Acoustic device

Abstract

An acoustic device (100) includes a bone conduction microphone (110) that picks up vibration when a user speaks to generate a first pickup signal: at least one air conduction microphone (120) that picks up an air conduction sound when the user speaks to generate a second pickup signal; and the processing module (130) synthesizes a voice signal reflecting the speaking content of the user according to the low-frequency component in the first pickup signal and the high-frequency component in the second pickup signal, the frequency corresponding to the low-frequency component is below the first frequency division point, the frequency corresponding to the high-frequency component is above the first frequency division point, and the resonant frequency of the bone conduction microphone (110) is higher than the first frequency division point.

Description

An acoustic device

[0001] Cross-references

[0002] This application claims priority to Chinese application No. 202310541798.X filed on May 12, 2023, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This specification relates to the field of acoustic technology, and in particular to an acoustic device. Background Art

[0004] For acoustic devices with sound pickup functions, such as headphones, unexpected changes in ambient pressure can introduce additional noise. For example, wind noise caused by airflow has non-steady-state characteristics, with its frequency and amplitude changing rapidly over time and faster than the rate of change of speech. For microphones used in daily applications, wind noise mainly comes from the pressure pulsation of the air itself, that is, when the air contacts the microphone diaphragm, it pushes the diaphragm to produce unexpected vibrations. At the same time, there is a highly random pulsating pressure with an amplitude positively correlated with the speed. Wind noise affects the microphone's ability to pick up sound signals, resulting in poor voice quality during calls.

[0005] Therefore, it is hoped to provide an acoustic device that can reduce the impact of wind noise and other noises, improve the quality of the sound signals collected, and maintain good call quality.

[0006] Summary of the Invention

[0007] One embodiment of this specification provides an acoustic device, which includes a bone conduction microphone that picks up vibrations when a user speaks to generate a first sound pickup signal; at least one air conduction microphone that picks up air-conducted sound generated by the user speaking to generate a second sound pickup signal; and a processing module that synthesizes a voice signal reflecting the content of the user's speech based on low-frequency components in the first sound pickup signal and high-frequency components in the second sound pickup signal, wherein the frequency corresponding to the low-frequency components is below a first crossover point, the frequency corresponding to the high-frequency components is above the first crossover point, and the resonant frequency of the bone conduction microphone is higher than the first crossover point.

[0008] In some embodiments, the first crossover frequency point is in the range of 500 Hz-1000 Hz.

[0009] In some embodiments, a difference between the resonant frequency of the bone conduction microphone and the first crossover point is not less than 500 Hz.

[0010] In some embodiments, the acoustic device further includes a bone conduction vibrator and an air conduction vibrator, the bone conduction vibrator outputs bone conduction sound when driven by a first sound signal, and the air conduction vibrator outputs air conduction sound when driven by a second sound signal, the first sound signal includes a component greater than a second crossover point, the second sound signal includes a component less than the second crossover point, and the first crossover point is less than the second crossover point.

[0011] In some embodiments, the second crossover frequency point is not less than 1000 Hz.

[0012] In some embodiments, the second crossover frequency point is in the range of 1000 Hz-2500 Hz.

[0013] In some embodiments, a difference between the second dividing frequency point and the first dividing frequency point is in the range of 100 Hz-2000 Hz.

[0014] In some embodiments, a ratio of the first frequency division point to the second frequency division point is in the range of 0.2-1.

[0015] In some embodiments, the acoustic device includes a housing, and the bone conduction microphone is disposed on a side of the housing for contacting human skin.

[0016] In some embodiments, the angle between the vibration direction of the bone conduction microphone and the vibration direction of the bone conduction vibrator is no greater than 25°.

[0017] In some embodiments, the at least one air conduction microphone includes a first air conduction microphone and a second air conduction microphone. When the user wears the acoustic device, a line connecting the first air conduction microphone and the second air conduction microphone points to the user's mouth area.

[0018] In some embodiments, a distance between the first air conduction microphone and the second air conduction microphone is in a range of 10 mm to 50 mm.

[0019] In some embodiments, in the wearing state, one of the first air conduction microphone and the second air conduction microphone is disposed in a low flow velocity area on a side of the acoustic device facing the back of the user's head.

[0020] In some embodiments, the processing module is further configured to: determine whether the user is in a wind noise state based on the external sound signals collected by the first air conduction microphone and the second air conduction microphone respectively; if the user is in a wind noise state, control the one of the first air conduction microphone and the second air conduction microphone that is set in a low flow rate area to collect the sound signal when the user is speaking; if the user is not in a wind noise state, control the one of the first air conduction microphone and the second air conduction microphone that is closer to the user's mouth to collect the sound signal when the user is speaking.

[0021] In some embodiments, determining whether the user is in a wind noise state based on the external sound signals respectively collected by the first air conduction microphone and the second air conduction microphone includes: determining whether the correlation between the external sound signals respectively picked up by the first air conduction microphone and the second air conduction microphone is greater than a correlation threshold; if the correlation is greater than the correlation threshold, the user is not in a wind noise state; if the correlation is less than the correlation threshold, the user is in a wind noise state.

[0022] In some embodiments, the bone conduction microphone includes a first supporting structure and a vibration pickup unit, the vibration pickup unit is located in a cavity inside the first supporting structure, the vibration pickup unit of the bone conduction microphone includes an elastic element and a mass block, the mass block is located on the elastic element, the first supporting structure vibrates in response to the vibration of the shell or human skin, and the vibration pickup unit receives the vibration of the first supporting structure and converts the vibration into an electrical signal.

[0023] In some embodiments, the bone conduction microphone includes a first supporting structure and a vibration pickup unit, the vibration pickup unit is located in a cavity inside the first supporting structure, and the first supporting structure is a closed structure.

[0024] In some embodiments, the air conduction microphone includes a second supporting structure and a diaphragm, the diaphragm is located in the cavity of the second supporting structure and divides the cavity into a front cavity and a rear cavity, and the supporting structure is provided with a hole for connecting the front cavity with the external environment.

[0025] In some embodiments, the processing module is further configured to: obtain a vibration signal through the bone conduction microphone, the vibration signal is at least partially derived from the vibration generated by the shell of the acoustic device in response to an audio signal, and the vibration of the shell of the acoustic device is configured to be transmitted to the user wearing the acoustic device in a bone conduction manner; determine the vibration response characteristics of the shell based on the vibration signal and the audio signal; and provide feedback on the working status of the acoustic device based on the vibration response characteristics of the shell.

[0026] Additional features will be described in part in the following description and will become apparent to those skilled in the art by reference to the following and accompanying drawings, or may be learned by practice or operation of the examples. The features of this specification may be realized and obtained by practicing or using the various aspects of the methods, tools, and combinations described in the following detailed examples. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] This specification will be further described in the form of exemplary embodiments, which will be described in detail with reference to the accompanying drawings. These embodiments are not limiting, and in these embodiments, like numbers represent like structures, wherein:

[0028] FIG1 is a structural block diagram of an acoustic device according to some embodiments of this specification;

[0029] FIG2 is a structural block diagram of an acoustic device according to other embodiments of this specification;

[0030] FIG3 is a schematic structural diagram of a bone conduction microphone according to some embodiments of this specification;

[0031] FIG4 is a schematic structural diagram of another bone conduction microphone according to some embodiments of this specification;

[0032] FIG5 is a schematic structural diagram of another bone conduction microphone according to some embodiments of this specification;

[0033] FIG6 is a schematic structural diagram of another air conduction microphone according to some embodiments of this specification;

[0034] FIG7 is a schematic diagram of a structure in which a sound inlet hole is provided in a housing according to some embodiments of this specification;

[0035] FIG8 is a schematic cross-sectional view along the line M1-M2 in FIG7 according to some embodiments of the present specification;

[0036] FIG9 is a schematic cross-sectional view along line M3-M4 in FIG8 according to some embodiments of the present disclosure;

[0037] FIG10 is a schematic structural diagram of a bone conduction microphone according to some embodiments of this specification;

[0038] FIG11 is a schematic structural diagram of an air conduction microphone according to some embodiments of this specification;

[0039] FIG12 is a schematic structural diagram of an acoustic device according to some embodiments of this specification. DETAILED DESCRIPTION

[0040] In order to more clearly illustrate the technical solutions of the embodiments of this specification, the following is a brief introduction to the drawings required for the description of the embodiments. Obviously, the drawings described below are only some examples or embodiments of this specification. For ordinary technicians in this field, this specification can also be applied to other similar scenarios based on these drawings without paying any creative work. It should be understood that these exemplary embodiments are provided only to enable technicians in the relevant fields to better understand and implement this specification, and do not limit the scope of this specification in any way. Unless it is obvious from the language environment or otherwise explained, the same reference numerals in the figures represent the same structure or operation.

[0041] As used in this specification and claims, unless the context clearly indicates an exception, the words "a", "an", "an" and / or "the" do not specifically refer to the singular and may also include the plural, unless the context clearly indicates an exception. Generally speaking, the terms "include" and "comprise" only indicate the inclusion of the steps and elements that have been explicitly identified, and these steps and elements do not constitute an exclusive list. The method or apparatus may also include other steps or elements. The term "based on" means "at least in part based on." The term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one other embodiment."

[0042] In the description of this specification, it should be understood that the terms "front", "rear", "ear hook", "rear hook", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing this specification and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they cannot be understood as limitations on this specification.

[0043] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. Throughout this specification, "plurality" means at least two, such as two or three, unless otherwise specifically defined.

[0044] In this specification, unless otherwise specified or limited, the terms "mounted," "connected," "connect," "fixed," etc. should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integration; mechanical connection or electrical connection; direct connection or indirect connection through an intermediate medium; internal communication between two components or interaction between two components, unless otherwise specified. Those skilled in the art will understand the specific meanings of the above terms in this specification based on specific circumstances.

[0045] An embodiment of this specification provides an acoustic device that uses a bone conduction microphone to pick up vibrations during a user's speech to generate a first sound pickup signal; uses at least one air conduction microphone to pick up the air-conducted sound of the user's speech to generate a second sound pickup signal; and uses a processing module to synthesize a speech signal reflecting the user's speech content based on low-frequency components in the first sound pickup signal and high-frequency components in the second sound pickup signal. The low-frequency components correspond to frequencies below a first crossover point, while the high-frequency components correspond to frequencies above the first crossover point. The resonant frequency of the bone conduction microphone is higher than the first crossover point, thereby reducing the impact of wind noise, improving the quality of the sound signal it collects, and maintaining good call quality. In some embodiments, the acoustic device may include a bone conduction transducer. By setting the frequency component of the electrical signal that drives the bone conduction transducer to vibrate, the user's listening experience can be optimized. Furthermore, the vibration frequency of the bone conduction transducer can be adjusted to avoid the low-frequency components in the first sound pickup signal, thereby preventing the vibration of the bone conduction transducer from affecting the sound pickup effect of the bone conduction microphone.

[0046] FIG1 is a structural block diagram of an acoustic device according to some embodiments of the present specification.

[0047] As shown in FIG1 , in some embodiments, the acoustic device 100 may include a housing, a bone conduction microphone 110 , at least one air conduction microphone 120 , and a processing module 130 , wherein the bone conduction microphone 110 , at least one air conduction microphone 120 , and the processing module 130 are located inside the housing.

[0048] The bone conduction microphone 110 refers to a device for picking up external vibration signals and converting them into electrical signals, i.e., first sound pickup signals. External vibration signals may include vibrations generated by the skin, bones, and muscles of the human body when the user speaks. In some embodiments, the bone conduction microphone 110 may receive external vibrations through a housing, which transmits the vibrations to the bone conduction microphone 110, which receives the housing vibrations and converts the vibrations into first sound pickup signals. For illustrative purposes only, the bone conduction microphone 110 described in the embodiments of this specification may be applied to headphones (e.g., bone conduction headphones, air conduction headphones, or bone-air conduction headphones), glasses, virtual reality equipment, helmets, etc. The bone conduction microphone may be placed on the human head (e.g., face, top of the head, etc.), neck, near the ears, etc. The bone conduction microphone 110 may pick up vibration signals of the skin, bones, and muscles of the user when speaking, and convert them into electrical signals to achieve sound collection. The specific structure of the bone conduction microphone will be described below in conjunction with Figures 3 to 5.

[0049] In some embodiments, the bone conduction microphone 110 may include a base structure and a laminated structure. In some embodiments, the base structure may be a regular or irregular three-dimensional structure with a hollow interior. For example, it may be a hollow frame structure, including but not limited to regular shapes such as a rectangular frame, a circular frame, and a regular polygonal frame, as well as any irregular shape. The laminated structure may be located within the hollow interior of the base structure or at least partially suspended above the hollow interior of the base structure. In some embodiments, at least a portion of the laminated structure is physically connected to the base structure. "Connected" here may be understood as, after separately preparing the laminated structure and the base structure, fixing the laminated structure and the base structure together by welding, riveting, clamping, bolting, or the like, or, during the preparation process, depositing the laminated structure on the base structure by physical deposition (e.g., physical vapor deposition) or chemical deposition (e.g., chemical vapor deposition). In some embodiments, at least a portion of the laminated structure may be fixed to the upper or lower surface of the base structure, or at least a portion of the laminated structure may be fixed to the sidewalls of the base structure. Figure 3 is a schematic structural diagram of a bone conduction microphone according to some embodiments of the present disclosure. As shown in Figure 3, in some embodiments, a bone conduction microphone 110A may include a base structure 310 and a laminated structure, wherein the laminated structure is fixedly connected to the base structure 310 in the form of a cantilever beam. Furthermore, the laminated structure may include a fixed end and a free end, wherein the fixed end of the laminated structure is fixedly connected to the frame structure, while the free end of the laminated structure is not connected to or in contact with the frame structure, allowing the free end of the laminated structure to be suspended in the air. In some embodiments, the fixed end of the laminated structure may be connected to the upper surface, lower surface, or sidewall of the hollow portion of the base structure 310. In some embodiments, the laminated structure may include an acoustic transducer unit 320 and a vibration unit 330. The vibration unit 330 refers to the portion of the laminated structure that can undergo elastic deformation, and the acoustic transducer unit 320 refers to the portion of the laminated structure that converts the deformation of the vibration unit 330 into an electrical signal. In some embodiments, the vibration unit 330 may be located on the upper or lower surface of the acoustic transducer unit 320. In some embodiments, the vibration unit 330 may include at least one elastic layer. For illustrative purposes only, the vibration unit 330 shown in FIG3 may include a first elastic layer 331 and a second elastic layer 332 arranged sequentially from top to bottom. The first elastic layer 331 and the second elastic layer 332 may be plate-shaped structures made of semiconductor materials. In some embodiments, the semiconductor material may include silicon dioxide, silicon nitride, gallium nitride, zinc oxide, silicon carbide, etc. In some embodiments, the materials of the first elastic layer 331 and the second elastic layer 332 may be the same or different.In some embodiments, the acoustic transducer unit 320 includes at least a first electrode layer 321, a piezoelectric layer 322, and a second electrode layer 323, which are arranged in sequence from top to bottom. The elastic layer (e.g., the first elastic layer 331 and the second elastic layer 332) can be located on the upper surface of the first electrode layer 321 or the lower surface of the second electrode layer 323. Based on the piezoelectric effect, the piezoelectric layer 322 can generate a voltage (potential difference) under the deformation stress of the vibration unit 330 (e.g., the first elastic layer 331 and the second elastic layer 332), and the first electrode layer 321 and the second electrode layer 323 can output the voltage (electrical signal). In some embodiments, the material of the piezoelectric layer can include piezoelectric crystal material and piezoelectric ceramic material. Piezoelectric crystal material refers to a piezoelectric single crystal. In some embodiments, the first electrode layer 321 and the second electrode layer 323 are conductive material structures. Exemplary conductive materials can include metals, alloy materials, metal oxide materials, graphene, etc., or any combination thereof.

[0050] FIG4 is a schematic diagram of the structure of a bone conduction microphone provided according to some embodiments of the present disclosure. As shown in FIG4 , in some embodiments, the bone conduction microphone 110B may include a base structure 410 and a laminated structure. The laminated structure may include an acoustic transducer unit 420 and a vibration unit. In some embodiments, the vibration unit may be disposed on the upper or lower surface of the acoustic transducer unit 420. As shown in FIG4 , the vibration unit includes a suspended membrane structure 430 and a mass element 440. The mass element 440 may be located on the upper or lower surface of the suspended membrane structure 430. In some embodiments, the suspended membrane structure 430 may be located on the upper or lower surface of the base structure 410. In some embodiments, the circumference of the suspended membrane structure 430 may also be connected to the inner wall of the hollow portion of the base structure 410. In some embodiments, the acoustic transducer unit 420 may include a first electrode layer, a second electrode layer, and a piezoelectric layer located between the two electrode layers. The first electrode layer, the piezoelectric layer, and the second electrode layer are combined to form a structure that is adapted to the shape of the mass element 440. For example, the mass element 440 is a cylindrical structure, and the acoustic transducer unit 420 can be a ring structure. In this case, the first electrode layer, the piezoelectric layer, and the second electrode layer are all ring structures, and the three are arranged in sequence from top to bottom to form a ring structure.

[0051] In some embodiments, the laminated structure may include a mass element and one or more support arms. The mass element is fixedly connected to the base structure via the one or more support arms. One end of each support arm is connected to the base structure, and the other end of each support arm is connected to the mass element, so that portions of the mass element and the support arms are suspended within the hollow portion of the base structure. Figure 5 is a schematic diagram of the structure of a bone conduction microphone according to some embodiments of this specification. As shown in Figure 5, a bone conduction microphone 110C may include a base structure 510 and a laminated structure. The laminated structure includes four support arms 530 and a mass block 540. One end of each of the four support arms 430 is connected to the upper surface, lower surface, or sidewall of the hollow portion of the base structure 410, and the other end of each of the four support arms 430 is connected to the upper surface, lower surface, or circumferential sidewall of the mass element 440. The support arm 430 may include at least one elastic layer. The elastic layer may be a plate-like structure made of a semiconductor material. In some embodiments, the materials of the different elastic layers of the support arm 430 may be the same or different. Furthermore, the bone conduction microphone 110C may include an acoustic transducer unit 420. The acoustic transducer unit 420 may include a first electrode layer, a piezoelectric layer, and a second electrode layer arranged in sequence, wherein the first electrode layer or the second electrode layer is connected to the upper surface or the lower surface of the support arm 430 (e.g., the elastic layer). In some embodiments, when the support arm 430 comprises multiple elastic layers, the acoustic transducer unit 420 may also be located between the multiple elastic layers. The piezoelectric layer may generate a voltage (potential difference) under the deformation stress of the vibration unit (e.g., the support arm 430 and the mass element 440) based on the piezoelectric effect, and the first electrode layer and the second electrode layer may derive the voltage (electrical signal).

[0052] It should be noted that, in the present application, “located in the hollow part of the base structure” or “suspended in the hollow part of the base structure” may mean suspended inside, below or above the hollow part of the base structure. Specifically, the base structure can generate vibrations based on an external vibration signal, and the vibration unit deforms in response to the vibration of the base structure; the acoustic transducer unit generates an electrical signal based on the deformation of the vibration unit. It should be noted that the description of the vibration unit and the acoustic transducer unit here is only for the purpose of conveniently introducing the working principle of the laminated structure, and does not limit the actual composition and structure of the laminated structure. In fact, the vibration unit may not be necessary, and its function can be fully realized by the acoustic transducer unit. For example, after making certain changes to the structure of the acoustic transducer unit, the acoustic transducer unit can directly respond to the vibration of the base structure to generate an electrical signal.

[0053] The air conduction microphone 120 is a transducer device that picks up air-conducted sound propagating through the air to generate an electrical signal, i.e., a second sound pickup signal. Air-conducted sound can include sound waves generated by the vibration of the surrounding air when a user speaks. Figure 6 is an exemplary structural diagram of an air conduction microphone provided according to an embodiment of this specification. As shown in Figure 6, in some embodiments, the air conduction microphone 120 may include a sound sensor 122, a processing circuit 123, etc. The sound sensor 122 and the processing circuit 123 are located within the housing of the acoustic device and are electrically connected to the sound sensor 122 and the processing circuit 123 via leads. The sound sensor 122 is used to convert the air-conducted sound into an electrical signal. In some embodiments, the sound sensor 122 may include any one or more of a dynamic coil sound sensor, a moving iron sound sensor, a capacitive sound sensor, a piezoelectric sound sensor, a MEMS sound sensor, etc. The processing circuit 123 is used to receive and process the electrical signal from the sound sensor 122. In some embodiments, the processing circuit 123 may include an amplifier, a filter processor, etc. Taking a dynamic sound sensor as an example, the dynamic sensor includes at least a diaphragm, a coil and a magnetic circuit structure (not shown in Figure 6). A sound inlet hole 124 is opened on the shell, and the external sound transmits the air-conducted sound waves to the inside of the shell through the sound inlet hole 124. The pressure change inside the shell causes the diaphragm to vibrate, and the coil moves in response to the vibration of the diaphragm. The coil moves in the magnetic field of the magnetic circuit structure and generates an electrical signal.

[0054] In some embodiments, the shape of the housing of the acoustic device can be a rectangular parallelepiped, a substantially rectangular parallelepiped, a cylinder, a sphere, or any other arbitrary shape. The housing encloses a housing space, and the air conduction microphone 120 is disposed within the housing space. The bone conduction microphone 110 can be disposed on the outer surface of the housing or within the housing. In some embodiments, the bone conduction microphone 110 and the air conduction microphone 120 are physically connected to the housing. Specifically, the physical connection method can include welding, snap-fitting, bonding, or integral molding, and the connection method is not limited here. In some embodiments, the housing can be made of a material with a certain hardness so that the housing can protect the bone conduction microphone 110 and the air conduction microphone 120 and other internal components. In some embodiments, the material of the housing can include, but is not limited to, one or more of metals, alloy materials (such as aluminum alloys, chromium-molybdenum steel, scandium alloys, magnesium alloys, titanium alloys, magnesium-lithium alloys, nickel alloys, etc.), glass fiber or carbon fiber, polymer materials (such as acrylonitrile-butadiene-styrene copolymers, polyvinyl chloride, polycarbonate, polypropylene, etc.), etc.

[0055] The processing module 130 can perform signal processing on the first sound pickup signal converted by the bone conduction microphone 110 and the second sound pickup signal converted by the air conduction microphone 120, ultimately generating a speech signal reflecting the user's speech content. In some embodiments, the processing module 130 can extract different frequency components from the first and second sound pickup signals, for example, extracting low-frequency components from the first sound pickup signal and high-frequency components from the second sound pickup signal, and synthesize a speech signal based on the extracted frequency components. The low-frequency components are the signal portions of the first sound pickup signal corresponding to low-frequency sounds, and the high-frequency components are the signal portions of the first sound pickup signal corresponding to high-frequency sounds. In actual applications, the speech signal reflecting the user's speech content generated by the processing module 130 based on the different frequency components extracted from the first and second sound pickup signals generally exhibits splicing artifacts. These splicing artifacts can indicate the absence of speech signals near the first crossover frequency (i.e., within the range of ±300 Hz of the first crossover frequency) or a significant difference in the amplitude of the speech signals. In some embodiments, the low-frequency and high-frequency components can be distinguished at specific frequency points, as described below. The above-mentioned signal processing may include, but is not limited to, one or more of signal amplification, phase adjustment, and filtering. In some embodiments, the processing module 130 may include, but is not limited to, an equalizer (EQ), a dynamic range controller (DRC), a phase processor (GAIN), and the like. The processing module 130 is not limited to the aforementioned circuit structure for signal processing. In some embodiments, the processing module 130 may also be a computer storage medium containing a processing algorithm. It should be noted that the processing module 130 may also function as the processing circuit 123 of the air conduction microphone 120, in which case the processing circuit 123 may be omitted.

[0056] When a user speaks, the vibrations generated by low-frequency sounds, compared to high-frequency sounds, are effectively transmitted to the skin through the body's bones and muscles. In this case, using the bone conduction microphone 110 to capture the vibrations emitted by the user's speech can effectively pick up the low-frequency information. Furthermore, although wind noise is primarily concentrated in low frequencies, since wind noise primarily relies on air conduction, the low-frequency components captured by the bone conduction microphone 110 are rarely affected by wind noise. In other words, the low-frequency components of the bone conduction microphone 110 can mitigate the effects of wind noise. Furthermore, wind noise has a weaker effect on high-frequency sounds. Using the air conduction microphone 120 to capture the air-conducted sound emitted by the user's speech can effectively capture the high-frequency information. In some embodiments, the user's speech is captured by the bone conduction microphone 110 and the air conduction microphone 120, respectively. Signal processing is performed by the processing module 130 to obtain the low-frequency components of the first picked-up signal and the high-frequency components of the second picked-up signal, respectively. These signals are then synthesized into the user's speech signal. This reduces the impact of wind noise while improving the quality of the sound signals in different frequency bands captured by the acoustic device 100.

[0057] In some embodiments, the frequency corresponding to the low-frequency component is below a first crossover point, and the frequency corresponding to the high-frequency component is above the first crossover point. The first crossover point is the sound frequency that distinguishes the low-frequency component from the high-frequency component. It should be noted that the frequency corresponding to the low-frequency component is a sound frequency below the first crossover point, and the frequency corresponding to the high-frequency component is a sound frequency above the first crossover point.

[0058] The impact of wind noise on the sound of a user speaking is primarily in the frequency band below 1000Hz, and exhibits a characteristic of decreasing from low frequency to high frequency. Based on this, in order to reduce the impact of wind noise on the sound signal of the user speaking collected by the microphone, in some embodiments, the first crossover frequency can be in the range of 500Hz-1000Hz. In this case, the bone conduction microphone is in contact with the user's facial skin and collects sound signals below the first crossover frequency based on the facial vibrations of the user when speaking, greatly reducing the impact of wind noise on the sound of the user speaking in the low-frequency band. Furthermore, the impact of wind noise on the sound of the user speaking is very weak. Using an air conduction microphone to collect the air-conducted sound emitted by the user speaking, that is, using an air conduction microphone to collect sound signals above the first crossover frequency, can effectively pick up the high-frequency information therein.

[0059] In some embodiments, the first crossover frequency may be 500 Hz, in which case the low-frequency components of the first sound pickup signal may include frequency components in the range of 20 Hz to 500 Hz, and the high-frequency components of the second sound pickup signal may include frequency components above 500 Hz (e.g., 500 Hz to 8000 Hz). In some embodiments, the first crossover frequency may be 800 Hz, in which case the low-frequency components of the first sound pickup signal may include frequency components in the range of 20 Hz to 800 Hz, and the high-frequency components of the second sound pickup signal may include frequency components above 800 Hz (800 Hz to 8000 Hz). In some embodiments, the first crossover frequency may be 900 Hz, in which case the low-frequency components of the first sound pickup signal may include frequency components in the range of 20 Hz to 900 Hz, and the high-frequency components of the second sound pickup signal may include frequency components above 900 Hz (900 Hz to 8000 Hz). In some embodiments, the first crossover point may be 1000 Hz. In this case, the low-frequency component of the first sound pickup signal may include frequency components of 20 Hz-1000 Hz, and the high-frequency component of the second sound pickup signal may include frequency components above 1000 Hz (for example, 1000 Hz-8000 Hz).

[0060] It should be noted that for sound frequencies below the first crossover point, wind noise has less impact on the bone conduction microphone 110, but has a greater impact on the air conduction microphone 120. At this time, the low-frequency component in the sound signal picked up by the bone conduction microphone 110 can more accurately reflect the low-frequency information in the user's voice; for sound frequencies above the first crossover point, the transmission of vibrations by the human skeleton and skin will cause greater attenuation. Compared with the bone conduction microphone 110, the high-frequency component in the sound signal picked up by the air conduction microphone 120 can better reflect the high-frequency information in the user's voice.

[0061] In some embodiments of this specification, by setting a first crossover point, the optimal portion of the audio signals picked up by the bone conduction microphone 110 and the air conduction microphone 120 can be accurately extracted to synthesize the voice signal of the user speaking; by utilizing the pickup advantages of the bone conduction microphone 110 and the air conduction microphone 120 in different sound frequency bands, the overall quality of the voice signal of the user speaking is improved.

[0062] In some embodiments, the first crossover frequency point can be determined based on the physical or electronic characteristics of the bone conduction microphone 110 and the air conduction microphone 120. For example, a spectrogram of the final synthesized speech signal of the acoustic device 100 is obtained, and the frequency at which the signal amplitude in the spectrogram undergoes a sudden change or the frequency range at which a discontinuous change occurs is determined. The first crossover frequency point is then determined based on this frequency or frequency range. As an example only, the frequency at which the signal amplitude in the spectrogram undergoes a sudden change can be used as the first crossover frequency point, or the frequency range at which the signal amplitude in the spectrogram undergoes a discontinuous change can be used as the range of the first crossover frequency point. The first crossover frequency point can be selected within this range.

[0063] In some embodiments, the processing module 130 may perform low-pass filtering on the first sound pickup signal through a low-pass filter to obtain low-frequency components, perform high-pass filtering on the second sound pickup signal through a high-pass filter to obtain high-frequency components, and splice the obtained low-frequency components and high-frequency components to obtain a complete voice signal.

[0064] In some embodiments, the cutoff frequency of the low-pass filter is the first crossover frequency point. After the first sound pickup signal generated by the bone conduction microphone 110 is processed by low-pass filtering, the portion greater than the cutoff frequency, i.e., the first crossover frequency point, is filtered out, thereby mainly retaining low-frequency components below the cutoff frequency. Similarly, the cutoff frequency of the high-pass filter is the first crossover frequency point. After the second sound pickup signal generated by the air conduction microphone 120 is processed by high-pass filtering, the portion less than the cutoff frequency, i.e., the first crossover frequency point, is filtered out, thereby mainly retaining high-frequency components above the cutoff frequency. In some embodiments, the cutoff frequency of the low-pass filter can be lower than the cutoff frequency of the high-pass filter, thereby clearly distinguishing the low-frequency components of the first sound pickup signal from the high-frequency components of the second sound pickup signal. In some embodiments, the cutoff frequency of the low-pass filter can also be higher than the cutoff frequency of the high-pass filter, so that the low-frequency components of the first sound pickup signal and the high-frequency components of the second sound pickup signal have overlapping frequency components, effectively mitigating the sudden changes in the final synthesized speech signal near the first crossover frequency point. In some embodiments, the difference between the cutoff frequency of the high-pass filter and the cutoff frequency of the low-pass filter can be within the range of 200 Hz, so that the low-frequency and high-frequency components of the signal synthesized by the processing module 130 have high quality while avoiding the influence of wind noise. It should be noted that the filters (e.g., high-pass filters and low-pass filters) referred to in this specification can be electronic components or computer media containing filtering processing algorithms.

[0065] In some embodiments, the resonant frequency of the bone conduction microphone 110 is higher than the first crossover frequency point.

[0066] In some embodiments of this specification, the bone conduction microphone 110 exhibits a rapid frequency attenuation after the resonant peak in its frequency response curve, affecting the quality of the collected sound. By setting the resonant frequency of the bone conduction microphone 110 higher than the first crossover frequency, the frequency response curve of the bone conduction microphone 110 can be relatively flat and maintain a high amplitude before the first crossover frequency, allowing the bone conduction microphone to effectively capture more low-frequency components and ensure the quality of the synthesized sound. In some embodiments, the resonant frequency of the bone conduction microphone 110 can be in the range of 2kHz-5kHz. In some embodiments, to increase the sensitivity of the bone conduction microphone 110 to low-frequency vibrations, the difference between the resonant frequency of the bone conduction microphone 110 and the first crossover frequency can be set to no more than 4kHz. In some embodiments, the difference between the resonant frequency of the bone conduction microphone 110 and the first crossover frequency can be set to no more than 3kHz. In some embodiments, to improve the flatness of the frequency response curve of the bone conduction microphone 110 at the first crossover frequency, the difference between the resonant frequency of the bone conduction microphone 110 and the first crossover frequency can be set to no less than 500Hz. In some embodiments, the difference between the resonant frequency of the bone conduction microphone 110 and the first crossover frequency point may be set to be no less than 1 kHz.

[0067] FIG2 is a structural block diagram of an acoustic device according to other embodiments of this specification.

[0068] As shown in Figure 2, in some embodiments, the acoustic device 100 also includes a bone conduction vibrator 140 and an air conduction vibrator 150. The bone conduction vibrator 140 outputs bone conduction sound when driven by a first sound signal, and the air conduction vibrator 150 outputs air conduction sound when driven by a second sound signal. The first sound signal may include a component greater than the second crossover point, and the second sound signal may include a component less than the second crossover point.

[0069] The second crossover frequency point can be used to define the frequency components of the electrical signal containing sound information from the speaker (bone conduction vibrator 140 and air conduction vibrator 150). In some embodiments, the processing module 130 can divide the input electrical signal containing voice information into a first sound signal and a second sound signal based on the second crossover frequency point, and send them to the bone conduction vibrator 140 and the air conduction vibrator 150, respectively, to generate corresponding sounds.

[0070] In some embodiments, the bone conduction vibrator 140 may include a magnetic circuit structure, a coil, a vibration transmission member, and a vibration plate (which may also be the housing of an acoustic device). The coil generates a magnetic field change based on an electrical signal. The magnetic circuit structure generates vibrations in response to the magnetic field change and transmits the vibrations to the vibration plate or the housing of the acoustic device via the vibration transmission member. When a user wears the acoustic device 100, the vibration plate or the housing of the acoustic device may come into contact with the user's skin, transmitting the vibrations to the auditory nerve through the skin, skeletal muscles, and bone-conducted sound waves, thereby enabling the user to hear sounds. In some embodiments, the shape of the housing of the acoustic device may be cylindrical, truncated cone, rectangular parallelepiped, or other three-dimensional structures. In some embodiments, the material of the housing of the acoustic device may include plastic, resin, glass, metal, etc. In some embodiments, the contact area may be a side wall of the housing. For example, when the housing of the acoustic device is a cylindrical structure, the contact area is the bottom wall of the housing of the acoustic device. In some embodiments, the contact area may also be a local area of ​​a side wall of the housing of the acoustic device. For example, a side wall of the housing of the acoustic device may have a protrusion protruding relative to its surface, and this protrusion is the contact area. In some embodiments, the bone conduction vibrator 140 may include a vibration plate and a transducer. The transducer may be configured to generate vibrations, for example, by converting an electrical signal corresponding to the first sound signal into mechanical vibrations. The transducer may drive the vibration plate to vibrate. As an example only, the vibration plate may be mechanically connected to the transducer and vibrate with the transducer. In actual application (e.g., when a user wears the acoustic device 100), the vibration plate may contact the user's skin and transmit the vibrations to the auditory nerve through human tissue and bones, thereby enabling the user to hear the sound.

[0071] In some embodiments, the air conduction vibrator 150 may include a transducer and a diaphragm, which are located inside the housing of the acoustic device. The transducer can receive the second sound signal from the processing module 130 and drive the diaphragm to vibrate, thereby generating air-conducted sound waves. In some embodiments, the air conduction vibrator 150 can be an open structure, which is located near the user's ear but does not block the ear canal. Accordingly, the housing of the acoustic device includes at least a contact area that can contact the user's facial area. In some embodiments, the transducer can include an electromagnetic type (e.g., a moving coil type, a moving iron type, etc.), a piezoelectric type, an inverse piezoelectric type, an electrostatic type, etc. In some embodiments, the housing of the acoustic device may include one or more sound guide holes. When the user wears the acoustic device 100, the sound guide holes face the user's ear canal opening. The sound guide holes are used to connect the internal cavity of the housing with the outside world. The sound guide holes can transmit the air-conducted sound waves inside the housing of the acoustic device to the outside world, thereby transmitting the sound to the user in an air-conducted manner.

[0072] In some embodiments, the processing module 130 may perform high-pass filtering and low-pass filtering on the electrical signal containing the sound information to obtain the first sound signal and the second sound signal.

[0073] In some embodiments, the high-pass filter's cutoff frequency is the second crossover frequency point. After the electrical signal containing sound information is processed by the high-pass filter, the portion below the cutoff frequency, i.e., the second crossover frequency point, is filtered out, thereby primarily retaining high-frequency components above the cutoff frequency. Processing module 130 classifies the input electrical signal containing voice information into a first sound signal based on this high-frequency component. Similarly, the low-pass filter's cutoff frequency is the second crossover frequency point. After the electrical signal containing sound information is processed by the low-pass filter, the portion above the cutoff frequency, i.e., the second crossover frequency point, is filtered out, thereby primarily retaining low-frequency components below the cutoff frequency. Processing module 130 classifies the input electrical signal containing voice information into a second sound signal based on this low-frequency component. In some embodiments, the cutoff frequency of the low-pass filter can be lower than the cutoff frequency of the high-pass filter. In some embodiments, the cutoff frequency of the low-pass filter can also be higher than the cutoff frequency of the high-pass filter. If the frequency components of the first and second sound signals overlap, the overlapping frequency components can simultaneously generate bone-conducted sound and air-conducted sound, thereby improving the user's listening experience. In some embodiments, the difference between the cutoff frequency of the high-pass filter and the cutoff frequency of the low-pass filter can be in the range of -200Hz-200Hz, so that the low-frequency and high-frequency components of the signal synthesized by the processing module 130 have higher quality while avoiding the influence of wind noise.

[0074] In some other embodiments, the processing module 130 may further process the electrical signal containing the sound information through other processing methods to obtain the first sound signal and the second sound signal. For example, the processing module 130 may include an audio power amplifier to amplify the input electrical signal containing the voice information to an appropriate level, thereby obtaining the first sound signal and the second sound signal of sufficient level.

[0075] In some embodiments, the electrical signal containing sound information is referred to as an audio signal. An audio signal is an information carrier that carries regular frequency and amplitude variations of sound waves that carry speech, music, and sound effects. In some embodiments, the audio signal can be stored in the internal memory of the acoustic device 100 or transmitted between devices via a communication connection. For example, the audio signal stored in the acoustic device 100 can include white noise, pure tone signals, pulse signals, narrowband noise, narrowband warbling, modulated tones, and / or swept tone signals, or music signals.

[0076] In some embodiments, the acoustic device 100 can output bone-conducted sound via the bone conduction transducer 140. However, the vibrations generated by the bone conduction transducer 140 are inevitably picked up by the bone conduction microphone 110, resulting in an echo in the sound output by the acoustic device 100. In some embodiments, the second crossover frequency is greater than the first crossover frequency, allowing the bone conduction transducer 140 to output bone-conducted sound above the second crossover frequency, avoiding the frequency range where the low-frequency components primarily picked up by the bone conduction microphone 110 reside, thereby effectively preventing the bone conduction transducer 140 from affecting the bone conduction microphone 110. Furthermore, because air-conducted sound waves have little impact on the bone conduction microphone 110, the air conduction transducer 150 outputs electrical signals containing sound information below the second crossover frequency as air-conducted sound, ensuring that the user can still hear sounds below the second crossover frequency.

[0077] In some embodiments, the first crossover point may be in the range of 500Hz-1000Hz, and the second crossover point may be in the range of 1000Hz and above. In some embodiments, the second crossover point may be no less than 1 times, 1.4 times, 1.5 times, 2 times or more than 2 times the first crossover point. Preferably, the second crossover point is in the range of 1000Hz-3000Hz. More preferably, the second crossover point is in the range of 1300Hz-2500Hz. In some embodiments, by setting the second crossover point to be no less than 1000Hz, it is possible to effectively avoid the bone conduction sound output by the bone conduction vibrator 140 affecting the pickup of the bone conduction microphone 110, ensure that the voice signal generated by the bone conduction microphone 110 does not have an echo, and improve the quality of the synthesized voice reflecting the user's speech content.

[0078] It should be noted that because the low-frequency components extracted from the first sound pickup signal may still contain a portion of the voice signal after the first crossover frequency, in order to better prevent the bone conduction vibrator 140 from affecting the bone conduction microphone 110, the difference between the first crossover frequency and the second crossover frequency should not be too small. Furthermore, within a specific frequency band (e.g., 1000Hz-2000Hz), bone conduction sound is superior to air conduction sound. Therefore, while the second crossover frequency is greater than the first crossover frequency, it should not be excessively greater than the first crossover frequency, thereby ensuring a better listening experience for the user.

[0079] In some embodiments, the difference between the second crossover point and the first crossover point can be in the range of 100 Hz-1700 Hz, 300 Hz-1700 Hz, or 500 Hz-1500 Hz. In some embodiments, the ratio of the first crossover point to the second crossover point can be in the range of 0.2-1, 0.3-0.8, or 0.3-0.9. Preferably, the ratio of the first crossover point to the second crossover point is in the range of 0.3-0.8.

[0080] In some embodiments of the present specification, by setting the second crossover frequency point to be no greater than the first crossover frequency point, the acoustic device 100 is ensured to use the bone conduction vibrator 140 to output the voice signal in a specific frequency band as bone conduction sound with better effect, and the bone conduction sound output by the bone conduction vibrator 140 is prevented from affecting the bone conduction microphone 110 in picking up the user's voice, and the acoustic device 100 is prevented from generating echoes, thereby improving the quality of the voice that ultimately reflects the user's speech.

[0081] In some embodiments, based on the frequency response curves of the signals output by the bone conduction vibrator 140 and the air conduction vibrator 150 under white noise or swept frequency excitation, the corresponding frequency near the intersection of the two frequency response curves is determined as the second crossover frequency point of the acoustic device 100. In some embodiments, the second crossover frequency point is any point within a range of ±300 Hz from the intersection of the two frequency response curves. Specifically, in some embodiments, the frequency response curve of the bone conduction vibrator 140 is measured as follows: an air conduction microphone is placed within 1 cm to 2 cm of the bone conduction vibrator 140. When in operation, the bone conduction vibrator 140 causes the nearby air to vibrate, and this vibration is transmitted to the air conduction microphone via air conduction. The air conduction microphone collects this vibration to obtain the frequency response curve of the bone conduction vibrator 140.

[0082] In some embodiments, the acoustic device 100 may include a housing, and the bone conduction microphone 110 is disposed on the housing of the acoustic device 100. For the description of the housing, reference may be made to the above description.

[0083] In some embodiments of this specification, by placing the bone conduction microphone 110 on the side of the housing that contacts the human face, the damping of the facial skin provides friction and cushioning for the bone conduction microphone 110. This prevents the housing from being excited by the wind in high wind speeds, generating noise and vibration signals that could affect the bone conduction microphone 110. This in turn reduces the impact of airflow turbulence on the bone conduction microphone 110, thereby reducing wind noise. Furthermore, placing the bone conduction microphone 110 on the face-facing side facilitates the detection of skin vibrations when the user speaks, achieving better sound pickup.

[0084] It is understood that in other embodiments of the present application, the bone conduction microphone 110 may also be disposed at other locations on the housing, for example, on a side adjacent to the side in contact with human skin, or on a surface opposite the side in contact with human skin. In some embodiments, the bone conduction microphone 110 may also be disposed inside the housing. The housing may receive vibrations from the user's skin when speaking, and the bone conduction microphone 110 receives the vibrations and converts them into electrical signals (first sound pickup signals).

[0085] In some embodiments, to ensure high vibration transmission efficiency of the bone conduction vibrator 140, the vibration direction of the bone conduction vibrator 140 is typically approximately perpendicular to the face-facing side of the acoustic device's housing or the vibration plate. Approximately perpendicular here can be understood as being within a range of 70°-120°. In some embodiments, the angle between the vibration direction (i.e., the sensitive direction) of the bone conduction microphone 110 and the vibration direction of the bone conduction vibrator 140 is no greater than 25°. In some embodiments of this specification, based on the fact that the vibration direction of the bone conduction vibrator 140 is typically approximately perpendicular to the face-facing side of the acoustic device's housing or the vibration plate, by setting the angle between the vibration direction of the bone conduction microphone 110 and the vibration direction of the bone conduction vibrator 140 to no greater than 25°, the vibration transmission efficiency of the bone conduction vibrator 140 in transmitting bone-conducted sound through the face is effectively ensured. Furthermore, the bone conduction microphone 110 also has high vibration pickup efficiency at this angle.

[0086] In some embodiments, the angle between the vibration direction of the bone conduction microphone 110 and the vibration direction of the bone conduction vibrator 140 may also be within the range of 0°-15° or 5°-25°. In this embodiment, the vibration direction of the bone conduction microphone 110 is parallel to the vibration direction of the bone conduction vibrator 140, i.e., the angle is 0°. The vibration direction of the bone conduction microphone 110 and the vibration direction of the bone conduction vibrator 140 remain substantially consistent, enabling the bone conduction microphone 110 to achieve the highest vibration pickup efficiency.

[0087] In some embodiments, the at least one air conduction microphone 120 may include a first air conduction microphone and a second air conduction microphone. When the user wears the acoustic device 100 , a line connecting the first air conduction microphone and the second air conduction microphone points to the user's mouth area.

[0088] The above-mentioned line connecting the first air conduction microphone and the second air conduction microphone pointing to the user's mouth area means that the line connecting the center of the sound inlet corresponding to the first air conduction microphone and the center of the sound inlet corresponding to the second air conduction microphone points to the user's mouth area.

[0089] In some embodiments, when acoustic device 100 includes two air conduction microphones 120, the first air conduction microphone is positioned closer to the user's mouth, while the second air conduction microphone is positioned farther from the mouth than the first, thereby ensuring the directionality of the aforementioned connection line. Furthermore, the time difference between the sound captured by the first and second air conduction microphones can be used to determine the direction of the sound source. Signal processing techniques (such as differential, subtraction, and beamforming) can then be used to effectively reduce interference from ambient noise on the voice signal, thereby obtaining a clearer voice signal.

[0090] In some embodiments of this specification, by providing a first air conduction microphone 120-1 and a second air conduction microphone 120-2 so that the line connecting the two air conduction microphones (and their corresponding sound inlet ports) points toward the user's mouth, the first air conduction microphone 120-1 and the second air conduction microphone 120-2 can form a basic microphone array, which can be easily processed to reduce ambient noise, thereby ensuring that the air conduction microphones have better sound pickup when the user wears the headset. Furthermore, the voice pickup effect can be maximized, further ensuring that the air conduction microphones have better sound pickup when the user wears the headset.

[0091] In an embodiment of the present application, at least one of the first air conduction microphone 120-1 and the second air conduction microphone 120-2 can be set in a low flow rate area, wherein the low flow rate area refers to a position where the wind speed is relatively low compared to other positions when the acoustic device 100 of the present application is worn for cycling, running, or other sports. For example, the low flow rate area may include the side of the ear hook of the acoustic device 100 facing the back of the head or the side of the housing of the acoustic device 100 facing the back of the head. When the acoustic device 100 of the present application is worn for cycling, running, or other sports, at least one of the first air conduction microphone 120-1 and the second air conduction microphone 120-2 is in a position with low wind speed and is less affected by wind noise, thereby ensuring that at least one air conduction microphone can have a good sound pickup effect and that a good call effect can still be achieved during exercise.

[0092] In specific application scenarios, such as when a user is using the acoustic device 100 for a call or recording, the processing module 130 can also determine whether the user is experiencing wind noise based on the external sound signals collected by the first and second air conduction microphones 120-1, 120-2. If the user is experiencing wind noise, the processing module 130 controls one of the first and second air conduction microphones 120-1, 120-2 located in a low-flow area (e.g., the side of the earhook facing the back of the head or the area on the acoustic device 100 housing facing the back of the head) to collect the sound signal from the user's speech. This reduces the impact of wind noise on the sound signal collected by the air conduction microphones, thereby improving the sound pickup effect of the air conduction microphones in the acoustic device 100. If the user is not experiencing wind noise, the processing module 130 controls the microphone of the first and second air conduction microphones 120-1, 120-2 located near the user's mouth to collect the sound signal from the user's speech. In this case, the air conduction microphone located near the user's mouth is closer to the user's mouth and receives a stronger sound signal from the user's speech.

[0093] In some embodiments, determining whether the user is experiencing a wind noise condition based on the sound signals collected by first air conduction microphone 120-1 and second air conduction microphone 120-2, respectively, may include determining whether a correlation between the external sound signals collected by first air conduction microphone 120-1 and second air conduction microphone 120-2, respectively, is greater than a correlation threshold (e.g., 90%). If the correlation is greater than the correlation threshold, the user is not experiencing a wind noise condition; if the correlation is less than the correlation threshold, the user is experiencing a wind noise condition. Specifically, conventional noise in the external environment (e.g., speech of other people near the user, external car horns, music, etc.) is transmitted simultaneously to first air conduction microphone 120-1 and second air conduction microphone 120-2. However, first air conduction microphone 120-1 and second air conduction microphone 120-2 are located at different positions in the acoustic device. Wind noise is typically transmitted in a delayed manner in a specific direction, resulting in significant differences in the external sound signals collected by first air conduction microphone 120-1 and second air conduction microphone 120-2. Based on this principle, in different scenarios, the working states of different air conduction microphones in the acoustic device 100 can be changed to reduce the impact of external wind noise on the sound signal picked up when the user is speaking.

[0094] In some embodiments, the acoustic device 100 may have only one air conduction microphone 120 .

[0095] In some embodiments, when the acoustic device 100 has only one air conduction microphone 120, the air conduction microphone 120 can be placed in a low-flow area of ​​the acoustic device 100. For example, the low-flow area can include the side of the ear hook of the acoustic device 100 facing the back of the head or the side of the acoustic device housing 100 facing the back of the head. If the distance between the first microphone and the second microphone is too small, the amplitude and phase difference between the low-frequency sound signals received by the first and second microphones will be too small, making subsequent processing of the low-frequency signals more difficult. Therefore, the distance between the first and second microphones should not be too small. To ensure the portability of the headphones and the user's comfort when wearing the headphones, the size of the acoustic device itself should not be too large. Accordingly, the distance between the first and second microphones is limited by the size of the acoustic device itself. In some embodiments, the distance between the first and second microphones is no more than 50 mm. In some embodiments, considering the size limitation of the acoustic device itself and in order to ensure that the first microphone and the second microphone have better sound pickup effects and facilitate subsequent signal processing, the distance between the first air conduction microphone and the second air conduction microphone can be within the range of 10mm-50mm.

[0096] Figure 7 is a structural schematic diagram of a sound inlet hole opened in a shell according to some embodiments of the present specification; Figure 8 is a schematic diagram of a cross-sectional view along M1-M2 in Figure 7 according to some embodiments of the present specification; Figure 9 is a schematic diagram of a cross-sectional view along M3-M4 in Figure 8 according to some embodiments of the present specification.

[0097] Referring to Figures 7, 8, and 9, in some embodiments, an air conduction microphone 120 is disposed within the housing 101 of the acoustic device 100 and collects air-conducted sound waves through a sound inlet 1011 of the housing 101. In some embodiments, a sound guide channel 102 is disposed between the sound inlet 1011 and the air conduction microphone 120. In some embodiments, the length of the sound guide channel 102 can be set within a range of 3 mm to 20 mm.

[0098] Optionally, at least two sound inlet holes 1011 are provided on the shell 101. The air conduction microphone 120 can be used to collect external sounds input through the sound inlet holes 1011. In the embodiment of the present application, one air conduction microphone 120 can collect external sounds input through two sound inlet holes 1011. The sound input ends of the two sound inlet holes 1011 can be spaced apart from each other, and the sound output ends of the two sound inlet holes 1011 can be connected to each other. The sound input end of the sound inlet hole 1011 can refer to the end where the external sound enters the sound inlet hole 1011. The sound output end of the sound inlet hole 1011 can refer to the end where the external sound flows out after passing through the sound inlet hole 1011. By connecting the sound output ends of the two sound inlet holes 1011 to each other, pressure balance can be achieved in the entire sound guide channel 102, thereby avoiding the situation where the external pressure change is directly transmitted to the air conduction microphone 120 due to airflow stagnation.

[0099] In this embodiment, the ratio of the distance between the sound inlet ends of the two sound inlet holes 1011 to the apertures of the two sound inlet holes 1011 is between 0.5 and 3.

[0100] Optionally, the sound input end of the sound inlet 1011 is located on the side of the shell 101 toward the top of the user's head along the vertical axis of the user, and is blocked by the shell 101 or the wearing component along the sagittal axis of the user. That is, the sound input end can be located on the upper back side of the shell 101. In this case, the sound input end of the sound inlet 1011 can be opened in a relatively hidden area in the shell 101, blocked by the shell 101 or the wearing component (ear hook), thereby increasing the difficulty of external airflow entering the sound inlet 1011, thereby reducing wind noise.

[0101] It should be noted that in fields such as medicine and anatomy, the human body can be defined as three basic planes: the sagittal plane, the coronal plane, and the horizontal plane, as well as three basic axes: the sagittal axis, the coronal axis, and the vertical axis. The sagittal plane refers to a plane perpendicular to the ground, along the anterior-posterior direction of the body, dividing the body into left and right halves. The coronal plane refers to a plane perpendicular to the ground, along the lateral direction of the body, dividing the body into anterior-posterior halves. The horizontal plane refers to a plane parallel to the ground, along the lateral direction of the body, dividing the body into upper and lower halves. Accordingly, the sagittal axis refers to the axis along the lateral direction of the body and perpendicular to the coronal plane; the coronal axis refers to the axis along the lateral direction of the body and perpendicular to the sagittal plane; and the vertical axis refers to the axis along the lateral direction of the body and perpendicular to the horizontal plane.

[0102] Specifically, for users, in most scenarios, they move forward, which means that when wearing headphones, the airflow mainly comes from the front of the user (headphones). Therefore, by placing the sound input end at the rear of the housing 101, most of the airflow from the front of the user can be blocked by the housing 101, and it is not easy to enter the sound inlet 1011. In addition, the auricle of the ear may have a sound-gathering effect, reducing the quality of the sound collected by the air conduction microphone 120. Therefore, placing the sound input end above the housing 101 can reduce the impact of the sound-gathering effect of the auricle.

[0103] Optionally, a first matching portion is provided on the shell 101, and a second matching portion is provided on the wearing component (ear hook). The first matching portion and the second matching portion are not shown in the figure. The first matching portion and the second matching portion are matched and connected (for example, plugged in, snapped in, etc.) to achieve the connection between the wearing component and the shell 101. The sound inlet 1011 is provided on the shell 101. The height of the first matching portion and / or the second matching portion along the vertical axis direction is higher than the sound input end of the sound inlet 1011. The sound input end of the sound inlet 1011 is located on the side of the first matching portion and / or the second matching portion toward the back of the human brain along the sagittal axis. In this case, when the user wears the earphones, the first matching portion and / or the second matching portion of the shell 10 can be used to block the airflow from the front of the user from entering the sound inlet 1011. In some embodiments, the first matching portion is a protruding structure protruding from a side wall relative to the shell 101, and the protruding structure is provided with a socket at one end facing away from the shell 101. Correspondingly, the second matching portion is the end of the wearing component (eg, ear hook), which can be plugged into the socket of the first matching portion to achieve connection between the wearing component and the housing 101 .

[0104] Optionally, a spacing distance between the sound inlet end of the sound inlet hole 1011 and the first matching portion and / or the second matching portion along the sagittal axis is less than or equal to half of the maximum dimension of the housing 101 along the sagittal axis.

[0105] Optionally, the distance between the sound input end of the sound input hole 1011 and the first matching part 1012 and / or the second matching part along the sagittal axis is less than or equal to 5 mm. This arrangement makes the sound input end of the sound input hole 1011 closer to the first matching part and / or the second matching part. When the user wears the acoustic device, the sound input end of the sound input hole 1011 is located on the side of the first matching part and / or the second matching part toward the back of the human brain along the sagittal axis. The first matching part and / or the second matching part can better block the airflow from the front of the user from entering the sound input hole 1011.

[0106] In some embodiments, a sound guide channel 102 may be further provided between the sound inlet 1011 and the air conduction microphone 120. Considering that the side wall thickness of the shell 101 is relatively small, an effective sound guide channel 102 cannot be formed. If the shell 101 is thickened and the sound guide channel 102 is directly opened on the shell 101, the processing difficulty of the shell 101 will be greatly increased. In some embodiments, the acoustic device may include a support seat 1010, the support seat 1010 is a three-dimensional structure, at least one side of the support seat 1010 is connected to the side of the shell 101, and the sound guide channel 102 is opened inside the support seat 1010. Furthermore, the sound inlet 1011 is opened on the side wall of the shell 101 and is acoustically connected to the sound guide channel 102 of the support seat 1010. In some embodiments, the sound guide channel 102 may be arranged in a curved shape. For example, the sound guide channel 102 may include a plurality of curved structures connected in sequence. In this case, the volume of the support base 1010 can be relatively small, and at the same time, the length of the sound guiding channel 102 can be increased, the speed of the airflow can be slowed down, and the impact of wind noise can be reduced. If the length of the sound guiding channel 102 is too small, the effect of slowing down the airflow speed is not obvious, and if the length of the sound guiding channel 102 is too large, the volume of the support base 1010 will be too large, causing the overall size of the acoustic device to be too large, affecting the user's wearing experience. Based on this, in some embodiments, the length of the sound guiding channel 102 can be set within the range of 3mm-20mm. The length of the sound guiding channel 102 can refer to the length of the sound guiding channel 102 along its extension direction. In this case, the speed of the airflow can be slowed down and the volume of the support base 1010 can be reasonably controlled.

[0107] In some embodiments of the present specification, by setting a sound guide channel 102 between the sound inlet 1011 and the air conduction microphone 120, and setting the sound guide channel to be bent to increase its length, the air flow speed of the shell 10 can be effectively slowed down, thereby reducing wind noise and improving the sound output effect of the acoustic device 100 (headphones).

[0108] FIG10 is a schematic structural diagram of a bone conduction microphone according to some embodiments of this specification.

[0109] Referring to FIG. 10 , in some embodiments, a bone conduction microphone 110 may include a first supporting structure 111 and a vibration pickup unit 112. The vibration pickup unit 112 is located in a cavity within the first supporting structure 111. The vibration pickup unit 112 of the bone conduction microphone 110 may include an elastic element 1121, a mass 1122, and a transducer unit 1123. The mass 1122 is located on the elastic element 1121. The transducer unit 1123 includes a PCB and a diaphragm. The PCB is connected to the inner wall of the first supporting structure 111 via its circumferential side. The first supporting structure 111 vibrates in response to vibrations of the housing or human skin. The elastic element 1121 and mass 1122 of the vibration pickup unit 112 receive the vibrations of the first supporting structure 111, and the transducer unit 1123 converts the vibrations into electrical signals.

[0110] In some embodiments, the elastic element 1121 and the PCB board separate the cavities within the first supporting structure 111 into a first cavity 113, a second cavity 114, and a third cavity 115. The first supporting structure 111 vibrates (e.g., moves in the up and down directions shown in FIG10 ) in response to vibrations of the housing or human skin. At this time, the elastic element 1121 and the mass block 1122 in the front cavity 113 move relative to the first supporting structure 111, causing the pressure inside the second cavity 114 to change, which in turn causes the diaphragm of the transducer unit 1123 to vibrate. The transducer unit 1123 converts the diaphragm vibration into an electrical signal.

[0111] In some embodiments, the first supporting structure 111 can be a closed structure, meaning that the cavity within the first supporting structure 111 does not have an opening that communicates with the outside world. By making the first supporting structure a closed structure, external air turbulence cannot enter the interior of the first supporting structure 111, thereby significantly reducing the impact of air-conducted sound and wind noise on the bone conduction microphone 110, particularly the pickup unit 112.

[0112] It should be noted that the bone conduction microphone 110 may also be the bone conduction microphones 110A, 110B, and 110C shown in Figures 3 to 5 , and the aforementioned laminated structure may replace the vibration pickup unit 112 in Figure 10 . Furthermore, in some embodiments, the first supporting structure 111 may be a housing structure independent of the housing of the acoustic device; that is, the first supporting structure 111 may be disposed on the housing of the acoustic device. In other embodiments of this specification, the first supporting structure 111 may be omitted, and the vibration pickup unit or laminated structure may be disposed directly within the housing of the acoustic device.

[0113] FIG11 is a schematic diagram of the structure of an air conduction microphone provided according to some embodiments of the present disclosure. As shown in FIG11 , in some embodiments, the air conduction microphone 120 may include a second supporting structure 1210 and a diaphragm 1240. The diaphragm 1240 is located within the cavity of the second supporting structure 1210 and divides the cavity into a front cavity 1220 and a rear cavity 1230. The second supporting structure 1210 is provided with a hole 1250 for connecting the front cavity 1220 with the external environment. External sound can enter the interior of the second supporting structure 1210 through the hole 1250, causing the pressure within the front cavity 1220 to change. The diaphragm 1240 vibrates based on this pressure change, and the transducer unit within the air conduction microphone 120 converts the diaphragm vibration into an electrical signal. It should be noted that the air conduction microphone 120 can be disposed together with the bone conduction transducer and the air conduction transducer in the same supporting structure, such as the housing of an acoustic device. In this case, the second supporting structure is the housing of the acoustic device. In some embodiments, the second supporting structure may also be a structure independent of the shell of the acoustic device, and the second supporting structure may be located outside or inside the shell.

[0114] Compared to the bone conduction microphone 110, the air conduction microphone 120 typically has only one opening in its cavity that communicates with the outside world. This ensures a sound pressure difference between the front cavity 1220 and the rear cavity 1230 of the air conduction microphone 120, thereby increasing sensitivity to air-conducted sound. The above structural distinction between the bone conduction microphone 110 and the air conduction microphone 120 is described. In some embodiments, the distinction between bone conduction microphones and air conduction microphones can also be made based on the microphone's effective operating frequency. For example, the effective operating frequency of a conventional bone conduction microphone is generally within 10 kHz. More specifically, the effective operating frequency of a conventional microphone is generally within the range of 35 kHz to 5 kHz. Correspondingly, the effective operating frequency of an air conduction microphone is wider than that of a bone conduction microphone, for example, the effective operating frequency of an air conduction microphone can generally reach 20 kHz.

[0115] FIG12 is a schematic diagram of the structure of an acoustic device provided according to some embodiments of this specification. As shown in FIG12 , the acoustic device 100 may include a housing 101, a bone conduction microphone 110, at least one air conduction microphone 120, a processing module 130, a bone conduction transducer 140, and an air conduction transducer 150. The bone conduction microphone 110, at least one air conduction microphone 120, the processing module 130, the bone conduction transducer 140, and the air conduction transducer 150 are integrated into the internal cavity of the housing 101. When a user wears the acoustic device 100, one side of the housing 101 is intended to contact the user's face. The bone conduction microphone 110 may be positioned outside the face-facing side of the housing 101 to ensure more complete contact with the user's face, thereby better collecting the first sound pickup signal when the user speaks. In other alternative embodiments, the bone conduction microphone 110 may be positioned inside the face-facing side of the housing 101, so that the face-facing side of the housing 101 can transmit vibrations to the bone conduction microphone 110. At the same time, the air conduction microphone 120 collects a second sound pickup signal transmitted by air conduction through the sound inlet provided in the housing. The bone conduction microphone 110 and the air conduction microphone 120 each collect the user's voice. Processing module 130 performs signal processing to obtain the low-frequency components of the first sound pickup signal and the high-frequency components of the second sound pickup signal, respectively. These components are synthesized into the user's speech signal, reducing the impact of wind noise while improving the quality of the sound signals collected by acoustic device 100 across different frequency bands.

[0116] In some embodiments, the mechanical vibrations generated by the bone conduction vibrator 140, driven by the first sound signal, can be transmitted to the user's face via the face-facing side of the housing 101 and then to the user's auditory nerve via bone conduction through the user's facial muscles, blood, bones, and the like. Driven by the second sound signal, the air conduction vibrator 150 generates air-conducted sound, which is transmitted to the user's eardrum via air conduction through the sound outlet openings in the housing 101. The acoustic device 100 can output bone-conducted sound via the bone conduction vibrator 140. However, the vibrations generated by the bone conduction vibrator 140 will inevitably be received by the bone conduction microphone 110, causing the sound output by the acoustic device 100 to have an echo. In some embodiments, the sum of the second crossover frequency point is greater than the first crossover frequency point, allowing the bone conduction vibrator 140 to output bone-conducted sound above the second crossover frequency point, avoiding the frequency range where the low-frequency components primarily picked up by the bone conduction microphone 110 reside, thereby effectively preventing the bone conduction vibrator 140 from affecting the bone conduction microphone 110. At the same time, since the air conduction sound waves have little effect on the bone conduction microphone 110, the air conduction vibrator 150 outputs the electrical signal containing sound information below the second crossover point as air conduction sound, which can ensure that the user can still hear the sound below the second crossover point.

[0117] It is understood that in some other embodiments of the present application, the acoustic device of the present application can also optimize the working state of the acoustic device. Specifically, the bone conduction vibrator 140 can also generate vibrations in response to an audio signal, and the vibrations can be transmitted to the user wearing the acoustic device through bone conduction. Since the skin load at different positions on the human body is different, the vibration of the bone conduction vibrator 140 is related to the actual wearing position of the user. Here, at least one bone conduction microphone can obtain the vibration signal after the housing of the acoustic device is coupled with the human skin. Furthermore, based on the audio signal and the vibration signal, the vibration response characteristics of the acoustic device (for example, one or more of the resonant frequency, the corresponding peak value of a specific frequency, the quality factor, the input voltage, etc.) can be determined. Based on the vibration response characteristics of the housing of the acoustic device, the working state of the acoustic device can be fed back to optimize the working state of the acoustic device. In some embodiments, the feedback on the working state of the acoustic device may include: when the user is not wearing the acoustic device, generating an instruction to pause the playback of the acoustic device or adaptively adjust the power consumption of the acoustic device to reduce the power consumption of the acoustic device. In some embodiments, providing feedback on the operating status of the acoustic device may include: when the acoustic device is not properly worn, generating a prompt message prompting the user to put the acoustic device on again, so that the sound quality heard by the user through the acoustic device is improved, thereby obtaining a better listening experience. In some embodiments, providing feedback on the operating status of the acoustic device may include: when the input voltage of the acoustic device is too low or too high, adaptively adjusting the amplitude of the audio signal input to the acoustic device to ensure that the user can hear the sound at an appropriate volume. In some embodiments, providing feedback on the operating status of the acoustic device may include: when the clamping force when the user wears the acoustic device is too low or too high, adaptively adjusting the clamping force when the user wears the acoustic device to ensure the transmission efficiency of bone conduction while ensuring the user's wearing comfort. In some embodiments, providing feedback on the operating status of the acoustic device may also include: when different users wear the acoustic device or when the same user wears the acoustic device repeatedly, performing EQ compensation on the audio signal input to the acoustic device to ensure that the sound effect heard by different users or users using different wearing methods through the acoustic device is the same. In some embodiments, the user's physiological state can be monitored by providing feedback on the working state of the acoustic device, so as to supervise and provide feedback on the user's health condition.

[0118] While the basic concepts have been described above, it will be apparent to those skilled in the art that the detailed disclosure is merely illustrative and does not limit this specification. Although not explicitly stated herein, various modifications, improvements, and revisions to this specification may be made by those skilled in the art. Such modifications, improvements, and revisions are suggested in this specification and remain within the spirit and scope of the exemplary embodiments of this specification.

Claims

1. An acoustic device, characterized in that: include: A bone conduction microphone, which picks up vibrations when the user speaks to generate a first sound pickup signal; At least one air conduction microphone, picking up the air conduction sound of the user speaking to generate a second sound pickup signal; as well as A processing module, which synthesizes a voice signal reflecting the user's speech content according to the low-frequency components in the first sound pickup signal and the high-frequency components in the second sound pickup signal; The frequency corresponding to the low-frequency component is below a first crossover point, the frequency corresponding to the high-frequency component is above the first crossover point, and the resonant frequency of the bone conduction microphone is higher than the first crossover point.

2. The acoustic device according to claim 1, characterized in that The first crossover frequency point is in the range of 500 Hz-1000 Hz.

3. The acoustic device according to claim 2, characterized in that The difference between the resonant frequency of the bone conduction microphone and the first frequency division point is not less than 500 Hz.

4. The acoustic device according to claim 1, characterized in that The acoustic device also includes a bone conduction vibrator and an air conduction vibrator. The bone conduction vibrator outputs bone conduction sound when driven by a first sound signal, and the air conduction vibrator outputs air conduction sound when driven by a second sound signal. The first sound signal includes a component greater than a second crossover frequency point, the second sound signal includes a component less than the second crossover frequency point, and the first crossover frequency point is less than the second crossover frequency point.

5. The acoustic device according to claim 4, characterized in that The second crossover frequency point is not less than 1000 Hz.

6. The acoustic device according to claim 5, characterized in that The second crossover frequency point is in the range of 1000 Hz-2500 Hz.

7. The acoustic device according to claim 4, characterized in that The difference between the second frequency division point and the first frequency division point is in the range of 100 Hz-2000 Hz.

8. The acoustic device according to claim 4, characterized in that The ratio of the first frequency division point to the second frequency division point is in the range of 0.2-1.

9. The acoustic device according to claim 4, characterized in that The acoustic device comprises a housing, and the bone conduction microphone is arranged at a side of the housing for contacting human skin.

10. The acoustic device according to claim 4, characterized in that The angle between the vibration direction of the bone conduction microphone and the vibration direction of the bone conduction vibrator is no greater than 25°.

11. The acoustic device according to claim 1, characterized in that The at least one air conduction microphone includes a first air conduction microphone and a second air conduction microphone. When the user wears the acoustic device, a line connecting the first air conduction microphone and the second air conduction microphone points to the user's mouth area.

12. The acoustic device according to claim 11, characterized in that The distance between the first air conduction microphone and the second air conduction microphone is in the range of 10 mm-50 mm.

13. The acoustic device according to claim 11, characterized in that In the wearing state, one of the first air conduction microphone and the second air conduction microphone is arranged in a low flow velocity area on a side of the acoustic device facing the back of the user's head.

14. The acoustic device according to claim 13, characterized in that The processing module is further configured to: Determining whether the user is in a wind noise state based on the external sound signals respectively collected by the first air conduction microphone and the second air conduction microphone; If the user is in a wind noise state, controlling one of the first air conduction microphone and the second air conduction microphone that is set in a low flow rate area to collect a sound signal when the user is speaking; If the user is not in a wind noise state, one of the first air conduction microphone and the second air conduction microphone that is closer to the user's mouth is controlled to collect a sound signal when the user is speaking.

15. The acoustic device according to claim 14, characterized in that The determining whether the user is in a wind noise state based on the external sound signals respectively collected by the first air conduction microphone and the second air conduction microphone includes: Determine whether the correlation between the external sound signals picked up by the first air conduction microphone and the second air conduction microphone is greater than a correlation threshold; If the correlation is greater than the correlation threshold, the user is not in a wind noise state; If the correlation is less than the correlation threshold, the user is in a wind noise state.

16. The acoustic device according to claim 1, characterized in that The bone conduction microphone includes a first bearing structure and a vibration pickup unit, wherein the vibration pickup unit is located in a cavity inside the first bearing structure. The vibration pickup unit of the bone conduction microphone includes an elastic element and a mass block, wherein the mass block is located on the elastic element. The first bearing structure vibrates in response to the vibration of the shell or human skin, and the vibration pickup unit receives the vibration of the first bearing structure and converts the vibration into an electrical signal.

17. The acoustic device according to claim 1, characterized in that The bone conduction microphone comprises a first bearing structure and a vibration pickup unit. The vibration pickup unit is located in a cavity inside the first bearing structure. The first bearing structure is a closed structure.

18. The acoustic device according to claim 1, characterized in that The air conduction microphone includes a second bearing structure and a diaphragm. The diaphragm is located in the cavity of the second bearing structure and divides the cavity into a front cavity and a rear cavity. The bearing structure is provided with a hole for connecting the front cavity with the external environment.

19. The acoustic device according to any one of claims 1 to 18, characterized in that: The processing module is further configured to: Acquiring a vibration signal through the bone conduction microphone, wherein the vibration signal is at least partially derived from vibration of the housing of the acoustic device in response to an audio signal, and the housing vibration of the acoustic device is configured to be transmitted to a user wearing the acoustic device in a bone conduction manner; determining a vibration response characteristic of the housing based on the vibration signal and the audio signal; as well as Based on the vibration response characteristics of the shell, the working state of the acoustic device is fed back.

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