CN113596647B

CN113596647B - Sound output device and method for adjusting sound image

Info

Publication number: CN113596647B
Application number: CN202010366969.6A
Authority: CN
Inventors: 付峻江; 张磊; 廖风云; 齐心
Original assignee: Shenzhen Voxtech Co Ltd
Current assignee: Shenzhen Voxtech Co Ltd
Priority date: 2020-04-30
Filing date: 2020-04-30
Publication date: 2024-05-28
Anticipated expiration: 2040-04-30
Also published as: CN113596647A

Abstract

The application provides a sound output device and a method for adjusting sound image. The method for adjusting the sound image comprises the following steps: acquiring the volume difference of the first sound wave and the second sound wave; and adjusting a time difference between the first acoustic wave and the second acoustic wave sounds. The sound output device and the method for adjusting the sound image can correct the deviation of the sound image perceived by a user due to the quality difference of the first mechanical structure and the second mechanical structure.

Description

Sound output device and method for adjusting sound image

Technical Field

The present application relates to the field of acoustics, and in particular, to a sound output device and a method for adjusting sound images.

Background

When the bone conduction earphone works, the vibration amplitude of the bone conduction loudspeaker is positively correlated with the volume generated by the bone conduction loudspeaker. Wherein, the shell quality of bone conduction speaker has obvious influence to the amplitude of its vibration, and then influences the volume that the speaker produced. In the product design of bone conduction headphones, it is sometimes necessary to arrange additional functional modules, such as a headset microphone (a microphone with an added extension pole), keys, etc., on one side of the bone conduction speaker. Keys arranged on the bone conduction speaker change the mass distribution on the bone conduction speaker, thereby affecting the volume generated by the speaker. Meanwhile, as the functional modules such as the headset microphone or the keys are only arranged on one side, and the other side is not arranged, the volumes of the speakers on two sides are inconsistent (the volume of the speaker on one ear is larger than that of the speaker on the other ear is smaller), and the sound image is offset. If the volumes of the speakers at the left side and the right side are different greatly, the hearing of a user can be damaged after long-term use. Therefore, the sound image needs to be adjusted so as to be centered, and/or the volume of the speakers at the two sides of the earphone needs to be adjusted so that the volumes of the speakers at the two sides are consistent.

Disclosure of Invention

The following presents a simplified summary of the application in order to provide a basic understanding of some aspects of the application. It should be understood that this section is not intended to identify key or critical elements of the application or to delineate the scope of the application. Its purpose is to present some concepts of the application in a simplified form. Further details will be explained in more detail in the rest of the application.

As previously described, for bone conduction ear phones, the functional module attached to the bone conduction speaker on one side increases the mass of the bone conduction speaker housing, resulting in a decrease in the volume of the speaker on that side and a difference in the volume of the bone conduction ear phones on the left and right sides. When the volume difference of the earphones at the left side and the right side is large, the sound image of the earphones can be obviously deviated, and even hearing damage can be caused after long-term use.

In order to solve the technical problems of volume difference and sound image offset caused by uneven quality of speakers at two sides of a bone conduction earphone, the application discloses a sound output device, which comprises: a signal processing circuit that generates a first electrical signal and a second electrical signal based on the target sound information at a run time; the first loudspeaker is electrically connected with the signal processing circuit, and is used for receiving a first electric signal from the signal processing circuit and converting the first electric signal into a first sound wave when in operation; and a second speaker electrically connected to the signal processing circuit, and operative to receive a second electrical signal from the signal processing circuit and to convert the second electrical signal into a second acoustic wave, wherein the sound output device requires a first length of time to convert the target sound information into the first acoustic wave and a second length of time to convert the target sound information into the second acoustic wave, the first length of time being one time difference shorter than the second length of time.

In some embodiments, the volume of sound waves output by the first speaker is less than the volume of sound waves output by the second speaker at the same amplitude and frequency of electrical signal inputs.

In some embodiments, the difference between the volume of the first sound wave and the volume of the second sound wave is no greater than 3dB at the same amplitude and frequency of the electrical signal input.

In some embodiments, the first speaker generates the first sound wave by exciting a first mechanical structure; and the second speaker generating a second sound wave by exciting a second mechanical structure, wherein the mass of the first mechanical structure is greater than the mass of the second mechanical structure, resulting in a volume of sound waves output by the first speaker being less than a volume of sound waves output by the second speaker at the same amplitude and frequency of electrical signal input.

In some embodiments, the first speaker comprises at least one of a first bone conduction speaker and a first air conduction speaker; and the second speaker includes at least one of a second bone conduction speaker and a second air conduction speaker.

In some embodiments, the time difference occurs during the conversion of the target sound information into the first electrical signal and the second electrical signal by the sound output device.

In some embodiments, the time difference occurs during the first speaker converting the first electrical signal into the first sound wave and the second speaker converting the second electrical signal into the second sound wave.

In some embodiments, the time difference is not greater than 3ms.

The application also discloses a method for adjusting the sound image. The method of adjusting an acoustic image is configured to adjust acoustic images of a first speaker and a second speaker of an acoustic output device, comprising: acquiring the volume difference of the first sound wave and the second sound wave; and adjusting the time difference.

In some embodiments, the difference in volume of the first sound wave and the second sound wave is no greater than 3dB.

In some embodiments, said adjusting the time difference of said first acoustic wave and said second acoustic wave comprises: a phase difference of the first sound wave and the second sound wave is adjusted.

In summary, aiming at the technical problems of volume difference and sound image offset caused by uneven quality of speakers at two sides of a bone conduction earphone, the application provides a sound output device and a method for adjusting sound image.

Drawings

The following drawings describe in detail exemplary embodiments disclosed in the present application. Wherein like reference numerals refer to like structure throughout the several views of the drawings. Those of ordinary skill in the art will understand that these embodiments are non-limiting, exemplary embodiments, and that the drawings are for illustration and description only and are not intended to limit the scope of the present disclosure, as other embodiments may equally well accomplish the inventive intent in this disclosure. It should be understood that the drawings are not to scale. Wherein:

fig. 1 is a schematic view showing an external appearance of a sound output apparatus according to some embodiments of the present application;

fig. 2 is a schematic diagram showing the structure of a sound output apparatus according to some embodiments of the present application;

FIG. 3 illustrates a schematic diagram of an electromagnetic excitation device provided in accordance with some embodiments of the present application;

fig. 4 illustrates a schematic diagram of a bone conduction speaker provided in accordance with some embodiments of the present application;

fig. 5 illustrates a vibration model schematic of a bone conduction speaker provided in accordance with some embodiments of the present application;

FIG. 6 illustrates vibration test results for an operational housing provided in accordance with some embodiments of the present application;

Fig. 7 illustrates a schematic diagram of a moving coil speaker according to some embodiments of the present application;

Fig. 8 is a flowchart of a method for adjusting volume according to an embodiment of the present application; and

Fig. 9 shows a flowchart of a method of adjusting an acoustic image according to an embodiment of the present application.

Detailed Description

The following description provides specific applications and requirements of the application to enable any person skilled in the art to make and use the application. These and other features of the present disclosure, as well as the operation and function of the related elements of structure, as well as the combination of parts and economies of manufacture, may be significantly improved upon in view of the following description. With reference to the accompanying drawings, all of which form a part of this disclosure. It is to be expressly understood, however, that the drawings are for the purpose of illustration and description only and are not intended as a definition of the limits of the disclosure. Various modifications to the disclosed embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments and applications without departing from the spirit and scope of the disclosure. Thus, the present disclosure is not limited to the embodiments shown, but is to be accorded the widest scope consistent with the claims.

In the present application, bone conduction sound waves refer to sound waves (also called bone conduction sounds) in which mechanical vibrations are conducted into the ear via bones, and air conduction sound waves refer to sound waves (also called air conduction sounds) in which mechanical vibrations are conducted into the ear via air.

The application provides a volume adjusting method. The volume adjustment method may be used to adjust the volume of sound waves output by the sound output device. The acoustic waves may include bone-conduction acoustic waves and/or air-conduction acoustic waves. The sound output device may include, but is not limited to, headphones, hearing aids, helmets, and the like. The headset may include, but is not limited to, a wired headset, a wireless headset, a bluetooth headset, and the like. The headphones may include, but are not limited to, bone conduction speakers, air conduction speakers.

Fig. 1 shows an external schematic view of a sound output device 300 provided according to an embodiment of the application. Fig. 2 shows a schematic structural diagram of a sound output device 300 according to an embodiment of the present application. Referring to fig. 2, the sound output apparatus 300 may include a first speaker 310, a second speaker 320, and a signal processing circuit 330.

The signal processing circuit 330 may receive the target sound information 10, process the target sound information 10, and generate the first electrical signal 11 and the second electrical signal 12.

The target sound information 10 may include video, audio files having a specific data format, or data or files that can be converted into sound through a specific approach. The target audio information 10 may be obtained from a storage unit of the audio output apparatus 300 itself, or may be obtained from an information generation, storage, or transmission system other than the audio output apparatus 300. The target sound information 10 may include one or more combinations of electrical, optical, magnetic, mechanical, etc. The target sound information 10 may be from a single source or multiple sources. The plurality of signal sources may or may not be correlated. In some embodiments, the signal processing circuit 330 may obtain the target sound information 10 in a number of different ways. The acquisition of the target sound information 10 may be wired or wireless, and may be real-time or delayed. For example, the audio output device 300 may receive the target audio information 10 by wired or wireless means, or may directly obtain data from a storage medium, and generate the target audio signal 10. As another example, the sound output apparatus 300 may include therein a component having a sound collection function, by picking up sounds in the environment and converting mechanical vibrations of the sounds into an electrical signal, and by amplifying the processor to obtain an electrical signal satisfying specific requirements. In some embodiments, the wired connection may include a metallic cable, an optical cable, or a hybrid metallic and optical cable, such as, for example, a coaxial cable, a communications cable, a flex cable, a spiral cable, a nonmetallic sheath cable, a metallic sheath cable, a multi-core cable, a twisted pair cable, a ribbon cable, a shielded cable, a electrical core cable, a twinax cable, parallel twinax wires, twisted pair wires, or the like. The above-described examples are for convenience only and the medium of the wired connection may be other types of transmission carriers, for example, other electric signals or optical signals, etc. The wireless connection may include radio communication, free space optical communication, acoustic communication, electromagnetic induction, and the like. Wherein the radio communications may include IEEE802.11 series standards, IEEE802.15 series standards (e.g., bluetooth technology, cellular technology, etc.), first generation mobile communications technology, second generation mobile communications technology (e.g., FDMA, TDMA, SDMA, CDMA, SSMA, etc.), general packet radio service technology, third generation mobile communications technology (e.g., CDMA2000, WCDMA, TD-SCDMA, wiMAX, etc.), fourth generation mobile communications technology (e.g., TD-day E, FDD-LTE, etc.), satellite communications (e.g., GPS technology, etc.), and, Near Field Communication (NFC) and other technologies operating in the ISM band (e.g., 2.4GHz, etc.); free space optical communications may include visible light, infrared signals, and the like; the acoustic communication may include acoustic waves, ultrasonic signals, etc.; electromagnetic induction may include near field communication techniques, and the like. The above described examples are for convenience of illustration only and the medium of the wireless connection may also be of other types, e.g. Z-wave technology, other charged civilian and military radio bands, etc. For example, as some application scenarios of the present application, the sound output apparatus 300 may acquire the target sound information 10 from other devices through bluetooth technology.

In some embodiments, in order for the first acoustic wave 21 and the second acoustic wave 22 to have specific output characteristics (e.g., frequency, phase, amplitude, etc.), the signal processing circuit 330 may process the target sound information 10 such that the first electrical signal 11 and the second electrical signal 12 output by the signal processing circuit 330 respectively contain specific frequency components.

In some embodiments a number of filters/filter banks 331 may be provided in the signal processing circuit 330. The plurality of filters/filter banks 331 may process the received electrical signals and output electrical signals containing different frequencies. The filter/filter bank 331 includes, but is not limited to, analog filters, digital filters, passive filters, active filters, and the like. In some embodiments, a dynamic range controller 332 may be provided in the signal processing circuit 330. The dynamic range controller 332 may be configured to compress and amplify the input signal to make the sound softer or louder. In some embodiments, an active leakage reduction circuit 333 may be provided in the signal processing circuit 330 to reduce leakage of the sound output device 300. In some embodiments, a feedback circuit 334 may be provided in the signal processing circuit 330. The feedback circuit 334 may feed back sound field information to the signal processing circuit 330. In some embodiments, a power adjustment circuit 335 may be provided in the signal processing circuit 330 to adjust the amplitude of the received electrical signal. The power conditioning circuit 335 may include a power amplification circuit to amplify the signal to the first electrical signal 11 and/or the second electrical signal 12. The power conditioning circuit 335 may also include a power attenuation circuit to attenuate the signal amplitude of the first electrical signal 11 and/or the second electrical signal 12. In some embodiments, an equalizer 338 may be provided in the signal processing circuit 330. The equalizer 338 may be configured to individually gain or attenuate the received signal in accordance with a particular frequency band. In some embodiments, a frequency divider circuit 339 may be included in the signal processing circuit 330. The frequency dividing circuit may decompose the received electrical signal into a high frequency signal component and a low frequency signal component.

The first speaker 310 is electrically connected to the signal processing circuit 330. The first speaker 310 may receive the first electrical signal 11 from the signal processing circuit 330 and convert the first electrical signal 11 into the first sound wave 21. The first speaker 310 may be a transducer device. In some embodiments, the first speaker 310 may convert the received first electrical signal 11 into mechanical vibrations. Further, the first acoustic wave 21 is generated by the mechanical vibration. For example, the first speaker 310 may include a first mechanical structure 311 and a first excitation device 312. In some embodiments, the first speaker 310 may be a bone conduction speaker; the first speaker 310 may also include an air conduction speaker, or a combination of bone and air conduction speakers.

The first excitation device 312 may be an input of the energy transforming device. The first excitation device 312 receives the first electrical signal 11 from the signal processing circuit 330 and converts the first electrical signal 11 into a first excitation. The first excitation excites the first mechanical structure 311 to vibrate. That is, the first speaker 310 converts the electric energy of the received first electric signal 11 into mechanical energy of vibration of the first mechanical structure 311 through the first excitation device 312 and the first mechanical structure 311.

The first excitation means 412 generate said first excitation to excite the first mechanical structure 411 to vibrate. In some embodiments, the first excitation device 412 may be an electromagnetic excitation device. The first excitation may be a magnetic field force, an electromagnetic force and/or an ampere force generated by the electromagnetic excitation device. Of course, the first excitation device 412 may be other types of excitation devices, and the present application is not limited in particular. The excitation means receives the first electrical signal 11 from the signal processing circuit 430 and generates a first excitation. The means for generating the first excitation may include, but is not limited to, moving coil, electrostatic, piezoelectric, moving iron, pneumatic, electromagnetic, and the like.

By way of example, fig. 3 shows a schematic structural diagram of a first excitation device 412 provided in accordance with an embodiment of the present application. The first excitation device 412 shown in fig. 3 may be an electromagnetic excitation device. Specifically, the first excitation device 412 may include a magnetic member 610 and a coil 620.

The magnetic member 610 may generate a magnetic field. For example, the magnetic member 610 may be magnetic. In some embodiments, the magnetic properties may be constant. The magnetic member 610 may include or be fabricated from a permanent magnet. The permanent magnet may be a natural magnet or an artificial magnet. By way of example, the permanent magnets may include, but are not limited to, neodymium-iron-boron magnets, samarium-cobalt magnets, alnico magnets, and the like. The permanent magnet should have a coercive force, remanence and maximum magnetic energy product as high as possible to ensure that the permanent magnet has stable magnetism and is capable of storing maximum magnetic energy.

The coil 620 may be wound around groups of windings in a certain direction. The coil 620 may be disposed within the magnetic field generated by the magnetic member 610. The coil 620 may include a first end 621 and a second end 622. The electrical signal may enter the coil 620 from the first end 621, flow through the coil 620, and exit the coil 620 from the second end 622 in the form of an electrical current.

As is known from electromagnetic knowledge, energized coil 620 is subjected to ampere forces in a magnetic field. The magnitude of the ampere force may be determined by f=b·i·l. Where F represents the magnitude of the ampere force received by the coil 620; the direction of F may be determined according to the ampere rule. The F-drive coil 620 vibrates. The coil 620 may be connected to the mechanical structure 630, and further, the coil 620 drives the mechanical structure 630 to vibrate. As an example, the mechanical structure 630 may be the first mechanical structure 311 that generates the first acoustic wave 21. That is, F may excite the first mechanical structure 311 to generate vibration as an external excitation signal.

B is the magnetic field strength of the magnetic field generated by the magnetic member 610. The magnitude of the magnetic field strength of the magnetic field generated by the magnetic member 610 is related to the material of the magnetic member 610. In some embodiments, the magnitude of the magnetic field B generated by the magnetic element 610 is positively correlated with the coercivity, remanence, and maximum magnetic energy product of the magnetic element 610.

I is the magnitude of the current passing in coil 620. I is related to the electrical signal received by the first excitation device 412. Typically, the electrical signal will be input to the coil 620 in the form of a pulsed voltage. The magnitude of the pulse voltage (i.e., the electrical signal input to electromagnetic excitation device 600) between first end 621 and second end 622 of coil 620 is denoted by Ut. The current I flowing through the coil 620 may be represented as i=u _t/R. Where R represents the magnitude of the resistance between the first end 621 and the second end 622. While, based on physical knowledge, the resistance between the first end 621 and the second end 622 may be based onAnd (5) calculating to obtain the product. Where ρ represents the resistivity of the windings of the coil 620; l represents the length of the coil 620; s denotes a diameter of a winding wire of the coil 620.

In summary, the magnitude of the excitation F (i.e., the amperage applied to the coil) generated in the first excitation device 412 is found to be:

With continued reference to fig. 2, the first mechanical structure 311 may be an output of the energy conversion device. The first mechanical structure 311 vibrates to produce the first acoustic wave 21. The first mechanical structure 311 may generate mechanical vibrations under the influence of the first excitation; further, the first acoustic wave 21 is generated based on the mechanical vibration. In some embodiments, the first mechanical structure 311 may be a component that directly emits sound by vibration when excited. For example, when the first speaker is a bone conduction speaker, the first mechanical structure 311 may be a housing of the bone conduction speaker. And when the first speaker is a moving coil air conduction speaker, the first mechanical structure 311 may include a wool basin or cone of the moving coil air conduction speaker.

Since the first acoustic wave 21 is generated by the vibration of the first mechanical structure 311, in order to analyze the characteristics of the first acoustic wave 21, it is necessary to analyze the vibration process of the first mechanical structure 311. Next, the present application takes the first speaker 310 as an example of the bone conduction speaker to analyze the vibration process of the first mechanical structure 311.

Fig. 4 illustrates a schematic diagram of a bone conduction speaker 100 provided in accordance with some embodiments of the present application. Bone conduction speaker 100 may include a housing 120 and a magnetic circuit 130.

The magnetic circuit 130 may act as an excitation means to generate an excitation f. The magnetic circuit 130 and the housing 120 are connected by a vibration-transmitting plate 140.

The housing 120 may be attached to the ear hook 110. The point P at the top of the ear hook 110 fits well with the head. Thus, the top ppoint may be considered a fixed point. When bone conduction speaker 100 is in operation, housing 120 may vibrate under excitation f and generate sound waves. Based on the interaction of the forces, the magnetic circuit 130 is also subjected to a force of the same magnitude as f (i.e., "-f" shown in the figures) in opposite directions during the vibration of the housing 120. To facilitate analysis of the relationship between sound waves generated by bone conduction speaker 100 and housing 120 and magnetic circuit 130, housing 120 and magnetic circuit 130 may be reduced to a two-degree-of-freedom vibration system.

Fig. 5 shows a model of a two-degree-of-freedom vibration system provided according to an embodiment of the present application. In the model shown in fig. 5: the mass m ₁ may represent the housing 120; the mass m ₂ may represent the magnetic circuit 130; the elastic connection k ₁ may represent the vibration-transmitting sheet 140; elastic connector k ₂ may represent an ear hook 110. The damping of the elastic connections k ₁ and k ₂ is c ₁ and c ₂, respectively. The housing 120 and the magnetic circuit 130 are subjected to the force f and the force-f, respectively, to generate vibrations. f is the system excitation size; the direction of f is shown in fig. 5. The composite vibration system composed of the shell 120, the magnetic circuit 130, the vibration transmitting sheet 140 and the ear hook 110 is fixed at the point P at the top end of the ear hook 110.

The dynamic analysis is performed by taking the shell 120 and the magnetic circuit 130 as objects, so that a dynamic equation of the two-degree-of-freedom vibration model shown in fig. 5 can be obtained:

From the fourier transform, any stimulus f can be expressed in the frequency domain as the sum of a series of simple harmonic vibrations, thus assuming Wherein F ₀ is the excitation amplitude; the steady state response of the system can be expressed asWherein/>Is the response amplitude.

Bringing F and X into equation (2) yields equation (3).

The mechanical impedance matrix Z (ω) is introduced:

bringing the mechanical impedance matrix Z (omega) into a formula (3), and solving to obtain the response amplitude of the vibration system as follows:

Wherein,

Thus, the response amplitude of the vibration system can be obtained as follows:

The housing 120 vibrates to generate sound waves. Thus, the housing 120 (i.e., the mass m ₁) is analyzed. Bringing the mechanical impedance matrix Z (ω) into equation (4) yields a response amplitude for the housing 120 of:

As can be seen from equation (6), the amplitude X ₁ of the vibration of the housing 120 is also affected by the following parameters: the frequency of excitation F (equal to 1/ω), the amplitude F ₀ of excitation F, the mass m ₁ of the housing 120, the mass m ₂ of the magnetic circuit 130, the stiffness k ₁ and the damping c ₁ of the vibration-transmitting plate 140, and the stiffness k ₂ and the damping c ₂ of the ear-hook 110. For example, the amplitude F ₀ of the excitation F is proportional to the vibration amplitude X ₁ of the housing 120, while keeping the other parameters unchanged. The greater the amplitude F ₀ of the excitation F, the greater the amplitude X ₁ of the housing 120. For another example, the larger the mass m ₁ of the housing 120 of the bone conduction speaker 100, the smaller the amplitude X ₁ of the housing 120, with other parameters maintained unchanged; the larger the mass m ₂ of the magnetic circuit 130, the larger the amplitude X ₁ of the housing 120. Therefore, when the above parameters are changed, the amplitude X ₁ of the housing 120 is also changed. The amplitude X ₁ of the housing 120 is positively correlated with the volume of sound waves generated by vibration of the housing 120 regardless of the difference in transmission medium and transmission distance. The larger the amplitude X ₁, the greater the volume of the sound wave; the smaller the amplitude X ₁, the smaller the volume of the sound wave.

Fig. 6 illustrates vibration test results of the housing 120 during operation of a bone conduction speaker 100, provided in accordance with some embodiments of the present application. In the vibration test, the physical quantity for evaluating the magnitude of vibration or sound volume may include, but is not limited to, the speed, displacement, sound pressure level, and the like of the vibration source. As an example, the acceleration level (unit: dB) of the vibration source was used as the physical quantity for evaluating vibration in the vibration test shown in fig. 6. In fig. 6, the solid line represents a plot of the vibration acceleration level of bone conduction speaker 100 as a function of the frequency of excitation f for a case where the mass of housing 120 is m ₁; the dashed line represents a plot of the vibration acceleration level of bone conduction speaker 100 as a function of the frequency of excitation f after a 50% increase in mass m ₁ of housing 120.

As can be seen in fig. 6, the acceleration level of the vibrations of the housing 120 is related to frequency and mass. The acceleration level of the housing vibration when the housing 120 mass m ₁ becomes 1.5m ₁ does not drop significantly in the low frequency band below 160Hz, but drops by about 3-4dB in both the medium and high frequency bands, relative to the initial housing mass m ₁. That is, the amplitude of the vibration of the housing 120 may decrease by 3-4dB when the mass of the housing 120 increases by 0.5 times in the middle and high frequency bands.

The above conclusion is based on the results obtained by speaker modeling. Within the hearing range of the human ear, low frequencies may refer to frequency bands of substantially 20Hz to 150Hz, medium frequencies may refer to frequency bands of substantially 150Hz to 5KHz, high frequency bands may refer to frequency bands of substantially 5KHz to 20KHz, medium and low frequencies may refer to frequency bands of substantially 150Hz to 500Hz, and medium and high frequencies refer to frequency bands of 500Hz to 5 KHz. Those of ordinary skill in the art will appreciate that the above-described distinction of frequency bands is given by way of example only. The definition of the above frequency bands may vary with different industries, different application scenarios and different classification criteria. For example, in other applications, low frequency may refer to a frequency range of substantially 20Hz to 80Hz, medium and low frequency may refer to a frequency range of substantially 80Hz-160Hz, medium frequency may refer to a frequency range of substantially 160Hz to 1280Hz, medium and high frequency may refer to a frequency range of substantially 1280Hz-2560Hz, and high frequency may refer to a frequency range of substantially 2560Hz to 20 KHz.

It should be noted that, although the foregoing description only describes the relationship between the volume generated by the bone conduction speaker and the mass of the housing, the first speaker 310 of the present application is not limited to the bone conduction speaker. For example, in the case of an air conduction speaker, the performance of the first speaker 310 still satisfies the above analysis.

As an example, fig. 7 shows a schematic structural diagram of a moving coil speaker 500 according to an embodiment of the present application. The moving coil speaker shown in fig. 7 may be an air conduction speaker. In particular, the moving coil speaker 500 may include a magnetic circuit assembly 520, a vibration assembly 530, and a support auxiliary assembly 510.

The support auxiliary assembly 510 may provide support for the vibration assembly 530 and the magnetic circuit assembly 520. The support assistance assembly 510 may include an elastic member 511. The vibration assembly 530 may be fixed to the support auxiliary assembly 510 by the elastic member 511.

The magnetic circuit assembly 520 may convert the electrical signal into an excitation F. The excitation F may act on the vibration assembly 530.

The vibration assembly 530 may vibrate and generate sound waves under the influence of the stimulus F.

By kinetic analysis, it can be derived that: similar to bone conduction speaker 100, the amplitude of vibration assembly 530 in moving coil speaker 500 under excitation F is related to the equivalent mass m, excitation F, damping c, and stiffness k of vibration assembly 530. Where the equivalent mass of the vibration assembly 530 is greater, the amplitude of the vibration is smaller, with the other parameters unchanged. The larger the excitation F, the larger the amplitude of the vibration, with the other parameters unchanged. For brevity, the process of kinetic analysis is not described in detail.

In summary, the volume of the first sound wave 21 generated by the vibration of the first mechanical structure 311 is related to the frequency of the first electric signal 11 and the mass of the first mechanical structure 311. Wherein the greater the mass of the first mechanical structure 311, the lower the volume of the first sound wave 21.

With continued reference to fig. 2, the second speaker 320 is electrically connected to the signal processing circuit 330. The second speaker 320 may receive the second electrical signal 12 from the signal processing circuit 330 and convert the second electrical signal 12 into the second acoustic wave 22. The second speaker 320 may be a transducer device. In some embodiments, the second speaker 320 may convert the received electrical signal into mechanical vibrations. Further, the second sound wave 22 is generated by the mechanical vibration. In some embodiments, the second speaker 320 may include a second mechanical structure 321 and a second excitation device 322. The structure and function of the second mechanical structure 321 may be the same as or similar to the first mechanical structure 311; the structure and function of the second excitation device 322 may be the same as or similar to the first excitation device 312. The structure and function of the second mechanical structure 321 and the second excitation device 322 are not described in detail.

As with the first speaker 310, the volume of the second sound wave 22 generated by the vibration of the second mechanical structure 321 in the second speaker 320 is related to the frequency of the second electrical signal 21 and the mass of the second mechanical structure 321. Wherein the larger the mass of the second mechanical structure 321, the smaller the volume of the second sound wave 22.

With continued reference to fig. 1, in some embodiments, an additional device 940 is provided on one end of the first speaker 310. By way of example, the additional device 940 may include function keys provided on a side housing of the bone conduction headset. By way of example, the additional device 940 may include a headset microphone disposed on a bone conduction headset-side housing. The headset microphone may include, but is not limited to, a base, microphone linkage, microphone, and the like. The arrangement of the headset microphone can improve the conversation quality of the bone conduction earphone. The mass of the additional device 940 is not negligible compared to the mass of the sound output apparatus 300. Since the additional device 940 is provided on a single side of the sound output apparatus 300 (i.e. on one side of the first loudspeaker 310), this may result in the mass of the first mechanical structure 311 in the first loudspeaker 310 being greater than the mass of the second mechanical structure 311 in the second loudspeaker 310. For example, the mass of the shell of the bone conduction speaker provided with the ear microphone on one side is greater than the mass of the shell of the bone conduction speaker not provided with the ear microphone on the other side.

As can be seen from the foregoing description, if the mass of the first mechanical structure 311 is greater than the mass of the second mechanical structure 321 under the same electric signal input without considering the differences of damping, rigidity, etc., the amplitude of the vibration of the first mechanical structure 311 is smaller than the amplitude of the vibration of the second mechanical structure 321. If the difference between the transmission medium and the transmission distance is not considered, the volume of the first sound wave emitted from the first speaker 310 heard by the user is smaller than the volume of the second sound wave emitted from the second speaker 320.

If a difference between the volume of the first sound wave and the volume of the second sound wave (hereinafter referred to as a difference in volume) heard by the user exists for a long time, the hearing of the user may be impaired. In addition (e.g., when the difference in volume of the sound heard by the user's ears is greater than 3dB over a long period of time, damage is caused to the user's ears.) the presence of a difference in volume between the first sound wave and the second sound wave heard by the user also causes an offset between the sound image perceived by the user and the actual sound image. Therefore, the volumes of the first sound wave and the second sound wave need to be adjusted so that the volumes of the first sound wave and the second sound wave are as consistent as possible to avoid hearing impairment and sound image shift caused by the volume difference.

Fig. 8 shows a flowchart of a method S200 for adjusting a volume according to an embodiment of the present application. The process S200 may be used to adjust the volume of sound output by the first speaker 310 and the second speaker 320 of the sound output device 300. The process S200 may also be used to adjust the sound image of the sound output device 300 perceived by the user. Specifically, the process S200 may include: s210, acquiring the volume difference of the first sound wave and the second sound wave; and S220, adjusting the amplitude difference of the first excitation and the second excitation.

S210, acquiring the sound difference of the first sound wave and the second sound wave. In some embodiments, the volume difference is greater than 3dB.

S220, adjusting the amplitude difference of the first excitation and the second excitation. From the foregoing, it is apparent that the mass of the first mechanical structure is greater than the mass of the second mechanical structure, resulting in the amplitude of vibration of the first mechanical structure being less than the amplitude of vibration of the second mechanical structure, further resulting in the volume of the first acoustic wave being less than the volume of the second acoustic wave. Thus, the amplitude of the first mechanical structure may be adjusted by adjusting the amplitude of the first excitation; the amplitude of the second mechanical structure may be adjusted by adjusting the amplitude of the second excitation; and thereby correct for differences in the sound volume due to differences in the mass of the first mechanical structure and the second mechanical structure.

For ease of understanding, in the following description of the present application, the magnitude of the first excitation is represented by F ₁, the magnitude of the second excitation is represented by F ₂, the mass of the first mechanical structure is represented by M ₁, the mass of the second mechanical structure is represented by M ₂, the cross-sectional area of the first coil winding is represented by S ₂, the cross-sectional area of the second coil winding is represented by S ₁, the resistivity of the first coil winding is represented by ρ ₁, the resistivity of the second coil winding is represented by ρ ₂, the magnetic field strength of the first magnetic member is represented by B ₁, the magnetic field strength of the second magnetic member is represented by B ₂, the resistance of the first coil winding is represented by R ₁ (hereinafter referred to as first resistance), and the resistance of the second coil winding is represented by R ₂ (hereinafter referred to as second resistance).

Referring to equations (1) and (6), the first excitation F ₁ and/or the second excitation F ₂ may be adjusted to make the amplitude X ₁ of the vibration of the first mechanical structure 311 consistent with the amplitude X ₂ of the vibration of the second mechanical structure 321, so that the volume of the first sound wave 21 is consistent with the volume of the second sound wave 22.

In some embodiments, the volume of the first acoustic wave 21 may be matched to the volume of the second acoustic wave 22 by adjusting the diameter of the first coil winding and/or the diameter of the second coil winding to obtain the first excitation F ₁ and the second excitation F ₂ of different sizes. Due to M ₁＞M₂, S ₁＞S₂ may be caused by increasing the diameter of the first coil wire and/or decreasing the diameter of the second coil wire. According to equation (1), the first excitation means 312 produces a first excitation F ₁ that is greater than the second excitation means 422 produces a second excitation F ₂. In conjunction with equation (6), the first stimulus F ₁ is greater than the second stimulus F ₂, which can bring X ₁ into agreement with X ₂. Then, the power of the first sound wave 21 is the same as the power of the second sound wave 22, and the volume of the first sound wave 21 heard by the user is the same as the volume of the second sound wave 22. This corrects for the difference in the sound volume due to the difference in mass (M ₁＞M₂) between the first mechanical structure 311 and the second mechanical structure 321. Further, the sound image shift due to the volume difference is also avoided.

Further, the method of adjusting the volume by adjusting the diameter of the coil keeps the overall size of the coil unchanged while making the output volume uniform. In this way, the structure and dimensions of the various components in the sound output device can be maintained.

As an example, when the earphone requires a larger maximum volume, a bone conduction speaker with an additional device uses a coil with a wire having a wire diameter thicker than that of a speaker without an additional device. For example, the ratio of the wire diameters of the thick wire used for the speaker coil with the additional device to the wire used for the speaker coil without the additional device is not less than any value or a range between any two values: 1.01, 1.02, 1.03, 1.04, 1.05, 1.06, 1.07, 1.08, 1.09, 2.0.

As an example, when the earphone requires relatively small power consumption, the bone conduction speaker on the side without the additional device uses a coil with a wire diameter smaller than that of the speaker on the side with the additional device. As an example, the ratio of the wire diameters of the thin wire used for the no-additional-device-side speaker coil to the wire used for the no-additional-device-side speaker coil is not greater than any value or a range between any two values: 0.90, 0.91, 0.92, 0.93, 0.94, 0.95, 0.96, 0.97, 0.98, 0.99.

In addition, the resistivity of the first coil and/or the resistivity of the second coil can be adjusted to obtain the first excitation F ₁ and the second excitation F ₂ with different magnitudes, so that the volume of the first sound wave 21 is consistent with the volume of the second sound wave 22. Because of M ₁＞M₂, ρ ₁＜ρ₂ can be made by decreasing the resistivity ρ ₁ of the first coil and/or increasing the resistivity ρ ₂ of the second coil. As an example, a particular winding material may be selected such that ρ ₁＜ρ₂ is. With the other arguments unchanged, the first excitation F ₁ generated by the first excitation device 312 is greater than the second excitation F ₂ generated by the second excitation device 422, according to equation (1). In conjunction with equation (6), the first stimulus F ₁ is greater than the second stimulus F ₂, which can bring X ₁ into agreement with X ₂. Then, the power of the first sound wave 21 is the same as the power of the second sound wave 22, and the volume of the first sound wave 21 heard by the user is the same as the volume of the second sound wave 22. This corrects for the difference in the sound volume due to the difference in mass (M ₁＞M₂) between the first mechanical structure 311 and the second mechanical structure 321. Further, the sound image shift due to the difference in the sound volume is also corrected.

In addition, the magnetic field intensity B ₁ of the first magnetic element and/or the magnetic field intensity B ₂ of the second magnetic element can be adjusted to obtain the first excitation F ₁ and the second excitation F ₂ with different magnitudes, so that the volume of the first sound wave 21 is consistent with the volume of the second sound wave 22. Due to M ₁＞M₂, B ₁＞B₂ may be achieved by increasing the magnetic field strength of the first magnetic element B ₁ and/or decreasing the magnetic field strength of the second magnetic element B ₂. With the other arguments unchanged, the first excitation F ₁ generated by the first excitation device 312 is greater than the second excitation F ₂ generated by the second excitation device 422, according to equation (1). In conjunction with equation (6), the first stimulus F ₁ is greater than the second stimulus F ₂, which can bring X ₁ into agreement with X ₂. Then, the power of the first sound wave 21 is the same as the power of the second sound wave 22, and the volume of the first sound wave 21 heard by the user is the same as the volume of the second sound wave 22. This corrects for the difference in the sound volume due to the difference in mass (M ₁＞M₂) between the first mechanical structure 311 and the second mechanical structure 321. Further, the sound image shift due to the difference in the sound volume is also corrected.

The size of the first magnetic member may be increased and/or the size of the second magnetic member may be decreased to make B ₁＞B₂.

For example, a magnetic member made of a material having different magnetic properties may be selected for B ₁＞B₂. For example, the first magnetic part is made of a material with stronger magnetism; the second magnetic part is made of a material with weaker magnetism. In some embodiments, the remanence of the first magnetic member is greater than the remanence of the second magnetic member such that the magnetic field strength B ₁ generated by the first electromagnetic excitation device is greater than the magnetic field strength B ₂ generated by the second electromagnetic excitation device. In some embodiments, the coercivity of the first magnetic element is greater than the coercivity of the second magnetic element such that the magnetic field strength B ₁ generated by the first electromagnetic actuation device is greater than the magnetic field strength B ₂ generated by the second electromagnetic actuation device. In some embodiments, the magnetic energy product of the first magnetic member is greater than the magnetic energy product of the second magnetic member such that the magnetic field strength B ₁ generated by the first electromagnetic excitation device is greater than the magnetic field strength B ₂ generated by the second electromagnetic excitation device.

In some embodiments, the first and second excitation F ₁ and F ₂ may be obtained by adjusting the magnitude of the first resistor R ₁ and/or the second resistor R ₂ to obtain different magnitudes of the first and second excitation F ₁ and F ₂, so that the volume of the first sound wave 21 is consistent with the volume of the second sound wave 22. In the present application, the first resistor R ₁ refers to the overall resistance of the first speaker, including the internal resistance of the first speaker and possible additional resistance; the second resistor R ₂ refers to the overall resistance of the second speaker, including the internal resistance of the second speaker and possible additional resistance. Due to M ₁＞M₂, R ₁＜R₂ may be enabled by decreasing the first resistance R ₁ and/or increasing the second resistance R ₂. With the other arguments unchanged, the first excitation F ₁ generated by the first excitation device 312 is greater than the second excitation F ₂ generated by the second excitation device 422, according to equation (1). In conjunction with equation (6), the first stimulus F ₁ is greater than the second stimulus F ₂, which can bring X ₁ into agreement with X ₂. Then, the power of the first sound wave 21 is the same as the power of the second sound wave 22, and the volume of the first sound wave 21 heard by the user is the same as the volume of the second sound wave 22. This corrects for the difference in the sound volume due to the difference in mass (M ₁＞M₂) between the first mechanical structure 311 and the second mechanical structure 321. As an example, when the earphone has no particularly stringent requirements for maximum volume and power consumption, the bone conduction speaker on the side without additional devices (such as a headset microphone) is connected in series with a resistor. As an example, the resistance of the series resistance of the bone conduction speaker on the side without the additional device is not less than 1Ω. It should be noted that the series resistor is not necessarily a separate resistor device, and the same effect can be achieved by controlling the resistance of the wire (e.g., the post-hanging wire) used in the circuit.

In addition, the difference in the sound volume caused by the difference in the mass of the first mechanical structure 311 and the second mechanical structure 321 can be corrected by connecting a resistor in series outside the second coil so that the first resistor R ₁ is smaller than the second resistor R ₂ (i.e., R ₁＜R₂). Furthermore, by adopting a method of connecting resistors in series and externally connecting the resistors, materials are not required to be added in the production and design processes, and the influence on the production and design is small.

In addition, the difference in the sound volume caused by the difference in the mass of the first mechanical structure 311 and the second mechanical structure 321 can be corrected by directly reducing the resistance R ₁ of the first coil and/or increasing the resistance R ₂ of the second coil so that the first resistance R ₁ is smaller than the second resistance R ₂ (i.e., R ₁＜R₂). According to the formula r=ρl/S, in some embodiments, the resistance of the first coil may be made smaller than the resistance of the second coil by decreasing the resistivity of the first coil and/or increasing the resistivity of the second coil. In some embodiments, the resistance of the first coil may be made smaller than the resistance of the second coil by increasing the length of the windings of the first coil and/or decreasing the length of the windings of the second coil. In some embodiments, the resistance of the first coil may be made smaller than the resistance of the second coil by reducing the diameter of the windings of the first coil and/or increasing the diameter of the windings of the second coil. The first coil and/or the second coil may also change in mass when the resistivity, the winding length, and/or the winding diameter of the first coil and/or the second coil are increased and/or decreased. The mass of the first and second coils will also affect the vibrations of the first and second mechanical structures. Therefore, when adjusting the parameters such as resistivity, winding length and/or winding diameter, the influence of other parameters needs to be considered, so that the amplitude of the vibration of the first mechanical structure 311 is consistent with the amplitude of the vibration of the second mechanical structure 321.

Referring to equation (6), in some embodiments, the magnitudes of the first electrical signal 11 and/or the second electrical signal 12 may be adjusted to obtain the first excitation F ₁ and the second excitation F ₂ with different magnitudes, so that the volume of the first acoustic wave 21 is consistent with the volume of the second acoustic wave 22.

As an example, due to M ₁＞M₂, we can set a power amplifying circuit in the signal processing circuit 330. For example, the power conditioning circuit 335 may be the power amplifying circuit. The power amplification circuit may amplify the first electrical signal 11 such that the power of the first electrical signal 11 is greater than the power of the second electrical signal 12. Thus, if the first electrical signal 11 is the same as the second electrical signal 12 in amplitude without passing through the power conditioning circuit 335, the amplitude of the first electrical signal 11 is greater than the amplitude of the second electrical signal 12 after passing through the power conditioning circuit 335. The first speaker 310 receives the amplified first electrical signal such that the first stimulus F ₁ generated by the first speaker 310 is greater than the second stimulus F ₂ (i.e., F ₁＞F₂) generated by the second speaker 320.

By way of example, due to M ₁＞M₂, we can set a power decay circuit in the signal processing circuit 330. For example, the power conditioning circuit 335 may be the power decay circuit. The power attenuation circuit may attenuate the second electrical signal 12. Thus, the amplitude of the first electrical signal 11 is greater than the amplitude of the second electrical signal 12. The second speaker 320 receives the attenuated second electrical signal 12. Thus, if the first electrical signal 11 and the second electrical signal 12 have the same amplitude without passing through the power adjustment circuit 335, the second excitation F ₂ generated by the second speaker 320 based on the attenuated second electrical signal 12 after passing through the power adjustment circuit 335 is smaller than the first excitation F ₁ (i.e., F ₁＞F₂). In the case of other independent variables, in combination with equation (6), the first stimulus F ₁ is greater than the second stimulus F ₂, which can bring X ₁ into agreement with X ₂. Then, the power of the first sound wave 21 is the same as the power of the second sound wave 22, and the volume of the first sound wave 21 heard by the user is the same as the volume of the second sound wave 22. This corrects for the difference in the sound volume due to the difference in mass (M ₁＞M₂) between the first mechanical structure 311 and the second mechanical structure 321. As an example, the gain of the audio signal of the bone conduction speaker at both sides of the bone conduction earphone can be adjusted by the chip control software in the bone conduction earphone, so that the volume at both sides of the bone conduction earphone is consistent.

Furthermore, in some embodiments, the difference in the volumes of the first acoustic wave 21 and the second acoustic wave 22 caused by the difference in mass may also be corrected directly by adjusting the mass of the first mechanical structure 311 and/or the second mechanical structure 321 such that the mass of the first mechanical structure 311 coincides with the mass of the second mechanical structure 321. For example, a headset microphone, function keys, etc. are provided on one side of the first speaker 310, resulting in a first mechanical structure 311 having a greater mass than the second mechanical structure 321, which may be achieved by adding an additional weight to one side of the second speaker 320, such that the mass of the second mechanical structure 321 is increased to be the same as the mass of the first mechanical structure 311. Thus, the first mechanical structure 311 and the second mechanical structure 321 have the same mass, and finally, the volume of the first sound wave 21 is the same as the volume of the second sound wave 22.

It should be noted that, the volume and the power mentioned in the foregoing schemes and/or embodiments for adjusting the volume are all for the volume and the power of the sound emitted by the speaker on the earphone, and are not the power consumption of the earphone. The above-described arrangements and/or embodiments of adjusting volume are not isolated. The above-described arrangements and/or embodiments of adjusting the volume may be used alone to adjust the volume across the sound output device 300. The volume adjustment schemes and/or embodiments described above may also be combined and used in combination to adjust the volume at both ends of the sound output device 300. For example, the mass adjustment and the excitation adjustment may be performed simultaneously. For example, when M ₁＞M₂, the methods of combining the schemes of "increasing the mass of the second mechanical structure 311", "increasing the first excitation", "increasing the diameter of the first coil", and the like may be used simultaneously to make the volumes of the first speaker 310 and the second speaker 320 uniform.

The above-described solutions and/or embodiments have a good technical result in practical production. As an example, the results of testing three earphone samples are listed below. Sample 1: the bone conduction speaker at one side with small volume uses a coil with thicker wire diameter, and the other side uses a normal coil; sample 2: the bone conduction speaker on one side with high volume uses a coil with a thinner wire diameter, and the other side uses a normal coil; sample 3: the bone conduction speaker at the side with high volume is connected with a resistor with a certain resistance value in series. The same functional module is added on the bone conduction loudspeaker on one side of the three samples, and the functional module is not arranged on the other side of the three samples. And a mobile phone is used for playing white noise signals, earphone samples to be tested are connected through Bluetooth, and the total current of each earphone battery end under the same volume is tested. The test results are shown in Table 1. During the test, the output voltage of the battery terminal is basically unchanged (4.0-4.2V).

Table 1 total current at battery end for earphone samples at the same volume

From the test results in table 1, it can be seen that the total current at the battery terminal of each of the three earphone samples (sample 1, sample 2, sample 3) having the additional function module was increased compared with that of the normal earphone at the same listening volume. Of the three samples, sample 2 (speaker on the side with high volume uses a coil with smaller wire diameter and the other side uses a normal coil) has the smallest total current; sample 1 (speaker with small volume on one side using thicker wire diameter coil and normal coil on the other side) had the greatest total current. The sample 3 (the bone conduction speaker with high volume and a resistor with a certain resistance value is connected in series) is only required to be connected with a resistor in series on the circuit board or the effect of connecting the resistor in series is achieved in other modes, materials are not required to be added in the production and design process, and the influence on the production and design is small.

In addition, the battery life time of the different samples was tested. The test is carried out under the same listening volume (85 dB), white noise signals are played by using the mobile phone, earphone samples to be tested are connected through Bluetooth, batteries with the same capacity are used for different earphone samples, the batteries are in a fully charged state at the beginning of the test, and the actual use time of the different samples is shown in a table 2.

Table 2 earphone sample battery life time

From the test results in table 2, it can be seen that at the same volume of listening, the three sample cells were significantly less long in use than the normal sample, sample 1 was used for the shortest time, and sample 3 was used for a slightly shorter time than sample 2, but the difference was not large. The above results are consistent with the previous battery current test results.

As can be seen from the foregoing description, if the volume of the first sound wave 21 heard by the user is smaller than the volume of the second sound wave 22 heard by the user, the difference in the volumes of the two headphones can be compensated by adjusting the headphone design structure. In addition, for the difference in volume of the earphone, the sound image formed by the earphone can be adjusted.

Sound image refers to the sound-producing location point of a sound source in a sound field, i.e., sound image is the azimuth of sound. For the user, the brain of the user will determine that the sound producing position of the target sound information (i.e., the sound image perceived by the user) is biased to the side of the second sound wave 22 that is louder, i.e., the side of the second speaker 320. While in practice the distance of the first speaker 310 and the second speaker 320 from the user may be considered the same, i.e. the actual sound image of the target sound information 10 is centered (i.e. from directly in front of or directly behind the user). That is, an offset is generated between the sound image perceived by the user and the actual sound image. The application provides a sound image adjusting method, which can enable the sound image perceived by a user to be as close to the actual sound image as possible, so that the deviation of the sound image perceived by the user to the actual sound image is reduced. The sound image adjusting method can be independently applied to the earphone described by the application, and can also be combined with the scheme and/or the embodiment of the volume compensation.

Fig. 9 shows a flowchart of a method S100 for adjusting an acoustic image according to an embodiment of the present application. The process S100 may be used to adjust the sound image output by the first speaker 310 and the second speaker 320 of the sound output apparatus 300. Specifically, the process S100 may include: s110, acquiring the volume difference of the first sound wave and the second sound wave; s120, adjusting the time difference between the first sound wave and the second sound wave.

"Binaural effects" are effects in which one relies on differences in volume, time, phase and tone between ears to determine the orientation of sound. Because of a certain distance between the left ear and the right ear, the volume, time, phase and tone of the same sound transmitted from other directions to the two ears are sequential except the sound from the right front and the right rear, thereby generating a sound difference, a time difference, a phase difference and a tone difference. As an example, if the sound source is right-hand, the sound must reach the right ear before the left ear. The more the sound is to one side, the larger the time difference. As an example, if the sound source is right-hand, the sound source is closer to the right ear than the left ear, and the volume reaching the right ear is greater than the left ear. The more the sound is to one side, the larger the difference in the sound volume. As an example, sound is propagated in the form of waves, while the phase of sound waves at spatially different locations is different. Due to the spatial distance between the ears, the phase of the sound waves reaching the ears may differ. The tympanic membrane within the eardrum vibrates with the sound waves. The phase difference of the vibration also becomes a factor in discriminating the sound source orientation by the user's brain.

The human brain relies on the "binaural effect" to determine the position of the sound source (i.e. the sound image).

If the left ear hears the sound first, the listener's brain perceives the sound as coming from the left (the side where the sound was first heard), i.e., the listener's brain perceives the sound image as being biased to the left. And vice versa. This phenomenon is known as the "time difference effect" between the left and right ears.

If the left ear hears more sound than the right ear, the listener's brain will consider the sound coming from the left direction and vice versa. This phenomenon is known as the "volume difference effect" between the left and right ears. The aforementioned sound image shift due to the difference between the first mechanical structure mass and the second mechanical structure mass can also be essentially understood as "volume difference effect".

Thus, we can use the "time difference" and/or the "phase difference" to adjust the shift of the user perceived sound image due to the "sound difference".

S110, acquiring the sound difference of the first sound wave and the second sound wave. First, we obtain the difference in volume of the first sound wave 21 and the second sound wave 22. From the difference in volume, a value of the sound image offset due to the difference in volume can be obtained. For example, the volume of the first sound wave 21 is smaller than the volume of the second sound wave 22 by β, and the sound image perceived by the user is shifted from the centered position by δ toward the second speaker 320.

S120, adjusting the pronunciation time difference of the first sound wave and the second sound wave.

In some embodiments, the shift in the user perceived sound image due to the difference in mass of the first mechanical structure 311 and the second mechanical structure may be adjusted by adjusting the time difference in the sound production of the first sound wave 21 and the second sound wave 22.

Taking the example that the volume of the first sound wave 21 is smaller than the volume of the second sound wave 22. The first time period t ₁ is required for the sound output device 300 to convert the target sound information 10 into the first sound wave 21; the second time period t ₂ is required for the sound output device 300 to convert the target sound information 10 into the second sound wave 22; and the first time length t ₁ is shorter than the second time length t ₂. Thus, the sound emission time of the first speaker 310 is earlier than the sound emission time of the second speaker 320 for the target sound information 10. In some embodiments, the articulation time of the first speaker 310 is advanced by a time difference from the articulation time of the second speaker 320. In some embodiments, the time difference is not greater than 3ms. Specifically, the time difference may be any one of the following values or any value ：0.1ms,0.2ms,0.3ms,0.4ms,0.5ms,0.6ms,0.7ms,0.8ms,0.9ms,1.0ms,1.1ms,1.2ms,1.3ms,1.4ms,1.5ms,1.6ms,1.7ms,1.8ms,1.9ms,2.0ms,2.1ms,2.2ms,2.3ms,2.4ms,2.5ms,2.6ms,2.7ms,2.8ms,2.9ms,3.0ms. between any two values, assuming that the first acoustic wave 21 and the second acoustic wave 22 are identical in information other than the sound emission time. In the case where the transmission medium and the transmission distance are the same, the first acoustic wave 21 heard by the user's left ear will be longer than the second acoustic wave 22 heard by the right ear. Based on the binaural effect, the user's brain will determine that the source location of the target sound information 10 is biased to one side of the earlier-pronounced first sound wave 21, i.e., the left side of the user. Thus, considering the right shift of the sound image caused by the volume of the first sound wave 21 being smaller than the volume of the second sound wave 22, the source position of the target sound information 10 heard by the end user (i.e., the sound image perceived by the user) is also adjusted to the intermediate position. This solves the problem of right shift of the sound image due to the mass of the first mechanical structure 311 being greater than the mass of the second mechanical structure 321.

In some embodiments, the sound image position of the headphones may be adjusted by controlling the time difference of the audio signals of the speakers on both sides (i.e., the time difference of the left and right channels of the audio signals). For example, the sound image position of the earphone can be adjusted by controlling the time difference of sound waves output from the speakers on both sides. For example, the first sound wave output by the first speaker is made earlier than the second sound wave output by the second speaker by the action of the first speaker and the action of the second speaker. In some embodiments, the first sound wave is advanced by a time difference from the second sound wave. In some embodiments, the time difference is not greater than 3ms. Specifically, the time difference may be any value of or any value ：0.1ms,0.2ms,0.3ms,0.4ms,0.5ms,0.6ms,0.7ms,0.8ms,0.9ms,1.0ms,1.1ms,1.2ms,1.3ms,1.4ms,1.5ms,1.6ms,1.7ms,1.8ms,1.9ms,2.0ms,2.1ms,2.2ms,2.3ms,2.4ms,2.5ms,2.6ms,2.7ms,2.8ms,2.9ms,3.0ms. between any two values, for example, the time difference may be 1.0ms or a value slightly greater than 1.0 ms.

In some embodiments, the sound image position of the headphones may be adjusted by controlling the time difference of the audio signals input to the speakers on both sides (i.e., the time difference of the first electrical signal and the second electrical signal). For example, the first electrical signal input to the first speaker is advanced relative to the second electrical signal input to the second speaker by the action of the signal processing circuit. In some embodiments, the first electrical signal is advanced by a time difference from the second electrical signal. In some embodiments, the time difference is not greater than 3ms. Specifically, the time difference may be any value of or any value ：0.1ms,0.2ms,0.3ms,0.4ms,0.5ms,0.6ms,0.7ms,0.8ms,0.9ms,1.0ms,1.1ms,1.2ms,1.3ms,1.4ms,1.5ms,1.6ms,1.7ms,1.8ms,1.9ms,2.0ms,2.1ms,2.2ms,2.3ms,2.4ms,2.5ms,2.6ms,2.7ms,2.8ms,2.9ms,3.0ms. between any two values, for example, the time difference may be 1.0ms or a value slightly greater than 1.0 ms.

Further, the offset value δ of the user-perceived sound image is obtained, and the user-perceived sound image can also be adjusted by adjusting the phase difference of the first sound wave 21 and the second sound wave 22 so as to center the user-perceived sound image. As an example, it is assumed that the phase of the first acoustic wave 21 needs to be larger than the phase of the second acoustic wave 22 by δw ₂ to shift the sound image by δ toward the direction of the first acoustic wave 21.

In order to make the phase of the first sound wave 21 larger than the phase of the second sound wave 22 δw ₂, a phase delay circuit may be provided in the signal processing circuit 330 and/or the first speaker 310 and/or the second speaker 320.

For example, the phase delay circuit may be provided in the second speaker 320 so that the phase of the first acoustic wave 21 is δw ₂ larger than the phase of the second acoustic wave 22. For example, the signal processing circuit 330 processes the target sound information 10 so that the generated first electric signal 11 and the generated second electric signal 12 have the same phase. The second speaker 320 may have a phase delay circuit disposed therein. The second speaker 320 may delay the phase of the second electrical signal 12 by δw ₂ and generate the second acoustic wave 22 with the same phase delay δw ₂. That is, the phase of the final first acoustic wave 21 is δw ₂ greater than the phase of the second acoustic wave 22. The user perceived sound image is shifted in the direction of the first sound wave 21 with a larger phase according to the binaural effect. In this way, the shift of the sound image in the direction of the second sound wave 22 due to the mass m ₁ of the first mechanical structure 311 being greater than the mass m ₂ of the second mechanical structure 321 can be counteracted. Eventually, the user perceived sound image is centered.

For example, the phase delay circuit may be provided in the signal processing circuit 330 so that the phase of the first acoustic wave 21 is larger than the phase of the second acoustic wave 22 by δw ₂. For example, the signal processing circuit 330 may process the target sound information 10 to obtain the first electric signal 11 and the second electric signal 12. The phase of the first electrical signal 11 is greater than the phase of the second electrical signal 12 by δw ₁. And δw ₁＝δw₂. The first speaker 310 performs the same phase processing on the first electrical signal 11 and the second speaker 320 performs the same phase processing on the second electrical signal 12 (e.g., the first speaker 310 does not process the phase of the first electrical signal 11; the second speaker 320 does not process the phase of the second electrical signal 12). Thus, the phase of the first sound wave 21 generated by the first speaker 310 is finally larger than the phase of the second sound wave 22 generated by the second speaker 320 by δw ₂. The user perceived sound image is shifted in the direction of the first sound wave 21 with a larger phase according to the binaural effect. In this way, the shift of the sound image in the direction of the second sound wave 22 due to the mass m ₁ of the first mechanical structure 311 being greater than the mass m ₂ of the second mechanical structure 321 can be counteracted. Eventually, the user perceived sound image is centered.

In some embodiments, the difference in volume of the first sound wave and the second sound wave is no greater than 3dB. In this way, the "time difference" and/or the "phase difference" are used to adjust the offset of the user perceived sound image due to the "sound difference", on the one hand, the user perceived sound image is adjusted, and on the other hand, the hearing of the user is not affected. This is because, by adjusting the phase/time difference so that the sound image is centered, only the sound image perceived by the user is adjusted, and the volumes of the first sound wave and the second sound wave actually heard by the left and right ears are not changed. If the volume difference of sound waves heard by the left ear and the right ear is too large, the ears of a listener can be damaged after long-term use.

In summary, the present application provides a sound image adjusting method S100 and a volume adjusting method S200. The sound image adjusting method S100 of the present application includes: s110, acquiring the volume difference of the first sound wave and the second sound wave; s120, adjusting the pronunciation time difference of the first sound wave and the second sound wave. The volume adjustment method S200 of the present application includes: s210, acquiring the volume difference of the first sound wave and the second sound wave; and S220, adjusting the amplitude difference of the first excitation and the second excitation. According to the sound image adjusting method S100, the time difference between the first sound wave and the second sound wave is set, so that the deviation of the sound image perceived by the user due to the quality difference of the first mechanical structure and the second mechanical structure is corrected. According to the volume adjusting method S200, volume difference between the first loudspeaker and the second loudspeaker caused by mass difference of the first mechanical structure and the second mechanical structure is corrected by setting different coil resistivity, coil winding diameter, magnetic field strength and/or resistance.

From the foregoing description, it is apparent that: and the volume of sound waves generated by the speaker is positively correlated with the amplitude of mechanical structures in the speaker, irrespective of the difference in transmission medium and transmission distance. The larger the amplitude of the mechanical structure, the greater the volume of the sound wave. And the amplitude of the mechanical structure is positively correlated with the excitation to which the mechanical structure is subjected. For the same mechanical structure, the greater the excitation the mechanical structure receives, the greater the amplitude of the mechanical structure.

In some embodiments, the volume of the first sound wave generated by the first mechanical structure and the volume of the second sound wave generated by the second mechanical structure in the sound output device may be different under the same excitation. For example, in the sound output apparatus 300 shown in fig. 1, the additional device 940 is configured to cause the mass of the first mechanical structure 311 to be greater than the mass of the second mechanical structure 321 (i.e., M ₁＞M₂). Referring to equation (6), at the same excitation f, the amplitude of the first mechanical structure vibration is smaller than the amplitude of the second mechanical structure vibration. Regardless of the difference in transmission medium and transmission distance, the user perceives the first sound wave to have a volume less than the second sound wave. Of course, in some embodiments, the reason for the difference in volume of the sound waves output from the two ends of the sound output device may be other reasons, for example, a common earphone without a headset microphone may have a difference in quality of the two ends due to water intake or other reasons, and finally, the difference in volume of the sound emitted from the two ends of the earphone may also be caused. For ease of understanding, in the following description we will take bone conduction speakers as an example.

In practice, in order not to affect the user experience, we need to make the volume of the sound heard by both ears of the user as uniform as possible. From the foregoing description, it is understood that the volume of sound waves generated by a speaker in a sound output device is related to excitation generated based on an electric signal, mass M of a mechanical structure that generates vibration, damping C and rigidity K of a vibration system, and the like.

For example, taking bone conduction speaker 100 as an example, according to equation (6), the volume of sound waves generated by bone conduction speaker 100 is simultaneously affected by the following parameters: the frequency of excitation F (equal to 1/ω), the amplitude F ₀ of excitation F, the mass m ₁ of the housing 120, the mass m ₂ of the magnetic circuit 130, the stiffness k ₁ and the damping c ₁ of the vibration-transmitting plate 140, and the stiffness k ₂ and the damping c ₂ of the ear-hook 110. For example, the amplitude F ₀ of the excitation F is proportional to the vibration amplitude X ₁ of the housing 120, while keeping the other parameters unchanged. The greater the amplitude F ₀ of the excitation F, the greater the amplitude X ₁ of the housing 120. For another example, the larger the mass m ₁ of the housing 120 of the bone conduction speaker 100, the smaller the amplitude X ₁ of the housing 120, while keeping other parameters unchanged. Therefore, when the above parameters are changed, the amplitude X ₁ of the housing 120 is also changed. The amplitude X ₁ of the housing 120 is positively correlated with the volume of sound waves generated by vibration of the housing 120 regardless of the difference in transmission medium and transmission distance. The larger the amplitude X ₁, the greater the volume of the sound wave; the smaller the amplitude X ₁, the smaller the volume of the sound wave.

Thus, if the excitation F and the mass M of the mechanical structure can be reasonably balanced, a desired vibration amplitude X can be obtained. Even if there is a difference in the mechanical structure quality of both ends of the sound output device (for example, the ear microphone is arranged on one side of the bone conduction earphone), the volume output by both ends of the sound output device can be consistent.

Therefore, the application also provides a sound output device. The sound output device may include, but is not limited to, headphones, hearing aids, helmets, and the like. The headset may include, but is not limited to, a wired headset, a wireless headset, a bluetooth headset, and the like. Specifically, the sound output device may include a first speaker, a second speaker, and a signal processing circuit.

The signal processing circuit may receive target sound information, process the target sound information, and generate a first electrical signal and a second electrical signal.

The first speaker is electrically connected with the signal processing circuit. The first speaker may receive a first electrical signal from the signal processing circuit and convert the first electrical signal into a first sound wave. In some embodiments, the first speaker comprises a first bone conduction speaker and the first sound wave comprises a first bone conduction sound wave. In some embodiments, the first speaker may convert the received first electrical signal into mechanical vibrations. Further, the first sound wave is generated by the mechanical vibration. In some embodiments, the first speaker may include a first mechanical structure and a first excitation device. The first excitation device generates a first excitation based on the first electrical signal. The first excitation excites the first mechanical structure vibration as an external force, and further, the first mechanical structure vibration generates a first sound wave.

The second speaker is electrically connected with the signal processing circuit. The second speaker may receive a second electrical signal from the signal processing circuit and convert the second electrical signal to a second acoustic wave. In some embodiments, the second speaker comprises a second bone conduction speaker and the second sound wave comprises a second bone conduction sound wave. In some embodiments, the second speaker may convert the received second electrical signal into mechanical vibration. Further, the second sound wave is generated by the mechanical vibration. In some embodiments, the second speaker may include a second mechanical structure and a second excitation device. The second excitation device generates a second excitation based on the second electrical signal. The second excitation excites the second mechanical structure vibration as an external force, and further, the second mechanical structure vibration generates a second sound wave.

In some embodiments, the first excitation device and the second excitation device may be electromagnetic excitation devices. The magnitude of the first stimulus and the magnitude of the second stimulus can be calculated by formula (1); the vibration process of the first mechanical structure and the second mechanical structure can be expressed by formula (6).

For convenience of description, in the following description of the present application, the magnitude of the first excitation is represented by F ₁, the magnitude of the second excitation is represented by F ₂, the mass of the first mechanical structure is represented by M ₁, the mass of the second mechanical structure is represented by M ₂, the sectional area of the first coil winding is represented by S ₁, the sectional area of the second coil winding is represented by S ₂, the resistivity of the first coil winding is represented by ρ ₁, the resistivity of the second coil winding is represented by ρ ₂, the magnetic field strength of the first magnetic member is represented by B ₁, the magnetic field strength of the second magnetic member is represented by B ₂, the resistance of the first coil winding (hereinafter referred to as first resistance) is represented by R ₁, the resistance of the second coil winding (hereinafter referred to as second resistance) is represented by R ₂, the amplitude of the first mechanical structure vibration is represented by X ₁, and the amplitude of the second mechanical structure vibration is represented by X ₂.

For the same excitation, the first mechanical structure produces a lower volume than the second mechanical structure. As an example, in some embodiments, the mass M ₁ of the first mechanical structure is greater than the mass M ₂ of the second mechanical structure, resulting in a volume of the first sound wave generated by the first mechanical structure vibrating less than a volume of the second sound wave generated by the second mechanical structure vibrating under the same excitation. Referring to equations (1) and (6), we assume that the first and second electrical signals are identical (U ₁＝U₂) and that the first and second excitation devices are identical (i.e., B ₁＝B₂,S₁＝S₂,ρ₁＝ρ₂,R₁＝R₂), irrespective of differences in damping and stiffness (i.e., C ₁＝C₂,K₁＝K₂), then, according to equations (1) and (6), the first and second excitations F ₁ and F ₂ can be derived to be identical (F ₁＝F₂). Based on the above assumption, due to M ₁＞M₂, the amplitude of the first mechanical structure vibration is smaller than the amplitude of the second mechanical structure vibration as seen from the relation of the mass and the amplitude. In the case where the propagation medium and the propagation distance are the same, the volume of the sound wave emitted by the first speaker heard by the user will be smaller than the volume of the sound wave emitted by the second speaker.

The volume of the first sound wave is the same as the volume of the second sound wave.

For ease of description, we will take the example of the user's left ear hearing the first sound wave and the right ear hearing the second sound wave. In general, it is desirable that the volume of the first sound wave heard by the left ear of the user is as same as the volume of the second sound wave heard by the right ear as possible to avoid damage to both ears due to the difference in volume. That is, in the case where the transmission distance and the transmission medium are the same, it is desirable that the amplitude of the vibration of the first mechanical structure is as uniform as possible with the amplitude of the vibration of the second mechanical structure.

In some embodiments, the diameter of the first coil wire is greater than the diameter of the second coil wire, i.e., S ₁＞S₂. According to equations (1) and (6), the first excitation F ₁ generated by the first excitation device is greater than the second excitation F ₂ generated by the second excitation device, such that X ₁ is consistent with X ₂. Then, the power of the first sound wave is the same as the power of the second sound wave, and the volume of the first sound wave heard by the user is the same as the volume of the second sound wave. This corrects for the difference in the sound volume due to the difference in mass (M ₁＞M₂) between the first and second mechanical structures.

In some embodiments, the resistivity of the first coil is less than the resistivity of the second coil, i.e., ρ ₁＜ρ₂. According to equations (1) and (6), X ₁ can be made consistent with X ₂ by the first excitation device producing a first excitation F ₁ that is greater than the second excitation device producing a second excitation F ₂. Then, the power of the first sound wave is the same as the power of the second sound wave, and the volume of the first sound heard by the user is the same as the volume of the second sound wave. This corrects for the difference in sound volume due to the difference in mass of the first mechanical structure and the second mechanical structure.

In some embodiments, the magnetic field strength B ₁ generated by the first electromagnetic excitation device is greater than the magnetic field strength B ₂ generated by the second electromagnetic excitation device at the same input current. According to equations (1) and (6), the second excitation F ₁ generated by the first excitation device is greater than the second excitation F ₂ generated by the second excitation device, such that X ₁ is consistent with X ₂. Then, the power of the first sound wave is the same as the power of the second sound wave, and the volume of the first sound wave heard by the user is the same as the volume of the second sound wave. This corrects for the difference in sound volume due to the difference in mass of the first mechanical structure and the second mechanical structure. In some embodiments, the remanence of the first magnetic member is greater than the remanence of the second magnetic member such that the magnetic field strength B ₁ generated by the first electromagnetic excitation device is greater than the magnetic field strength B ₂ generated by the second electromagnetic excitation device. In some embodiments, the coercivity of the first magnetic element is greater than the coercivity of the second magnetic element such that the magnetic field strength B ₁ generated by the first electromagnetic actuation device is greater than the magnetic field strength B ₂ generated by the second electromagnetic actuation device. In some embodiments, the magnetic energy product of the first magnetic member is greater than the magnetic energy product of the second magnetic member such that the magnetic field strength B ₁ generated by the first electromagnetic excitation device is greater than the magnetic field strength B ₂ generated by the second electromagnetic excitation device.

In some embodiments, the first resistance R ₁ is less than the second resistance R ₂. According to equations (1) and (6), X ₁ can be made consistent with X ₂ by the first excitation device producing a first excitation F ₁ that is greater than the second excitation device producing a second excitation F ₂. Then, the power of the first sound wave is the same as the power of the second sound wave, and the volume of the first sound wave heard by the user is the same as the volume of the second sound wave. This corrects for the difference in sound volume due to the difference in mass of the first mechanical structure and the second mechanical structure.

In some embodiments, the difference in the sound volume due to the difference in the mass of the first mechanical structure and the second mechanical structure may be corrected by connecting a resistor in series outside the second coil such that the first resistor R ₁ is smaller than the second resistor R ₂.

In some embodiments, the difference in sound volume due to the difference in mass of the first and second mechanical structures may be corrected by decreasing the resistance R ₁ of the first coil and/or increasing the resistance R ₂ of the second coil such that the first resistance R ₁ is less than the second resistance R ₂.

According to the formula r=ρl/S, in some embodiments, the resistance of the first coil may be made smaller than the resistance of the second coil by increasing the resistivity of the first coil and/or decreasing the resistivity of the second coil.

According to the formula r=ρl/S, in some embodiments, the resistance of the first coil may be made smaller than the resistance of the second coil by increasing the length of the windings of the first coil and/or decreasing the length of the windings of the second coil.

According to the formula r=ρl/S, in some embodiments, the resistance of the first coil may be made smaller than the resistance of the second coil by decreasing the diameter of the windings of the first coil and/or increasing the diameter of the windings of the second coil.

The first coil and/or the second coil may also change in mass when the resistivity, the winding length, and/or the winding diameter of the first coil and/or the second coil are increased and/or decreased. The mass of the coil will also have an effect on the vibrations of the first mechanical structure. Therefore, when adjusting parameters such as resistivity, winding length and/or winding diameter, it is also necessary to consider the influence of other parameters, so that the amplitude of the vibration of the final first mechanical structure is consistent with that of the vibration of the second mechanical structure.

In some embodiments, a power amplification circuit may be provided in the sound output device. The power amplification circuit may be disposed between the first speaker and the signal processing circuit. The first electric signal output by the signal processing circuit passes through the power amplifying circuit. The power amplification circuit amplifies the first electrical signal and outputs the first electrical signal to the first speaker. The first speaker receives the amplified first electrical signal. Thus, the first excitation F ₁ generated by the first speaker is greater than the second excitation F ₂ (i.e., F ₁＞F₂) generated by the second speaker. In conjunction with equation (6), the first stimulus F ₁ is greater than the second stimulus F ₂, which can bring X ₁ into agreement with X ₂. Then, the power of the first sound wave is the same as the power of the second sound wave, and the volume of the first sound wave heard by the user is the same as the volume of the second sound wave. This corrects for the difference in sound volume due to the difference in mass of the first mechanical structure and the second mechanical structure.

In some embodiments, a power attenuation circuit may be provided in the sound output device. The power attenuation circuit may be disposed between the second speaker and the signal processing circuit. The second electric signal output by the signal processing circuit passes through the power attenuation circuit. The power attenuation circuit attenuates the second electric signal and outputs the second electric signal to the second speaker. The second speaker receives the attenuated second electrical signal. Thus, the second excitation F ₂ generated by the second speaker is less than the first excitation F ₁ (i.e., F ₁＞F₂) generated by the first speaker. In conjunction with equation (6), the first stimulus F ₁ is greater than the second stimulus F ₂, which can bring X ₁ into agreement with X ₂. Then, the power of the first sound wave is the same as the power of the second sound wave, and the volume of the first sound wave heard by the user is the same as the volume of the second sound wave. This corrects for the difference in sound volume due to the difference in mass of the first mechanical structure and the second mechanical structure.

According to the foregoing description, when a difference in sound volume occurs at both ends of the earphone, the sound image perceived by the user may deviate. Therefore, it is necessary to design the sound output device reasonably so that the sound image output from the sound output device is not shifted as much as possible.

And under the input of electric signals with the same amplitude and frequency, the volume of the sound wave output by the first loudspeaker is smaller than that of the sound wave output by the second loudspeaker. As an example, in some embodiments, the mass M ₁ of the first mechanical structure is greater than the mass M ₂ of the second mechanical structure, resulting in a volume of sound waves output by the first speaker that is less than a volume of sound waves output by the second speaker at the same amplitude and frequency of electrical signal input. Referring to equations (1) and (6), we assume that the first and second electrical signals are identical in amplitude and frequency (i.e., U ₁＝U₂), and that the first and second excitation devices are identical (i.e., B ₁＝B₂,S₁＝S₂,ρ₁＝ρ₂,R₁＝R₂), irrespective of differences in damping and stiffness (i.e., C ₁＝C₂,K₁＝K₂), then, according to equations 1) and (6), the first and second excitations F ₁ and F ₂ can be derived to be identical (F ₁＝F₂). Based on the above assumption, due to M ₁＞M₂, the amplitude of the first mechanical structure vibration is smaller than the amplitude of the second mechanical structure vibration as seen from the relation of the mass and the amplitude. In the case where the propagation medium and the propagation distance are the same, the volume of the sound wave emitted by the first speaker heard by the user will be smaller than the volume of the sound wave emitted by the second speaker. As an example, the difference between the volume of the first sound wave and the volume of the second sound wave is not more than 3dB under the input of the electric signals of the same amplitude and frequency.

For convenience of explanation, in the following description of the present application, the perception of target sound information by a user will be described taking as an example that a first sound wave is transmitted to the left ear of the user and a second sound wave is transmitted to the right ear of the user. Assuming that the first sound wave and the second sound wave are identical in information except for the sound volume, the sound volume of the first sound wave heard by the left ear of the user is smaller than the sound volume of the second sound wave heard by the right ear of the user according to the binaural effect, the brain of the user determines that the sound producing position of the target sound information (i.e., the sound image perceived by the user) is biased to the right side, i.e., the side of the second sound wave having a larger sound volume.

Depending on the binaural effect, the "phase difference" and/or the "time difference" may be utilized to account for the sound image shift due to the "sound difference".

In some embodiments, the sound output device 300 requires a first time period t ₁ to convert the target sound information 10 into the first sound wave 21, and a second time period t ₂ to convert the target sound information 10 into the second sound wave 22, the first time period t ₁ being shorter than the second time period t ₂ by a time difference δt. Thus, the sound emission time of the first speaker 310 is advanced by the time difference δt from the sound emission time of the second speaker 320 for the target sound information 10. In some embodiments, the time difference δt is not greater than 3ms. Specifically, the time difference δt may be any value of the following values or any value ：0.1ms,0.2ms,0.3ms,0.4ms,0.5ms,0.6ms,0.7ms,0.8ms,0.9ms,1.0ms,1.1ms,1.2ms,1.3ms,1.4ms,1.5ms,1.6ms,1.7ms,1.8ms,1.9ms,2.0ms,2.1ms,2.2ms,2.3ms,2.4ms,2.5ms,2.6ms,2.7ms,2.8ms,2.9ms,3.0ms. between any two values, for example, the time difference δt may be 1.0ms or a value slightly greater than 1.0 ms. It is assumed that the first acoustic wave 21 and the second acoustic wave 22 are identical in information other than the sound emission time. In the case where the transmission medium and the transmission distance are the same, the first acoustic wave 21 heard by the user's left ear will be longer than the second acoustic wave 22 heard by the right ear. The source location (i.e., the user perceived sound image) of the target sound information 10 heard by the user is corrected based on the binaural effect.

In some embodiments, the time difference occurs during the first speaker converting the first electrical signal into the first sound wave and the second speaker converting the second electrical signal into the second sound wave. For example, a time advance circuit may be provided in the first speaker and/or a time delay circuit may be provided in the second speaker such that the first sound wave output by the first speaker is advanced relative to the second sound wave output by the second speaker. In some embodiments, the first sound wave is advanced by a time difference δt from the second sound wave.

In some embodiments, the time difference occurs during the conversion of the target sound information into the first electrical signal and the second electrical signal by the sound output device. For example, the time processing circuit may be provided in the signal processing circuit such that the first electrical signal input to the first speaker is advanced relative to the second electrical signal input to the second speaker. In some embodiments, the first electrical signal is advanced by a time difference δt from the second electrical signal.

In some embodiments, a first phase difference δw ₁ exists between the second sound wave and the first sound wave. In some embodiments, the phase of the first acoustic wave is δw ₁ greater than the phase of the second acoustic wave. Assuming that the first sound wave and the second sound wave are identical in information except for the phase, the brain of the user determines that the location of the source of the target sound information (i.e., the sound image perceived by the user) is biased to one side of the first sound wave with a larger phase, i.e., the left side of the user, based on the binaural effect. Thus, considering the right shift of the sound image caused by the volume of the first sound wave being smaller than the volume of the second sound wave, the source position of the target sound information heard by the user is finally adjusted to the middle position. This solves the problem of the shift of the sound image due to the mass of the first mechanical structure being greater than the mass of the second mechanical structure.

In some embodiments, the second electrical signal is the same phase as the first electrical signal. As an example, the signal processing circuit may process the target sound information so that the generated first electric signal and the second electric signal are identical in phase. Further, a phase delay circuit may be provided in the second speaker. The phase delay circuit may delay the phase of the second electrical signal by δw ₁ and generate a second acoustic wave having a phase that is likewise delayed by δw ₁. Thus, the phase of the first sound wave can be made larger than the phase of the second sound wave by δw ₁. In this way, the sound-image shift due to the mass of the first mechanical structure being greater than the mass of the second mechanical structure can be solved.

In some embodiments, there is a second phase difference δw ₂ between the second electrical signal and the first electrical signal; and the second phase difference δw ₂ is the same as the first phase difference δw ₁. As an example, a phase delay circuit may be provided in the signal processing circuit. The signal processing circuit may process the target sound information to obtain the first electrical signal and the second electrical signal. And, there is a second phase difference δw ₂ between the first electrical signal and the second electrical signal. For example, the phase of the first electrical signal is δw ₂ greater than the phase of the second electrical signal. The first speaker and the second speaker do not change the phase of the first electrical signal and the phase of the second electrical signal, such that the first sound wave generated by the first speaker is δw ₂ greater than the phase of the second sound wave generated by the second speaker. And δw ₂ is the same as δw ₁, that is, eventually, the phase of the first sound wave is δw ₁ greater than the phase of the second sound wave. This also solves the problem of an acoustic image shift due to the mass of the first mechanical structure being greater than the mass of the second mechanical structure.

Thus, the sound emission time of the first speaker is earlier than the sound emission time of the second speaker for the target sound information. It is assumed that the first sound wave and the second sound wave are identical in information other than the sound emission time. In the case where the transmission medium and the transmission distance are the same, the first sound wave is heard by the user's left ear for a longer period of time than the second sound wave is heard by the user's right ear. Based on the binaural effect, the user's brain will determine that the source location of the target sound information is biased to one side of the earlier-pronounced first sound wave, i.e., to the left of the user. Thus, considering the right shift of the sound image caused by the fact that the volume of the first sound wave is smaller than that of the second sound wave, the source position of the target sound information heard by the end user (i.e. the sound image perceived by the user) is also adjusted to the middle position. This solves the problem of a shift in the sound image to the right due to the mass of the first mechanical structure being greater than the mass of the second mechanical structure.

In summary, the present application provides a sound image adjusting method S100, a sound volume adjusting method S200, and two sound output devices. The sound image adjusting method S100 of the present application includes: s110, acquiring the volume difference of the first sound wave and the second sound wave; s120, adjusting the pronunciation time difference of the first sound wave and the second sound wave. The volume adjustment method S200 of the present application includes: s210, acquiring the volume difference of the first sound wave and the second sound wave; and S220, adjusting the amplitude difference of the first excitation and the second excitation. The sound output apparatus and the sound image adjusting method S100 of the present application correct the deviation of the sound image perceived by the user due to the difference in mass of the first mechanical structure and the second mechanical structure by setting the time difference between the first sound wave and the second sound wave. According to the sound output device and the volume adjusting method, volume difference between the first loudspeaker and the second loudspeaker caused by mass difference of the first mechanical structure and the second mechanical structure is corrected by setting different coil resistivity, coil winding diameter, magnetic field strength and/or resistance.

The first and/or second acoustic propagation medium according to the present application does not limit the scope of the present application. The first and/or second sound waves of the present application may propagate through a solid body (e.g., bone) and the first and/or second sound waves may also propagate through a gas (e.g., air). In some embodiments, the propagation medium may comprise one or a combination of air and bone.

It should be noted that, in practical design and production, the volume adjusting method, the sound image adjusting method and the sound output device of the present application may be used in combination, so as to achieve the desired adjusting effect. For example, in some embodiments, the sound image output by the sound output apparatus may be adjusted using the sound image adjusting method S100 alone. For example, in some embodiments, the sound image and the sound volume of the sound output by the sound output device may be adjusted using the sound volume adjustment method S200 and the sound image adjustment method S100 at the same time.

For example, the mass adjustment and the excitation adjustment may be performed simultaneously. For example, when M ₁＞M₂, the methods of "increasing the mass of the second mechanical structure 311", "increasing the first excitation", "increasing the diameter of the first coil", and the like may be used simultaneously to make the sound volumes of the first speaker 310 and the second speaker 320 uniform.

For example, when M ₁＞M₂, the methods of "increasing the mass of the second mechanical structure 311", "increasing the first excitation", "decreasing the diameter of the second coil", and the like may be used simultaneously to keep the volume difference of the first speaker 310 and the second speaker 320 within the target volume difference range; then, the method of setting the phase difference can be adopted at the same time to adjust the sound image.

It should be noted that, the volume of the first speaker and the volume of the second speaker are kept "consistent" or "same" in the present application, which is merely for analysis, and does not limit the scope of protection of the present application. The volume of the first speaker and the volume of the second speaker may be kept identical or the same, and the volume difference between the first speaker and the second speaker may be kept within the target volume difference range.

It should be noted that the "centering" of the sound image of the sound output device according to the present application is also only for analysis, and does not limit the scope of the present application. The centering of the sound image may be maintaining the sound image within a target location range.

In view of the foregoing, it will be evident to a person skilled in the art that the foregoing detailed disclosure may be presented by way of example only and may not be limiting. Although not explicitly described herein, those skilled in the art will appreciate that the present application is intended to embrace a variety of reasonable alterations, improvements and modifications to the embodiments. Such alterations, improvements, and modifications are intended to be proposed by this disclosure, and are intended to be within the spirit and scope of the exemplary embodiments of this disclosure.

The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting. For example, as used herein, the singular forms "a", "an", "the" and "the" include plural referents unless the context clearly dictates otherwise. The terms "comprises," "comprising," and/or "includes" when used in this specification, are taken to specify the presence of stated integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. The term "a on B" as used in this specification means that a is directly adjacent (above or below) B, or that a is indirectly adjacent (i.e., a and B are separated by some material); the term "A within B" means that A is entirely within B, or that part A is within B.

Furthermore, certain terms in the present disclosure have been used to describe embodiments of the present disclosure. For example, "one embodiment," "an embodiment," and/or "some embodiments" means that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the disclosure. Thus, it is emphasized and should be appreciated that two or more references to "an embodiment" or "one embodiment" or "an alternative embodiment" in various portions of this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined as suitable in one or more embodiments of the disclosure.

It should be appreciated that in the foregoing description of embodiments of the disclosure, various features of the application are sometimes grouped together in a single embodiment, figure, or description thereof for the purpose of streamlining the disclosure. Or the application may be varied and features dispersed throughout a plurality of embodiments of the application. However, this is not to say that a combination of these features is necessary, and it is entirely possible for a person skilled in the art to extract some of them as separate embodiments to understand them when reading this application. That is, embodiments of the present application may also be understood as an integration of multiple secondary embodiments. While each secondary embodiment is satisfied by less than all of the features of a single foregoing disclosed embodiment.

In some embodiments, numbers expressing quantities or properties used to describe and claim certain embodiments of the application are to be understood as being modified in some instances by the term "about", "approximately" or "substantially". For example, unless otherwise indicated, "about", "approximately" or "substantially" may mean a 20% change in the value it describes. Accordingly, in some embodiments, the numerical parameters set forth in the written description and attached claims are approximations that may vary depending upon the desired properties sought to be obtained by the particular embodiment. In some embodiments, numerical parameters should be construed in light of the number of reported significant digits and by applying ordinary rounding techniques. Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the embodiments of the application are approximations, the numerical values set forth in the specific examples are reported as precisely as possible.

Each patent, patent application, publication of patent application, and other materials, such as articles, books, specifications, publications, documents, articles, etc., cited herein are hereby incorporated by reference. The entire contents for all purposes, except for any prosecution file history associated therewith, may be any identical prosecution file history inconsistent or conflicting with this file, or any identical prosecution file history which may have a limiting influence on the broadest scope of the claims. Now or later in association with this document. For example, if there is any inconsistency or conflict between the description, definition, and/or use of a term associated with any of the incorporated materials, the term in the present document shall control.

Finally, it is to be understood that the embodiments of the application disclosed herein are illustrative of the principles of embodiments of the present application. Other modified embodiments are also within the scope of the application. Accordingly, the disclosed embodiments are illustrative only and not limiting. Those skilled in the art can adopt alternative configurations to implement the application according to embodiments of the application. Accordingly, embodiments of the application are not limited to those precisely described in the application.

Claims

1. A sound output device for use with headphones, comprising:

A signal processing circuit that generates a first electrical signal and a second electrical signal based on the target sound information at a run time;

A first speaker corresponding to a first ear of a user and electrically connected to the signal processing circuit, the first speaker being operative to receive a first electrical signal from the signal processing circuit and to convert the first electrical signal into a first sound wave corresponding to the first ear; and

A second speaker corresponding to a second ear of the user and electrically connected to the signal processing circuit, operative to receive a second electrical signal from the signal processing circuit and to convert the second electrical signal into a second acoustic wave corresponding to the second ear, wherein

Under the input of electric signals with the same amplitude and frequency, the volume of the first sound wave output by the first loudspeaker is smaller than that of the second sound wave output by the second loudspeaker,

The sound output means may take a first length of time to convert the target sound information into the first sound wave, a second length of time to convert the target sound information into the second sound wave,

The signal processing circuit adjusts a time difference between the first time length and the second time length based on a volume difference of the first sound wave and the second sound wave to center an acoustic image between the first ear and the second ear of the user.

2. The sound output apparatus of claim 1, wherein,

The signal processing circuit generates the first electrical signal and the second electrical signal respectively based on the same signal source in operation.

3. The sound output device of claim 1, wherein the first length of time is shorter than the second length of time.

4. The sound output device of claim 1, wherein the difference between the volume of the first sound wave and the volume of the second sound wave is no greater than 3d B at the same amplitude and frequency of the input of the electrical signal.

5. The sound output device of claim 1, wherein the first speaker generates the first sound wave by exciting a first mechanical structure; and

The second speaker generates a second sound wave by exciting a second mechanical structure, wherein

The mass of the first mechanical structure is greater than the mass of the second mechanical structure, resulting in a volume of sound waves output by the first speaker being less than a volume of sound waves output by the second speaker at the same magnitude and frequency of electrical signal input.

6. The sound output apparatus of claim 1, wherein the first speaker comprises at least one of a first bone conduction speaker and a first air conduction speaker; and

The second speaker includes at least one of a second bone conduction speaker and a second air conduction speaker.

7. The sound output apparatus of claim 1, wherein the time difference occurs during the process of the sound output apparatus converting the target sound information into the first electrical signal and the second electrical signal.

8. The sound output device of claim 1, wherein the time difference occurs during the first speaker converting the first electrical signal into the first sound wave and the second speaker converting the second electrical signal into the second sound wave.

9. The sound output apparatus of claim 1, wherein the time difference is not greater than 3ms.

10. A method of adjusting an acoustic image, configured to adjust acoustic images of a first speaker and a second speaker of an acoustic output device according to any one of claims 1 to 9, comprising:

acquiring the volume difference of the first sound wave and the second sound wave; and

The time difference is adjusted.

11. The method of adjusting an acoustic image of claim 10, wherein a volume difference between the first acoustic wave and the second acoustic wave is no greater than 3dB.

12. The method of adjusting an acoustic image of claim 10, wherein said adjusting a time difference between said first acoustic wave and said second acoustic wave comprises:

a phase difference of the first sound wave and the second sound wave is adjusted.