker and is used for absorbing sound waves in a target frequency range, wherein the target frequency range is in a range of 1 kHz-10 kHz.

26. The earphone of claim 25, wherein the first aperture to human ear canal orifice is less acoustic than the second aperture to human ear canal orifice, the filtering structure being disposed in an acoustic transmission structure between the second aperture and the speaker.

27. The earphone of claim 26, wherein the first and second aperture portions are each located on a same side of the pinna of the user, and wherein a baffle is disposed between the first and second aperture portions that increases the sound path from the second aperture portion to the ear canal opening of the person.

28. The headset of claim 25, further comprising:

a second speaker, wherein the housing is configured to carry the second speaker and has a third hole portion and a fourth hole portion that are respectively in acoustic communication with the second speaker, and the second speaker outputs sound waves having a phase difference through the third hole portion and the fourth hole portion; and

and a controller for causing the speaker to output sound waves in a first frequency range from the first and second hole portions, and causing the second speaker to output sound waves in a second frequency range from the third and fourth hole portions, the first frequency range including a higher frequency than the second frequency range.

29. The earphone of claim 28, wherein the first aperture portion and the second aperture portion have a first spacing therebetween, the third aperture portion and the fourth aperture portion have a second spacing therebetween, and the first spacing is less than the second spacing.

30. The earphone of claim 28, wherein the controller comprises:

the electronic frequency division module is used for dividing the frequency of the sound source signal to generate a high-frequency signal corresponding to a first frequency range and a low-frequency signal corresponding to a second frequency range, wherein the high-frequency signal drives the loudspeaker to generate sound waves, and the low-frequency signal drives the second loudspeaker to generate sound waves.