CN114466290A - Acoustic device and audio system - Google Patents
Acoustic device and audio system Download PDFInfo
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- CN114466290A CN114466290A CN202210158943.1A CN202210158943A CN114466290A CN 114466290 A CN114466290 A CN 114466290A CN 202210158943 A CN202210158943 A CN 202210158943A CN 114466290 A CN114466290 A CN 114466290A
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
- H04R9/00—Transducers of moving-coil, moving-strip, or moving-wire type
- H04R9/02—Details
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
- H04R9/00—Transducers of moving-coil, moving-strip, or moving-wire type
- H04R9/06—Loudspeakers
Abstract
The present application relates to the field of acoustics, in particular to an acoustic device and an audio system, the acoustic device comprising: a speaker driver and a waveguide structure; a waveguide structure disposed around the speaker driver, the waveguide structure having: a first frequency response corresponding to sound emitted from the speaker driver traveling directly to the listening position such that a head-related transfer function is added to the sound emitted from the speaker driver traveling directly to the listening position, the head-related transfer function providing height cues for the sound traveling directly from the speaker driver position to the listening position to simulate sound from above the listening environment; and a second frequency response corresponding to sound emitted from the speaker driver that is required to travel in reflection to the listening position, a ratio of the first frequency response and the second frequency response being equal to the head-related transfer function.
Description
The application is a divisional application proposed by the Chinese application with the application date of 2020, 12 and 14, the application number of 202011465798.9 and the name of 'an acoustic device and an audio system'.
Technical Field
The present application relates to the field of acoustics, and in particular, to an acoustic device and an audio system.
Background
The sound emitted from nature received by human ears comes from multiple directions, but if the sound is recorded and reproduced, the direction of the sound cannot be perceived by comparing the sound reproduced by the speakers with the original sound source, and if the sound with a specific direction, such as the sound from above, is to be reproduced, the sound needs to be reproduced by additional speakers above the listener.
Therefore, how to reproduce sounds in other directions without increasing the number of speakers or changing the positions of the speakers is a difficult problem to be solved.
Disclosure of Invention
One of the embodiments of the present application provides an acoustic device, which includes: a speaker driver and a waveguide structure; the waveguide structure is disposed around the speaker driver, and a surface of the waveguide structure forms a plurality of curved structures arranged radially along the speaker driver, the speaker driver being configured to play at least one of surround sound audio or immersive audio; the waveguide structure has: a first frequency response corresponding to sound emitted from the speaker driver traveling directly to a listening position such that a head-related transfer function is added to the sound emitted from the speaker driver traveling directly to the listening position, the head-related transfer function providing high cues for sound traveling directly from the speaker driver position to the listening position simulating sound from above a listening environment; and a second frequency response corresponding to sound emitted from the speaker driver that is required to travel in reflection to a listening position such that the sound emitted from the speaker driver that is required to travel in reflection to a listening position does not have height cue information, wherein a ratio of the first frequency response and the second frequency response is equal to the head-related transfer function.
In some embodiments, the first frequency response is a first off-axis response at a first angle from the speaker driver axis and the second frequency response is a second off-axis response at a second angle from the speaker driver axis.
In some embodiments, the second off-axis response is a smooth curve in the frequency domain.
In some embodiments, the first frequency response is a first off-axis response at a first angle from the speaker driver axis, and the second frequency response is an average response over a plurality of angles from the speaker driver axis.
In some embodiments, the second frequency response corresponds to a power response of the acoustic device.
In some embodiments, the power response of the acoustic device is a smooth curve over the frequency domain.
In some embodiments, the speaker driver is a tweeter driver.
In some embodiments, the speaker driver includes a driver cone and a cone dust cap, and the waveguide is sleeved outside the driver cone and the cone dust cap.
In some embodiments, each curve of the waveguide structure surface is symmetrically distributed with respect to the axis of the speaker driver.
One of the embodiments of the present application provides an audio system, which includes the acoustic device as described above; the audio system is used to process mixing, rendering, and playback of source audio information in the audio system, including one or more computers or processing devices executing software instructions.
Drawings
The present application will be further explained by way of exemplary embodiments, which will be described in detail by way of the accompanying drawings. These embodiments are not intended to be limiting, and in these embodiments like numerals are used to indicate like structures, wherein:
fig. 1 is a schematic view of an application scenario of an acoustic device according to some embodiments of the present application.
FIG. 2 is a schematic diagram of an acoustic device according to some embodiments of the present application.
Fig. 3 is a cross-sectional structural schematic of a waveguide structure according to some embodiments of the present application.
Fig. 4 is a frequency response diagram of an acoustic device according to some embodiments of the present application.
FIG. 5 is a schematic diagram of an application scenario of an acoustic device according to some embodiments of the present application;
fig. 6 is a schematic view of an application scenario of an acoustic device according to other embodiments of the present application.
Detailed Description
In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings used in the description of the embodiments will be briefly introduced below. It is obvious that the drawings in the following description are only examples or embodiments of the application, from which the application can also be applied to other similar scenarios without inventive effort for a person skilled in the art. Unless otherwise apparent from the context, or otherwise indicated, like reference numbers in the figures refer to the same structure or operation.
One or more embodiments described herein may be implemented in an audio or audio-visual system that processes source audio information in a mixing, rendering, and playback system that includes one or more computer or processing devices executing software instructions.
Fig. 1 is a schematic view of an application scenario of an acoustic device according to some embodiments of the present application.
As shown in fig. 1, in some embodiments, an application scenario 100 of an acoustic device includes an acoustic device 110, a listener 120, and a listening environment.
The acoustic device 110 is a transducing device that converts audio information (e.g., an electrical signal containing the audio information) into sound. The acoustic device 110 can obtain the audio information in different ways, for example, reading stored data on a specific medium (e.g., a hard disk, a CD), or obtaining network data containing the audio information through a network, etc. An exemplary acoustic device 110 may include a horn. In some embodiments, the acoustic device 110 may include one or more speakers, such as a combination of 2 speakers built in stereo, 2.1 sounds built in home theater (3 speakers), 5.1 sounds (6 speakers), 7.1 sounds (8 speakers), or 7.1.4(12 speakers), etc. In some embodiments, the sound waves emitted by the acoustic device 110 may also be viewed as being superimposed by one or more speakers.
The quality and effect of the sound heard by the listener 120 depends to some extent on the structure of the acoustic device 110, the listening environment, and the location of the acoustic device 110 in the listening environment. For convenience of description only, the following describes a case where the position of the listener 120 within the listening environment does not change during the period from the sound emission from the acoustic device 110 to the listening of the listener 120. It is to be appreciated that by utilizing the acoustic device 110 and its coupling to the listening environment as described herein, enhanced immersive listening effects can be achieved for listeners located in different locations.
The listening environment may refer to any open, partially enclosed, or fully enclosed area, such as a room that may be used for playback of audio content alone or with video or other content, and may be embodied in a home, theater, studio, or the like. The room has at least one boundary, which may be a ceiling, a floor, or a wall, and further, the wall may be located at different positions of the listener 120, such as four sides of the front, the rear, the left side, and the right side. The boundaries of the room described herein are to be understood as having a certain reflection and absorption of sound, which changes the frequency distribution of the sound.
In some embodiments, the application scenario 100 may further include a digital-to-analog converter (DAC), a power Amplifier (Amplifier), and the like, which are required to drive the acoustic device 110, and are not limited in this specification.
In some embodiments, the acoustic device 100 can be used to play different types of audio, such as at least one of surround sound audio or immersive audio. Surround sound audio enables modeling of audio in front and back spatial orientations of the listener 120 via multiple channels or a specific algorithm; immersive audio enables the reproduction of audio at the spatial height (above or below) of the listener 120 through multiple channels or a particular algorithm. In some embodiments, in order to provide a realistic height and surround experience for the listener 120, a head-related transfer function implementation may be introduced in the production of sound by the acoustic device 100.
The Head-Related Transfer Function (HRTF), also referred to as binaural Transfer Function, may describe the Transfer of sound waves from a sound source to both ears. The acoustic wave comprehensive filtering device can simulate the result of comprehensive filtering of acoustic waves by human physiological structures (such as a head, an auricle, a trunk and the like). For example, in practical applications, the acoustic device 110 may be used to play HRTF processed signals (which may also be described as adding HRTFs to the source audio signals), or the structure of the acoustic device 110 may be used to adjust the generated sounds so that the finally played sounds include HRTF effects, so as to simulate various spatial hearing effects, and thus simulate the effect of the sound source emitting sounds at different positions.
In some embodiments, the HRTFs may be expressed as
Where theta is the angle in the vertical direction (elevation angle),
is the angle in the horizontal direction and ω is the angular frequency of the sound wave. The elevation angle θ may reflect the position of the sound source in the vertical direction relative to the listener 120, and different elevation angles θ may correspond to different height cues in the vertical direction; horizontal angle
The position of the sound source in the horizontal direction with respect to the listener 120 can be reflected.
In some embodiments, not only source audio information, but also a head related function may be further added to the sound that provides the listener 120 with an immersive listening effect to alter the position of the sound source as perceived by the listener 120. For illustrative purposes only, the sound content contained in the source audio information may be represented as x (ω), the sound heard by the listener 120 at the listening position is represented as y (ω), and ideally, the sound heard by the listener 120 may be represented as:
in the process of converting a source audio signal into sound and further transmitting the sound to a listener through a listening environment, a certain head related transfer function should be added to the original sound content. For example, in order to provide a particular head-related transfer function in the sound heard by the listener 120, in some embodiments, active addition of head-related transfer functions in the electronic domain may be employed. Specifically, by adding a head-related transfer function to the digital signal of the source audio (e.g., adding a head-related transfer function to the source audio or adding a head-related transfer function effector during the original audio source decoding process), the sound generated by the acoustic device 110 can have the effect of the head-related transfer function.
For example only, as shown in fig. 1, in order to provide a high-level cue signal to a sound, a head-related transfer function may be added to the original audio information x (ω) in the electronic domain, and then the acoustic device converts the signal with the head-related transfer function into the sound for transmission.
As shown in fig. 1, the axis of the acoustic device 110 is at an angle of 70 ° to the horizontal, and the sound at an off-axis angle of 25 ° (represented by sound wave 114) is heard by the listener 120 after a reflection from the upper boundary (ceiling) of the listening environment, and the sound at an off-axis angle of 70 ° (represented by sound wave 112) is directly heard by the listener 120 without reflection. The effect of the listening environment making one reflection of the sound may be equivalent to adding another head-related transfer function to the sound. For the sake of brevity, the head-related transfer function added in the electronic domain and the head-related transfer function added based on the upper boundary reflection may both be represented as
Which represents height cues containing an elevation angle of 45 deg.. Further, consider the off-axis response at 25 ° off-axis on the acoustic device 110 (the off-axis response as referred to herein is understood to mean acousticThe learning device and its structure have a certain adjustment effect on the sound emitted outward at an angle off the axis, the adjustment can change the frequency distribution in the sound) can be expressed as H25(ω) the off-axis response at 70 off-axis can be represented as H70(ω), the sound heard by the listener 120 in this embodiment can be expressed as:
for convenience of description, H in the formula (2)25(ω) can be viewed approximately as the flat axis response, H, of the acoustic device 11025(ω) may be approximately 1, but since the acoustic device 110 playing surround sound audio or immersive audio is not an omnidirectional loudspeaker, H25(omega) and H70There will be a significant difference in (ω), so H needs to be considered and retained70(ω), where equation (2) can be written as:
since the distance that the sound wave 114 travels to the listener 120 is greater than the distance that the sound wave 112 travels without reflection to reach the listener 120, the sound wave 114 lags behind the sound wave 112 from reaching the listener 120. The sound component corresponding to the sound wave 112, i.e. the equation above contains H, considering that the brain of the listener 120 will interpret the first arrival sound of a sound source as giving the direction of the sound source70The (ω) part, which, because it is not reflected, will reach the listener 120 first, which will determine the sound direction perceived by the listener 120. But due to their large off-axis angle, the off-axis response of the acoustic device 110 on the sound waves 112 is not negligible and can affect the effect of the head-related transfer function. Moreover, the sound component corresponding to the sound wave 114 (sound undergoing primary reflection) in equation (3), i.e., the second term on the right of the equal sign in equation (3), is significantly different from the sound wave 112 due to the presence of the squaring operation of the head-related transfer function, so that it is difficult for the listener 120 to feel uniform sound effects. HealdIn the above, this scheme causes deterioration of the head related transfer function, so that the high cue information is not obvious in the reproduced sound, and the fidelity of the sound is not high.
In addition to adding head-related transfer functions in the electronic domain as described above, some embodiments of the present application may add head-related transfer functions in the acoustic domain such that sounds passing through different acoustic paths to a listener have the same or similar head-related transfer functions, thereby enabling the listener to experience a uniform sound effect. Unlike the above-described manner of adding a head-related transfer function in the electronic domain, the manner of adding a head-related transfer function in the acoustic domain as described herein can be implemented by designing the structure of the acoustic device. Briefly, by designing the structure of the acoustic output device, it is possible to have an off-axis response of the acoustic output device that deviates from different axis angles (e.g., an off-axis response at 70 ° off-axis, an off-axis response at 25 ° off-axis, etc.) with an equivalent or similar head-related transfer function effect.
FIG. 2 is a schematic diagram of an acoustic device according to some embodiments of the present application.
Referring to fig. 2, the acoustic device 210 includes a speaker driver 211 and a waveguide structure 213. In some embodiments, the acoustic device 210 may be suitable for use in the application scenario 100 shown in fig. 1 as the acoustic device 110 in fig. 1.
It should be noted that the speaker driver 211 is an electroacoustic transducer that generates sound in response to an electrical audio input signal, and that the speaker driver 211 may be implemented by any suitable type, geometry, and size, and may include horns, cones, ribbon transducers, and the like.
In some embodiments, the acoustic device 210 may also include a structure to hold the speaker driver 211, which may be referred to as a cabinet or housing. In some embodiments, a plurality of speaker drivers 211 may also be provided on the cabinet.
In some embodiments, the speaker driver 211 may be a cone speaker, which is characterized by a simple structure and high energy conversion efficiency. The classification of cone speakers includes band-based classification (high pitch, middle pitch, low pitch, etc.) and material-based classification (e.g., pulp, bulletproof fiber, polymer rayon, etc.), and the structures of the respective types may be the same or different.
The speaker driver 211 may include a driver cone and a cone dust cap. The driver cone can convert an electric signal into mechanical motion under the driving of the magnet and the voice coil, and the driver cone drives air to move so as to make sound. In order to prevent dust, impurities and the like from entering the loudspeaker driver 211, a cone dustproof cover is further arranged at the center of the cone of the driver, and optionally, in some embodiments, the cone dustproof cover is further provided with a conical outer contour in a direction away from the cone of the driver, so that a certain phase correction function is provided.
In some embodiments, the speaker driver 211 may have other structures according to its form, such as a band-shaped diaphragm included in a band-shaped speaker, in addition to the cone and cone dust cover of the driver and the magnet and voice coil for driving, which are not limited herein.
The waveguide structure 213 may extend in one or more directions and may be a structure that modulates acoustic waves propagating thereon or therein. In some embodiments, a waveguide structure 213 is disposed around the speaker driver 211. For example, the waveguide structure may be sleeved outside the driver cone and the cone dust cap.
As shown in fig. 2, the surface of the waveguide structure 213 forms a plurality of curved structures 215 arranged along the radial direction of the speaker driver 211. The plurality of curved structures 215 undulate along the axial direction of the speaker driver 211, and a wave-shaped structure is formed on the peripheral side of the speaker driver 211, which has an effect that sound waves generated from the speaker driver 211 have different influences on sounds of different frequencies according to their different undulations when passing through the curved structures 215. In particular, the distance of each of these curvilinear structures 215 from the axis of the speaker driver 211 determines the frequency at which they affect sound. Each of the curved structures referred to herein may be understood as a structure in which the surface of the waveguide structure 213 is formed to be convex (a peak-like shape extending outward in the speaker driver axial direction) or concave (a valley-like shape extending inward in the speaker driver axial direction). The amplitude of the bumps or dips on the curvilinear structure 215 and their distance from the speaker driver 211 can affect the frequency distribution of the sound generated by the speaker driver 211 that radiates outward along a particular angle.
In this embodiment, each curve of the surface of the waveguide structure 213 is symmetrically distributed with respect to the axis of the speaker driver 211, and the cross section of the waveguide structure 213 taken along any radial direction is the same.
Fig. 3 is a cross-sectional structural schematic of a waveguide structure according to some embodiments of the present application.
Fig. 4 is a frequency response diagram of an acoustic device according to some embodiments of the present application.
Fig. 3 is a schematic cross-sectional view of the waveguide structure 213 in the radial direction. As shown in fig. 3, the areas of the surface of the waveguide structure 213 near the speaker driver (i.e., the areas of the waveguide structure near the center) are formed with raised and lowered projections or depressions, and the areas away from the speaker driver gradually become flat. The following description takes the concave depression 215a and the convex depression 215b on the curved structure 215 as examples. It should be noted that the curve formed by the recess 215a or the projection 215b around in the circumferential direction of the speaker driver may be understood as a curved structure on the curved structure 215. For illustrative purposes only, the dip 215a is located in a range of 1.2cm to 1.5cm from the inner boundary of the waveguide structure 213 in a radial direction (i.e., the x-direction in the figure) along the speaker driver 211. The vertical distance between the highest and lowest points on depression 215a (i.e., the distance in the y-direction in the figure) is approximately 4 cm. The protrusion 215b is located within a range of 2.7cm to 3.5cm from the inner boundary of the waveguide structure 213 in a radial direction along the speaker driver 211. The shape of the projection 215b is similar to a circular arc curve having a radius of about 4.3cm, and the vertical distance between the highest point and the lowest point on the projection 215b is about 5 cm. It will be appreciated that the frequency distribution of sound radiating outwardly at different angles can be adjusted to achieve a desired effect by the curved structure 215 formed by the similar depressions 215a and/or protrusions 215b on the waveguide structure 213.
Fig. 4 shows the effect of the waveguide structure 213 on the sound generated by the speaker driver 211. The frequency response of the sound emitted by the speaker driver 211 may be represented as 410 (which is assumed to be a horizontal line in the frequency domain for simplicity), while the off-axis response of the waveguide structure 213 to an angle off the axis of the speaker driver may be represented as 420. It should be appreciated that the relative position between the two response lines in fig. 4 is for illustrative purposes only and does not represent the relative magnitude of the frequency response of the sound emitted by the speaker driver 211 and the off-axis response of the waveguide structure 213 in an actual scenario, in order to facilitate the display of the frequency distribution of each response line. It can be seen that the waveguide structure has a negligible small change in the frequency response of the sound emitted by the speaker driver 211 in the frequency range below 1kHz, while the waveguide structure has a large influence on the frequency response of the sound emitted by the speaker driver 211 in the frequency range above 2 kHz. It will be appreciated that depending on the different curved shapes of the waveguide structure 213 and its different distance from the loudspeaker driver axis, different off-angle sounds emitted by the loudspeaker driver will have different frequency response curves after adjustment of the waveguide structure 213. This process may also be understood as the waveguide structure 213 may impose different frequency responses for different directions of sound emitted by the speaker driver.
In some embodiments, the curved structure of the surface of the waveguide structure 213 may also be distributed asymmetrically with respect to the axis of the speaker driver 211 in order to satisfy other conditions for imposing a different frequency response on the sound produced by the speaker driver. By way of example only, the waveguide structure on the side of the speaker driver 211 near the ceiling and the waveguide structure surface in the direction of the speaker driver 211 near the two walls may be curved in different numbers and/or forms to provide different variations in sound in different directions of diffusion, depending on the actual scene.
In some embodiments, the waveguide structure 213 may have other forms, such as a circular ring shape and having a curved cross-section, or a horn-shaped profile of the waveguide structure 213.
As described above, the waveguide structure 213 may impose different frequency responses for different directions of sound emitted by the speaker driver. In some embodiments, the frequency response imparted by the waveguide structure 213 for a sound of a certain direction may be related to the head-related transfer function. For example, the waveguide structure 213 in fig. 3 may be such that a head-related transfer function is added to sound emitted by the speaker driver 211 traveling directly to the listening position, the head-related transfer function providing a high cue for sound traveling directly from the speaker driver 211 position to the listening position, thereby simulating sound from the upper surface of the listening environment. In this process, the height cue information is added to the sound generated by the speaker driver by the adjustment of the waveguide structure 213 to the sound and/or the reflection of the sound by the listening environment boundary, so that the acoustic device can still make the sound from above the listening environment felt by the listener 120 when not required to be mounted on the upper surface of the listening environment. Hereinafter, a specific explanation will be made using different listening environments as examples.
In some other embodiments, to add a specific sound effect to the sound heard by the listener 120, the head-related transfer function may also be added in the acoustic domain and in the electronic domain of the speaker driver 211 simultaneously using the shape of the waveguide structure 213.
In some embodiments, the speaker driver 211 may be a tweeter driver. Since the head-related transfer function has a significant effect above 2kHz, only the effect of the head-related transfer function can be added to the high-frequency signal by the waveguide structure 213. In particular, the tweeter driver described herein may be used to reproduce high frequency signals in the frequency range of greater than 1kHz, greater than 1.5kHz, or greater than 2 kHz. Exemplary tweeter drivers may be dome speakers or aluminum strip speakers, etc.
In some embodiments, since the sound localization mechanism of the human ear is related to sound frequencies, e.g., phase difference localization for low frequency signals, intensity difference localization for medium frequency signals, and time difference localization for high frequency signals, adjustments can be made for different speaker drivers 211 and waveguide structures 213 to increase surround sound audio surround perception or immersive audio sound effects, depending on the actual usage scenario.
Fig. 5 is a schematic view of an application scenario of an acoustic device according to some embodiments of the present application.
The application scenario 200 shown in fig. 5 includes a listener 120 and an acoustic device 210. In some embodiments, the acoustic device 210 may be fixed, placed, or mounted in front of or behind the listener 120 by a cabinet or other support structure.
For ease of illustration, at least one ceiling included in the application scenario 200. In some other embodiments, one or more of the floor, two side walls, the acoustic device 210, and the wall behind the listener 120 may also be included in the application scenario 200. It is understood that when a ceiling is present in the application scenario 200, the sound generated by the acoustic device 210 that can be heard by the listener 120 travels directly to the listening position without being reflected, and travels to the listening position after being reflected by the ceiling.
The waveguide structure of the acoustic device 210 may have: a first frequency response corresponding to sound emitted from the speaker driver 211 traveling directly to the listening position, i.e. a first frequency response corresponding to sound waves 212. Since the sound waves 212 are offset from the speaker driver 211 axis at a first angle, the first frequency response may also be referred to as a first off-axis response. The first frequency response may be related to a head-related transfer function. In this case, it will be appreciated that the waveguide structure of the acoustic device 210 conditions the sound waves 212 emitted by the acoustic device 210 to impart a first frequency response to the sound traveling directly to the listening position with an effect equivalent to adding a head-related transfer function to the sound traveling directly to the listening position. The head-related transfer function may provide a high level of cues for sound traveling directly to the listening position (i.e., sound waves 212) to simulate sound from above the listening environment.
Further optionally, the waveguide structure of the acoustic device 210 may further have: a second frequency response corresponding to the sound emitted from the speaker driver 211 that needs to travel in reflection to the listening position, i.e. a second frequency response corresponding to the sound waves 214. The second frequency response may also be referred to as a second off-axis response due to the sound waves 214 being offset from the speaker driver 211 axis at a second angle. In some embodiments, a ratio of the first frequency response and the second frequency response is equal to the head-related transfer function.
For illustration purposes, the acoustic device 210 may be disposed at an inclination, as in the application scenario 200 shown in fig. 5. The axis of speaker driver 211 is at 70 ° to the horizontal, with sound at an off-axis angle of 25 ° (i.e., sound waves 214 off-axis at a second off-axis angle of 25 °) being heard by listener 120 after a single reflection from the ceiling, and sound at an off-axis angle of 70 ° (i.e., sound waves 212 off-axis at a first off-axis angle of 70 °) being heard directly by listener 120 without reflection. The effect of the listening environment making one reflection of the sound may be equivalent to adding another head-related transfer function to the sound.
For the sake of brevity, the head-related transfer function containing height cue information at an elevation angle of 45 ° continues to be taken as an example. The difference from the scenario in fig. 1 is that in fig. 5 no head-related transfer function is added to the source audio information x (ω) in the electronic domain. Similar to the scenario of FIG. 1, the second off-axis response of the acoustic device 210 may be represented as H25(ω), the first off-axis response may be represented as H70(ω) as mentioned before, the ratio of the first frequency response and the second frequency response is equal to the head-related transfer function, i.e.:
the sound heard by the listener 120 at the listening position includes direct arriving sound and reflected sound, represented as:
wherein x (ω). H70(ω) represents the direct-arriving sound heard by the listener 120 at the listening position,
representing reflected sound heard by the listener 120 at the listening position.
In some embodiments, the second off-axis response H is less due to the smaller off-axis angle25(ω) can be approximated as a smooth curve in the frequency domain, i.e. H25(ω) can be approximated as the flat axis response of the speaker, in which case H25Where (ω) is 1, equation (5) can be simplified as:
likewise, equation (4) can be converted to:
substituting equation (7) into equation (6) above, the sound heard by the listener 120 at the listening position can be obtained as:
as can be seen from equation (8), the sound heard by the listener 120 at the listening position is the original audio information with the head related transfer function added. Further, as mentioned above, the brain of listener 120 may interpret the first arrival sound of a sound source as giving the direction of the sound source. In the present embodiment, the sound that preferentially reaches the listening position of the listener 120 (i.e., the sound corresponding to the first off-axis response) contains the head-related transfer function with the height cue information at an elevation angle of 45 °, that is, the listener 120 can feel the spatial sound effect from above the listening space through the acoustic device disposed in front of it. Moreover, since the sounds heard in succession by the listener 120 (i.e., the sound waves 212 and the sound waves 214) have the same expression (the same head related transfer function), the listener 120 can feel uniform sound effects, thereby enhancing the user experience.
In some embodiments, a plurality of the acoustic devices 210 may be disposed within the application scenario 300, such as two acoustic devices 210 respectively disposed in front of the listener 120 on the left and right sides to provide surround sound while providing height information for the surround sound through the waveguide structure 213 of the acoustic devices 210. Furthermore, in some embodiments, a plurality of speaker drivers 211 may also be provided within the acoustic device 210, some of the plurality of speaker drivers 211 being primarily for emitting sound traveling directly to a listening location, which may be provided with height cue information after adjustment by the waveguide structure 213. Another part of the plurality of speaker drivers is mainly used for emitting sound which needs to be reflected to travel to a listening position, and the sound can be provided with height prompting information after being reflected. The speaker drivers may not be disposed facing the listener 120 (e.g., when a wall or ceiling is provided, the speaker drivers may face the wall or ceiling) to reduce the portion directly heard by the listener 120 due to sound wave dispersion, ensuring the effect of the head-related transfer function.
It should be appreciated that the above description of the acoustic device 210 is merely exemplary and does not limit the structure of the acoustic device 210 and its application in other similar scenarios. For example, in some alternative embodiments, the waveguide structure of the acoustic device 210 may not necessarily have a second off-axis response, while ensuring that it has a first frequency response corresponding to sound traveling directly to the listening position, in which case it may still be ensured that the sound heard first by the listener contains height-cue information.
Fig. 6 is a schematic view of an application scenario of an acoustic device according to other embodiments of the present application.
The application scenario 300 shown in fig. 6, similar to fig. 5, includes the listener 120 and the acoustic device 210, except that the application scenario 300 simulates an indoor environment, including a ceiling, a floor, and a surrounding wall, and reflects when encountering the ceiling, the floor, and the surrounding wall during sound diffusion. It is understood that the sound generated by the acoustic device 210 and traveling directly to the listening position without being reflected, and the sound traveling to the listening position after being reflected by the ceiling, the ground and the surrounding wall surface can be heard by the listener 120 in the application scenario 300.
The waveguide structure 213 of the acoustic device 210 has: the first frequency response corresponding to sound emitted from the speaker driver 211 traveling directly to the listening position, i.e. the first frequency response corresponding to sound waves 312, may be denoted as Hdir(ω). Since the sound waves 312 are offset from the speaker driver 211 axis at a first angle, the first frequency response may also be referred to as a first off-axis response. The first frequency response may be related to a head-related transfer function. In this case, it will be appreciated that the waveguide structure of the acoustic device 210 conditions the sound waves 312 emitted by the acoustic device, imposing a first frequency response on the sound traveling directly to the listening position, with the effect equivalent to adding a head-related transfer function to the sound traveling directly to the listening position. The head-related transfer function may provide a high level of cues for sound traveling directly to the listening position (i.e., sound waves 312) to simulate sound from above the listening environment.
Further optionally, the waveguide structure 213 of the acoustic device 210 may further have: the second frequency response corresponding to the sound emitted from the speaker driver 211 that needs to travel in reflection to the listening position, i.e. the second frequency response corresponding to sound waves 314 (ceiling reflection), 315 (wall reflection, including back wall reflection) and 316 (ground reflection), can be denoted as HSP(ω). Since sound waves 314, 315, and 316, respectively, correspond to different angles off the axis of the speaker driver, in some embodiments, the second frequency response may be an average response of the plurality of angles off the axis of the speaker driver, i.e., the second frequency response may collectively reflect the waveguide structure213 to the sound emitted at multiple angles on the speaker driver 211.
In some embodiments, the ratio of the first frequency response and the second frequency response is equal to the head-related transfer function (for simplicity, the head-related transfer function with height cue information at an elevation angle of 45 ° is taken as an example) that is:
considering that no head-related transfer function is added to the source audio information x (ω) in the electronic domain in the application scenario 300, the sound heard by the listener 120 at the listening position can be expressed as:
y(ω)＝x(ω)·Hdir(ω)+x(ω)·HSP(ω) (10)
wherein x (ω). Hdir(ω) represents the direct-arriving sound heard by the listener 120 at the listening position, x (ω) · HSP(ω) represents the sum of the reflected sounds heard by the listener 120 at the listening position.
Substituting equation (9) into equation (10) can result in:
generally, the radiated power of the acoustic device 210 may be indicative of the radiation of the acoustic device 210 in all directions, including different angles away from the axis of the speaker driver. Thus, in some embodiments, the second frequency response that collectively reflects the tuning of sound emitted at multiple angles on the speaker driver 211 by the waveguide structure 213 corresponds to the power response of the acoustic device 210. In some embodiments, the goal of the power response is to be as smooth as possible for the speaker driver 211 designer to provide a listening experience that is as smooth as possible. On this premise, the second frequency response H is considered to provide a smooth response for sounds emitted from all angles to ensure good sound qualitySP(ω) may be nearLooking like 1, equation (11) can be written as:
wherein the content of the first and second substances,
representing sounds arriving first to the listener 120 with height cues, and x (ω) representing sounds arriving later to the listener 120 location without height cues but closer to the content of the source audio. Therefore, as can be seen from equation (12), in this application scenario 300, although the acoustic device is located in front of the listener 120, it can bring the spatial experience that the sound reaches the listener 120 from above the listening environment to the listener 120, and at the same time, the fidelity of the sound information is high and the listening experience is smooth.
It should be appreciated that the above description of the acoustic device 210 is merely exemplary and does not limit the structure of the acoustic device 210 and its application in other similar scenarios. For example, in some alternative embodiments, the waveguide structure of the acoustic device 210 may not necessarily have a second off-axis response, while ensuring that it has a first frequency response corresponding to sound traveling directly to the listening position, in which case it may still be ensured that the sound heard first by the listener contains height-cue information.
The beneficial effects that the embodiment of the application may bring include but are not limited to: (1) by adding sound effects in the acoustic domain, the cost is greatly reduced compared to schemes added in the electronic domain; (2) by the arrangement of the waveguide structure 213, it is ensured that the user can definitely feel the height cue provided by the head-related transfer function; (3) by the configuration of the speaker driver 211 and the waveguide structure 213, the fidelity of the sound information is high while the height cue information is received.
It is to be noted that different embodiments may produce different advantages, and in different embodiments, any one or combination of the above advantages may be produced, or any other advantages may be obtained.
Having thus described the basic concept, it will be apparent to those skilled in the art that the foregoing detailed disclosure is to be considered merely illustrative and not restrictive of the broad application. Various modifications, improvements and adaptations to the present application may occur to those skilled in the art, although not explicitly described herein. Such modifications, improvements and adaptations are proposed in the present application and thus fall within the spirit and scope of the exemplary embodiments of the present application.
Also, this application uses specific language to describe embodiments of the application. Reference to "one embodiment," "an embodiment," and/or "some embodiments" means a feature, structure, or characteristic described in connection with at least one embodiment of the application. Therefore, it is emphasized and should be appreciated that two or more references to "an embodiment" or "one embodiment" or "an alternative embodiment" in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, some features, structures, or characteristics of one or more embodiments of the present application may be combined as appropriate.
Similarly, it should be noted that in the preceding description of embodiments of the application, various features are sometimes grouped together in a single embodiment, figure, or description thereof for the purpose of streamlining the disclosure aiding in the understanding of one or more of the embodiments. This method of disclosure, however, is not intended to require more features than are expressly recited in the claims. Indeed, the embodiments may be characterized as having less than all of the features of a single embodiment disclosed above.
Finally, it should be understood that the embodiments described herein are merely illustrative of the principles of the embodiments of the present disclosure. Other variations are also possible within the scope of the present description. Thus, by way of example, and not limitation, alternative configurations of the embodiments of the specification can be considered consistent with the teachings of the specification. Accordingly, the embodiments of the present description are not limited to only those embodiments explicitly described and depicted herein.
Claims (10)
1. An acoustic device, comprising:
a speaker driver and a waveguide structure; the waveguide structure is disposed around the speaker driver, and a surface of the waveguide structure forms a plurality of curved structures arranged radially along the speaker driver, the speaker driver being configured to play at least one of surround sound audio or immersive audio;
the waveguide structure has:
a first frequency response corresponding to sound emanating from the speaker driver traveling directly to a listening position such that a head-related transfer function is added to the sound emanating from the speaker driver traveling directly to the listening position, the head-related transfer function providing a high cue for sound traveling directly from the speaker driver position to the listening position simulating sound from above a listening environment.
2. The acoustic apparatus of claim 1, wherein the waveguide structure further has:
a second frequency response corresponding to sound emitted from the speaker driver that is required to travel in reflection to a listening position such that the sound emitted from the speaker driver that is required to travel in reflection to a listening position does not have height cue information, wherein the second frequency response is a smooth curve in the frequency domain.
3. An acoustic device according to claim 2, wherein:
the ratio of the first frequency response and the second frequency response is equal to the head-related transfer function.
4. An acoustic device according to claim 2, wherein:
the first frequency response is a first off-axis response at a first angle from the speaker driver axis and the second frequency response is a second off-axis response at a second angle from the speaker driver axis.
5. An acoustic device according to claim 2, wherein:
the first frequency response is a first off-axis response at a first angle from the speaker driver axis, and the second frequency response is an average response over a plurality of angles from the speaker driver axis.
6. An acoustic device according to claim 5, wherein:
the second frequency response corresponds to a power response of the acoustic device.
7. An acoustic device according to claim 1, wherein:
the speaker driver is a tweeter driver.
8. An acoustic device according to claim 1, wherein:
the loudspeaker driver comprises a driver cone and a cone dustproof cover, and the waveguide is sleeved on the outer sides of the driver cone and the cone dustproof cover.
9. An acoustic device according to claim 1, wherein:
each curved structure of the waveguide structure surface is symmetrically distributed with respect to the axis of the speaker driver.
10. An audio system, characterized by:
the audio system comprising an acoustic device according to any of claims 1 to 9; the audio system is used to process mixing, rendering, and playback of source audio information in the audio system, including one or more computers or processing devices executing software instructions.
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| US10397694B1 (en) * | 2018-04-02 | 2019-08-27 | Sonos, Inc. | Playback devices having waveguides |
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| CN106416293A (en) * | 2014-06-03 | 2017-02-15 | 杜比实验室特许公司 | Audio speakers having upward firing drivers for reflected sound rendering |
| CN106605415A (en) * | 2014-06-03 | 2017-04-26 | 杜比实验室特许公司 | Passive and active virtual height filter systems for upward firing drivers |
| CN109769165A (en) * | 2017-11-09 | 2019-05-17 | 哈曼国际工业有限公司 | External ear formula Headphone device and method |
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