Ambient sound enhancing structure and acoustic device

Abstract

The invention provides an ambient sound enhancement structure and an acoustic device. The enhancement structure comprises a shell, a resonance tube and a radio microphone. The shell comprises a sound receiving hole used for receiving external environment sound and a sound receiving cavity formed in the shell. The resonance tube is arranged in the shell and is communicated with the sound receiving hole and the sound receiving cavity, and the resonance tube is arranged to be capable of resonating at a preset frequency point. And a vibrating diaphragm of the radio microphone faces the radio cavity. According to the scheme, the transparent mode effect can be improved, and the transparent performance is improved.

Description

Technical Field

[0001] The present application relates to the field of acoustic technology, and in particular, to an ambient sound enhancement structure and an acoustic device. Background Art

[0002] Taking headphones as an example, when people wear headphones, the wearer cannot hear the outside sounds clearly. In the transparency mode, the headphones can pick up the outside sounds through the microphone, process the sounds, and then play them through the speakers of the headphones. This can offset the isolation effect of the headphones on the outside sounds to a certain extent, allowing the wearer to hear the outside sounds more clearly. The more the sound isolation effect is offset, the better the transparency performance.

[0003] Existing solutions for implementing transparent technology are mainly based on DSP chip filters that process the external and ear sounds picked up by the microphone, and then output them to the speaker to produce sounds that offset the sound insulation effect of the headphones. Some existing technologies use low-noise digital microphones, chips, digital-to-analog conversion, multi-channel technology, and circuit noise isolation technology to reduce battery and RF noise to improve the signal-to-noise ratio in exchange for more gain increase margin, thereby improving transparent performance. Other existing technologies use WDRC (wide dynamic range compression) technology to increase the gain of certain frequency bands that are sensitive to the human ear, while only amplifying the background noise in narrow frequency bands, and are more commonly used in the field of auxiliary listening and hearing aids. Summary of the invention

[0004] The present application provides an ambient sound enhancement structure and an acoustic device, which can improve the transparency mode effect and enhance the transparency performance.

[0005] An environmental sound enhancement structure, comprising:

[0006] The housing comprises a sound receiving hole for receiving external ambient sound and a sound receiving cavity formed inside the housing;

[0007] A resonance tube is disposed in the housing and communicates with the sound receiving hole and the sound receiving cavity, and the resonance tube is configured to resonate at a preset frequency point; and

[0008] A sound receiving microphone, wherein the diaphragm of the sound receiving microphone faces the sound receiving cavity.

[0009] Optionally, the length l and the diameter d of the resonance tube are based on Sure;

[0010] Among them, f0 is the frequency point at which the resonance tube produces resonance, c is the speed of sound, l is the length of the resonance tube, d is the diameter of the resonance tube, S is the cross-sectional area of ​​the resonance tube, V is the volume of the sound receiving cavity, and a and b are constants.

[0011] Optionally, the resonance tube is configured as a variable cross-section tube.

[0012] Optionally, the resonance tube is configured as a straight tube or a curved tube connecting the sound receiving hole and the sound receiving cavity, and along the resonance tube and in the direction from the sound receiving hole to the sound receiving cavity, the cross-sectional area of ​​the resonance tube changes from large to small and transitions smoothly.

[0013] Optionally, the length of the resonance tube is greater than the straight-line distance between the sound receiving hole and the sound receiving cavity.

[0014] Optionally, the resonance tube comprises an arc-shaped curved tube with a smooth transition, and an arc-shaped channel for the resonance tube to pass through is provided in the shell, and the resonance tube remains relatively fixed with the shell in the arc-shaped channel.

[0015] Optionally, the resonance tube includes a first tube and a second tube that are relatively bent, the first tube and the second tube are both configured as straight tubes, the first tube and the second tube are configured at an angle, the first tube and the second tube are connected end to end and have a smooth transition at the connection.

[0016] Optionally, one end of the resonance tube communicating with the sound receiving hole is provided with a first acoustic resistance structural member for increasing acoustic resistance; and / or

[0017] One end of the resonance tube communicating with the sound receiving cavity is provided with a second acoustic resistance structural member for increasing acoustic resistance.

[0018] Optionally, the quality factor Q of the ambient sound enhancement structure is equal to f0 / W, and the quality factor Q is negatively correlated with the acoustic impedance, wherein f0 is the frequency point at which the resonance tube resonates, and W is the bandwidth;

[0019] The volume of the sound receiving cavity is determined according to the expected f0 and the inner size of the shell, the length and diameter of the resonance tube are determined according to the volume of the sound receiving cavity and the expected f0, and the bandwidth W is determined according to the acoustic impedance.

[0020] Optionally, the inner surface of the sound receiving cavity is a hemispherical surface, a cylindrical surface or a pancake-shaped surface.

[0021] Optionally, the housing further comprises a sound outlet hole for emitting sound, and the direction of the sound receiving hole is opposite to the direction of the sound outlet hole.

[0022] An acoustic device comprises any one of the above-mentioned environmental sound enhancement structures.

[0023] The present application provides an environmental sound enhancement structure and an acoustic device, wherein a resonance tube connects a sound receiving hole and a sound receiving cavity. When external environmental sound enters the sound receiving hole and is transmitted to the sound receiving cavity, resonance can be generated through the resonance tube within a preset frequency band. When the background noise and gain do not change, the signal-to-noise ratio near this frequency point increases, thereby increasing the gain of the sound pickup, thereby increasing the transparency and improving the transparency effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 is a schematic diagram of an ambient sound enhancement structure shown in an exemplary embodiment of the present application;

[0025] Figure 2 is another schematic diagram of an ambient sound enhancement structure shown in an exemplary embodiment of the present application;

[0026] Figure 3 is another schematic diagram of an ambient sound enhancement structure shown in an exemplary embodiment of the present application;

[0027] Figure 4 is another schematic diagram of an ambient sound enhancement structure shown in an exemplary embodiment of the present application;

[0028] Figure 5 It is a schematic diagram of the improvement of signal-to-noise ratio gain. DETAILED DESCRIPTION

[0029] Here, exemplary embodiments will be described in detail, and examples thereof are shown in the accompanying drawings. When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present application. Instead, they are only examples of devices and methods consistent with some aspects of the present application.

[0030] The terms used in this application are only for the purpose of describing specific embodiments, and are not intended to limit this application. Unless otherwise defined, the technical terms or scientific terms used in this application should be understood by people with ordinary skills in the field to which this application belongs. The "first", "second" and similar words used in this application do not indicate any order, quantity or importance, but are only used to distinguish different components. Similarly, similar words such as "one" or "one" do not indicate quantity restrictions, but indicate that there is at least one, and will be separately described if only "one" is referred to. "Multiple" or "several" means two or more. Unless otherwise specified, similar words such as "front", "rear", "lower" and / or "upper", "top", "bottom" are only for the convenience of explanation, and are not limited to one position or one spatial orientation. Similar words such as "include" or "comprise" mean that the elements or objects appearing in front of "include" or "comprise" cover the elements or objects listed after "include" or "comprise" and their equivalents, and do not exclude other elements or objects. The words "connected" or "connected" and the like are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect.

[0031] Please refer to Figure 1 , Figure 1 It is a schematic diagram of an ambient sound enhancement structure 100 shown in an exemplary embodiment of the present application.

[0032] The present application provides an ambient sound enhancement structure 100 , which includes a housing 10 , a resonance tube 20 and a sound pickup microphone 30 .

[0033] The housing 10 includes a sound receiving hole 11 for receiving external ambient sound and a sound receiving cavity 12 formed inside the housing 10. A resonance tube 20 is disposed inside the housing 10, connecting the sound receiving hole 11 and the sound receiving cavity 12, and the resonance tube 20 is configured to generate resonance within a preset frequency band. A sound receiving microphone 30 is disposed on a circuit board, and includes a diaphragm 31 for receiving sound, and the diaphragm 31 faces the sound receiving cavity 12. The inner surface of the resonance tube 20 and the inner surface of the sound receiving cavity 12 are both smooth transition surfaces.

[0034] According to the above description, when the external ambient sound enters from the sound receiving hole 11 and is transmitted to the sound receiving cavity 12, resonance can be generated through the resonance tube 20 within the preset frequency band. When the background noise and gain do not change, the signal-to-noise ratio near this frequency point increases, thereby increasing the gain of the sound pickup, thereby increasing the permeability and improving the permeability effect.

[0035] In one embodiment, the length l and the diameter d of the resonance tube 20 can be Wherein, f0 is the frequency point at which the resonance tube 20 generates resonance, c is the speed of sound, l is the length of the resonance tube 20, d is the diameter of the resonance tube 20, S is the cross-sectional area of ​​the resonance tube 20, V is the volume of the sound receiving cavity 12, a and b are constants, a=0.8, b=2π.

[0036] In actual application scenarios, the design target f0 can be determined first. For example, if you need to increase the gain of external ambient sound in the frequency band around 5000Hz, you can design f0 to be around 10000Hz. In order to increase the gain and avoid pickup distortion at f0, you need to determine the quality factor Q, Q = f0 / W, W is the bandwidth. If you want to use the resonance of 10000Hz to increase the gain of 5000Hz, Q should be less than 1. For example, you can adjust the Q value by adjusting the acoustic impedance, and then adjust the resonance tube 20 to increase the gain range.

[0037] Secondly, the volume V of the sound receiving cavity 12 is determined according to f0, and the volume V of the sound receiving cavity 12 can be set according to the structure of the housing 10.

[0038] Finally, the length l and the diameter d of the resonance tube 20 are determined according to the volume V of the sound receiving cavity 12. For example, the length l and the diameter d of the resonance tube 20 can be fine-tuned through experiments or simulations.

[0039] Please refer to Figure 2 , Figure 2 This is another schematic diagram of an ambient sound enhancement structure 100 according to an exemplary embodiment of the present application.

[0040] In one embodiment, the resonance tube 20 is configured as a variable cross-section tube. That is, the resonance tube 20 is not limited to a tube body with a constant cross-section, but can also be a tube body with a variable cross-section. For the resonance tube 20 with a variable cross-section, the cross-sectional areas at various parts of the resonance tube 20 are not completely equal, but vary in size. In this way, the range of the resonance point of the resonance tube 20 can be widened, so that the resonance tube 20 resonates around the resonance point.

[0041] exist Figure 2 In the illustrated embodiment, the resonance tube 20 is configured as a straight tube connecting the sound receiving hole 11 and the sound receiving cavity 12. Along the resonance tube 20 and in the straight line direction from the sound receiving hole 11 to the sound receiving cavity 12, the cross-sectional area of ​​the resonance tube 20 changes from large to small and transitions smoothly. In other words, the resonance tube 20 has a conical structure, and the cross-sectional area of ​​the resonance tube 20 increases gradually and smoothly, which can facilitate the manufacture of the resonance tube 20. The "smooth" mentioned here means that there is no sudden change on the inner surface of the resonance tube 20. Unless otherwise specified, the "smooth" that appears below has the same meaning.

[0042] In some other embodiments, the resonance tube 20 may also be configured as a curved tube connecting the sound receiving hole 11 and the sound receiving cavity 12, and the cross-sectional area of ​​the resonance tube 20 changes from large to small and transitions smoothly along the curved direction of the resonance tube 20 from the sound receiving hole 11 to the sound receiving cavity 12. Compared with a straight tube, this can increase the length of the resonance tube 20, and further adjust the resonance point of the resonance tube 20.

[0043] Please refer to Figure 3 and Figure 4 , Figure 3 This is another schematic diagram of an ambient sound enhancement structure 100 according to an exemplary embodiment of the present application. Figure 4 This is another schematic diagram of an ambient sound enhancement structure 100 according to an exemplary embodiment of the present application.

[0044] exist Figure 3 and Figure 4 In the illustrated embodiment, the length of the resonance tube 20 is greater than the straight-line distance between the sound receiving hole 11 and the sound receiving cavity 12. In this way, the length of the resonance tube 20 can be increased and the resonance point of the resonance tube 20 can be adjusted.

[0045] exist Figure 3 In the embodiment shown, the resonance tube 20 is configured as an arc-shaped curved tube with a smooth transition. Accordingly, the housing 10 is provided with an arc-shaped channel (not shown) for the resonance tube 20 to pass through, and the resonance tube 20 is relatively fixed to the housing 10 in the arc-shaped channel. In this configuration, the arc-shaped curved tube can not only increase the length of the resonance tube 20, but also avoid the appearance of sharp corners at the inner wall corners of the resonance tube 20. The size of the resonance tube 20 can be determined according to the size of the housing 10, and the fixing method of the housing 10 and the resonance tube 20 is not limited.

[0046] exist Figure 4 In the illustrated embodiment, the resonance tube 20 includes a first tube 21 and a second tube 22 that are relatively bent, the first tube 21 and the second tube 22 are both set as straight tubes, the first tube 21 and the second tube 22 are set at an angle, the first tube 21 and the second tube 22 are connected end to end and have a smooth transition at the connection. In this way, not only can the length of the resonance tube 20 be increased, but also sharp corners can be avoided at the corners of the resonance tube 20. It should be noted that the length of the resonance tube 20 cannot be increased at will. When the length of the resonance tube 20 is increased, it will also hinder the radio microphone 30 from receiving sound, and fine-tuning and verification are required during the design process.

[0047] In one embodiment, one end of the resonance tube 20 connected to the sound receiving hole 11 is provided with a first acoustic resistance structure for increasing the sound propagation resistance, and the first acoustic resistance structure includes but is not limited to an acoustic resistance mesh. In another embodiment, one end of the resonance tube 20 connected to the sound receiving cavity 12 is provided with a second acoustic resistance structure for increasing the sound propagation resistance, and the second acoustic resistance structure includes but is not limited to an acoustic resistance mesh. The first acoustic resistance mesh and / or the second acoustic resistance mesh can change the quality factor Q value by changing the acoustic resistance, and the quality factor Q value is negatively correlated with the acoustic resistance, that is, increasing the acoustic resistance can reduce the Q value. In actual application scenarios, the volume of the sound receiving cavity 12 is determined according to the expected f0 and the internal dimensions of the housing 10, the length and diameter of the resonance tube 20 are determined according to the volume of the sound receiving cavity 12 and the expected f0, and the bandwidth W is determined according to the acoustic resistance. Changing the acoustic resistance will not change f0, but only affect the bandwidth W, but the length is limited, as a fine-tuning method to adjust the gain range affected by the resonance tube 20. This application does not limit the internal shape of the sound receiving cavity 12. In one embodiment, the inner surface of the sound receiving cavity 12 includes but is not limited to a hemispherical surface, a cylindrical surface or a pancake surface, wherein the inner surface of the sound receiving cavity 12 is a smooth transition surface to avoid sharp corners.

[0048] In one embodiment, the housing 10 further includes a sound outlet (not shown) for emitting sound, and the sound receiving hole 11 is oriented opposite to the sound outlet. In actual application scenarios, the sound outlet faces the user's ear, and the sound receiving hole 11 is arranged opposite to the sound outlet, which can reduce or prevent the sound emitted by the user from entering the sound receiving hole 11, thereby reducing interference with external ambient sound.

[0049] Please refer to Figure 5 , Figure 5 It is a schematic diagram of the improvement of signal-to-noise ratio gain.

[0050] Depend on Figure 5 It can be seen that by providing the resonance tube 20, the pickup gain of the radio microphone 30 is no longer a straight curve, but has an upward trend in the part where the gain needs to be increased. Figure 5 In the curve shown, resonance occurs at a frequency of about 5000Hz, the gain is increased, the signal-to-noise ratio is improved, and the transparency is improved.

[0051] According to the principle of improving the signal-to-noise ratio, the frequency response curve of the radio microphone 30 receiving external sounds is usually a flat curve in the range of 20Hz to 10000Hz. This means that, assuming that there are three single-frequency sounds in the outside world, 200Hz, 90dB, 1000Hz, 90dB, and 4000Hz, 90dB, the sounds actually received by the radio microphone and transmitted to the next level are also 200Hz, 90dB, 1000Hz, 90dB, 4000Hz, 90dB. When the gain of the entire system remains unchanged and the background noise remains unchanged, the so-called signal-to-noise ratio is a relatively constant value at each frequency. When a resonance point is given by the resonance tube 20, the sound received around this point is larger than the actual one. For example, the f0 of the resonance tube is designed to be 4000Hz. Assuming there are three single-frequency sounds, (200Hz, 90dB), (1000Hz, 90dB), (4000Hz, 90dB), the sound actually received by the microphone 30 and transmitted to the next level is (200Hz, 90dB), (1000Hz, 90dB), (4000Hz, 90+dB). In this way, the actual sound received at 4000Hz becomes louder, but the background noise and gain do not change, and the signal-to-noise ratio near this frequency point is actually increased. The "90+dB" mentioned here means greater than 90dB.

[0052] The present application also provides an acoustic device, which includes but is not limited to AR glasses, VR glasses, hearing aids, and headphones. The headphones can be TWS (True Wireless Stereo) headphones or headphones.

[0053] In one embodiment, the acoustic device further includes a DAC module, a DSP chip, an ADC module, and a speaker. The radio microphone 30 is connected to the DAC module. After the radio microphone 30 picks up the external ambient sound, it is converted into an electrical signal, which passes through the DAC module, the DSP chip, the ADC module, and the speaker in sequence, and sounds through the speaker. The whole process will introduce noise from the hardware circuit before reaching the speaker. For example, a hardware circuit system with low background noise can be used, thereby introducing lower background noise.

[0054] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application shall be included in the scope of protection of the present application.

Claims

1. An ambient sound enhancement structure, characterized in that: include: The housing comprises a sound receiving hole for receiving external ambient sound and a sound receiving cavity formed inside the housing; A resonance tube is disposed in the housing and communicates with the sound receiving hole and the sound receiving cavity, and the resonance tube is configured to resonate at a preset frequency point; and A sound receiving microphone, wherein the diaphragm of the sound receiving microphone faces the sound receiving cavity.

2. The environmental sound enhancement structure according to claim 1, characterized in that: The length l and diameter d of the resonance tube are based on Sure; Among them, f0 is the frequency point at which the resonance tube produces resonance, c is the speed of sound, l is the length of the resonance tube, d is the diameter of the resonance tube, S is the cross-sectional area of ​​the resonance tube, V is the volume of the sound receiving cavity, and a and b are constants.

3. The environmental sound enhancement structure according to claim 1 or 2, characterized in that: The resonance tube is configured as a variable cross-section tube.

4. The environmental sound enhancement structure according to claim 3, characterized in that: The resonance tube is configured as a straight tube or a curved tube connecting the sound receiving hole and the sound receiving cavity. Along the resonance tube and in the direction from the sound receiving hole to the sound receiving cavity, the cross-sectional area of ​​the resonance tube changes from large to small and transitions smoothly.

5. The environmental sound enhancement structure according to claim 1 or 2, characterized in that: The length of the resonance tube is greater than the straight-line distance between the sound receiving hole and the sound receiving cavity.

6. The environmental sound enhancement structure according to claim 5, characterized in that: The resonance tube comprises an arc-shaped curved tube with a smooth transition. The shell is provided with an arc-shaped channel for the resonance tube to pass through. The resonance tube is relatively fixed with the shell in the arc-shaped channel.

7. The environmental sound enhancement structure according to claim 5, characterized in that: The resonance tube comprises a first tube and a second tube that are bent relatively, the first tube and the second tube are both set as straight tubes, the first tube and the second tube are set at an angle, the first tube and the second tube are connected end to end and have a smooth transition at the connection.

8. The environmental sound enhancement structure according to claim 1 or 2, characterized in that: One end of the resonance tube communicating with the sound receiving hole is provided with a first acoustic resistance structural member for increasing acoustic resistance; and / or One end of the resonance tube communicating with the sound receiving cavity is provided with a second acoustic resistance structural member for increasing acoustic resistance.

9. The environmental sound enhancement structure according to claim 8, characterized in that: The quality factor Q of the environmental sound enhancement structure is f0 / W, and the quality factor Q is negatively correlated with the acoustic impedance, wherein f0 is the frequency point at which the resonance tube resonates, and W is the bandwidth; The volume of the sound receiving cavity is determined according to the expected f0 and the inner size of the shell, the length and diameter of the resonance tube are determined according to the volume of the sound receiving cavity and the expected f0, and the bandwidth W is determined according to the acoustic impedance.

10. The environmental sound enhancement structure according to claim 1 or 2, characterized in that: The inner surface of the sound receiving cavity is a hemispherical surface, a cylindrical surface or a pancake surface; and / or The housing further comprises a sound outlet hole for emitting sound, and the direction of the sound receiving hole is opposite to the direction of the sound outlet hole.

11. An acoustic device, characterized in that: It comprises the environmental sound enhancement structure as described in any one of claims 1 to 10.

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