Acoustic parameter measuring equipment and acoustic material measuring equipment

Abstract

This invention discloses an acoustic parameter measuring device and an acoustic material measuring device. A detection tube and a first sound-emitting module disposed at a first opening of the detection tube can be repeatedly used in both the acoustic parameter measuring device and the acoustic material measuring device. Different measuring devices can be formed by replacing the module connected to a second opening of the detection tube. Setting the first detection module at the second opening constitutes an acoustic parameter measuring device for measuring the acoustic parameters of a microphone under test; setting the second sound-emitting module at the second opening constitutes an acoustic material measuring device for measuring the acoustic parameters of an acoustic material under test. This invention, by providing a structure with a detection tube and a first sound-emitting module, allows for different acoustic measurements to be performed on various products under test by changing some modules.

Description

[Technical Field]

[0001] This invention relates to the field of acoustic technology, specifically to acoustic parameter measuring equipment and acoustic material measuring equipment. [Previous Technology]

[0002] Acoustic testing is a non-contact measurement technique that extracts information about the properties, structure, or other characteristics of an object by emitting sound wave signals and analyzing the reflected sound waves or calculating the sound waves received by the object under test. This method can be applied in many fields, including engineering, medicine, and environmental science. Depending on the properties of the object under test and the items to be tested, the acoustic testing of different objects often has different requirements, necessitating the setup of different test conditions and the configuration of different test instruments. It is difficult to conveniently measure the different acoustic parameters of various objects under test in a small environment. [Summary of the Invention]

[0003] In view of this, the purpose of the present invention is to provide an acoustic parameter measuring device and an acoustic material measuring device to improve the convenience of performing different acoustic tests on different objects to be tested.

[0004] In a first aspect, embodiments of the present invention provide an acoustic parameter measuring device, comprising: a detection tube having a sidewall, at least one detection hole being provided on the sidewall, and a first opening and a second opening being respectively provided at opposite ends along an axis; a first sound-emitting module being disposed at the first opening, the first sound-emitting module having a first loudspeaker; and a second sound-emitting module being detachably connected to the second opening, the second sound-emitting module having a second loudspeaker; and a control circuit, the first loudspeaker and the second loudspeaker being electrically connected to the control circuit; wherein the control circuit is electrically connected to a reference microphone, and the detection tube is configured to allow the microphone under test to pass through and extend into the detection hole.

[0005] Further, the acoustic parameter measuring device also includes a control circuit, which is configured to send a first detection signal to the first speaker to cause the first speaker to emit a first detection sound signal, and send a first cancellation signal to the second speaker to cause the second speaker to emit a first cancellation sound signal; the control circuit is also configured to send a second detection signal to the second speaker to cause the second speaker to emit a second detection sound signal, and send a second cancellation signal to the first speaker to cause the first speaker to emit a second cancellation sound signal.

[0006] Further, the control circuit includes a signal delay device, which is a first filter or a delay component.

[0007] Further, the first detection sound signal and the first cancellation sound signal are superimposed to form a first reference signal, and the second detection sound signal and the second cancellation sound signal are superimposed to form a second reference signal; the reference microphone collects the first reference signal and the second reference signal, the control circuit generates the first cancellation signal according to the first reference signal, and the control circuit generates the second cancellation signal according to the second reference signal.

[0008] Further, the reference microphone includes a first reference microphone and a second reference microphone. The first reference microphone is positioned close to the first sound-emitting module and receives the second reference signal, and the second reference microphone is positioned close to the second sound-emitting module and receives the first reference signal.

[0009] Furthermore, the control circuit also includes a second filter.

[0010] Furthermore, the second filter is a minimum mean square filter.

[0011] Further, when the control circuit sends a first detection signal to the first speaker and a first cancellation signal to the second speaker, the signal delay device is configured to delay the output of the first cancellation signal, and the second filter is configured to correct the first cancellation signal; when the control circuit sends a second detection signal to the second speaker and a second cancellation signal to the first speaker, the signal delay device is configured to delay the output of the second cancellation signal, and the second filter is configured to correct the second cancellation signal.

[0012] Further, the first sound-emitting module also includes a first sound-absorbing material disposed on the side of the first speaker away from the second speaker; and / or the second sound-emitting module also includes a second sound-absorbing material disposed on the side of the second speaker away from the first speaker.

[0013] Further, the distance from at least one detection hole to the first speaker is equal to the distance to the second speaker.

[0014] Furthermore, the inner diameter of the detection tube is 6cm and the length is 50cm.

[0015] In a second aspect, embodiments of the present invention also provide an acoustic material measuring device, the acoustic material measuring device comprising: a detection tube having a sidewall, at least one detection hole being provided on the sidewall, the detection tube having a first opening and a second opening at opposite ends along its axis; a first sound-emitting module disposed at the first opening, the first sound-emitting module having a first loudspeaker; and a first detection module detachably connected to the second opening, the first detection module having a reflective structure, the first detection module being used to contain the acoustic material to be tested.

[0016] Furthermore, the reflective structure is disposed at the second opening and closes the second opening.

[0017] Further, the first loudspeaker generates an initial sound signal, which passes through the acoustic material to be tested, is reflected by the reflective structure, and passes through the acoustic material to be tested again to form a detection sound signal; the acoustic material measuring device also includes a detection microphone, which receives the initial sound signal and the detection sound signal.

[0018] Furthermore, the shape of the detection hole matches the shape of the detection microphone, and the detection microphone is set inside the detection tube through the detection hole.

[0019] Furthermore, the sidewall has multiple detection holes, and the distances from the multiple detection holes to the first opening are all different. The acoustic material measuring device includes two detection microphones, which are respectively set in different detection holes.

[0020] Furthermore, the detection microphone is positioned between the first sound-emitting module and the first detection module.

[0021] Furthermore, the first sound-emitting module also includes a first sound-absorbing material disposed on the side of the first speaker away from the first detection module.

[0022] Furthermore, the inner diameter of the detection tube is 10cm.

[0023] This invention discloses an acoustic parameter measuring device and an acoustic material measuring device. A detection tube and a first sound-emitting module disposed at the first opening of the detection tube can be repeatedly applied to both the acoustic parameter measuring device and the acoustic material measuring device. Different measuring devices can be formed by replacing the module connected to the second opening of the detection tube. Setting the first detection module at the second opening constitutes an acoustic parameter measuring device to measure the acoustic parameters of the microphone under test; setting the second sound-emitting module at the second opening constitutes an acoustic material measuring device to measure the acoustic parameters of the acoustic material under test. This invention, by providing a structure with a detection tube and a first sound-emitting module, allows for different acoustic measurements of various products under test after replacing some modules, reducing the space required for testing, the difficulty of testing, and the cost of testing.

Implementation Method

[0025] The present application is described below based on embodiments, but the present application is not limited to these embodiments. In the following detailed description of the present application, some specific details are described in detail. Those skilled in the art to which this application pertains can fully understand the present application without these details. In order to avoid obscuring the substance of the present application, well-known methods, processes, flows, elements and circuits are not described in detail.

[0026] Furthermore, those skilled in the art to which this application pertains should understand that the drawings provided herein are for illustrative purposes and are not necessarily drawn to scale.

[0027] Unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. For those skilled in the art to which this application pertains, the specific meaning of the above terms in this application can be understood according to the specific circumstances.

[0028] For ease of explanation, spatial terms such as “inner,” “outer,” “below,” “below,” “lower part,” “above,” “upper part,” etc., are used herein to describe the relationship between one element or feature illustrated in the figures and another element or feature. It will be understood that spatial terms may be intended to include different orientations of the device in use or operation other than those depicted in the figures. For example, if the device in the figures is flipped, an element described as “below” or “below” other elements or features would then be positioned “above” those other elements or features. Thus, the illustrative term “below” can include both above and below orientations. The device may be oriented in other ways (rotated 90 degrees or in other orientations), and the spatial descriptive terms used herein should be interpreted accordingly.

[0029] Unless the context explicitly requires it, the words "including" or "contains" in the entire application document should be interpreted as including rather than exclusive or exhaustive; that is, "including but not limited to".

[0030] In the description of this application, it should be understood that the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance. Furthermore, in the description of this application, unless otherwise stated, "a plurality of" means two or more.

[0031] A microphone, also known as a transducer or microphone, is an energy conversion device that converts sound signals into electrical signals. The directivity of a microphone refers to its ability to receive and respond to sound in different directions. It describes the microphone's sensitivity and suppression of sound at different angles and positions. Microphone directivity can be categorized as: unidirectional, bidirectional, and omnidirectional.

[0032] A unidirectional microphone can capture sound from a specific direction, thus playing an important role in providing clear voice input, reducing noise interference, and improving speech recognition. Unidirectional microphones are commonly used in handheld recording devices, microphones, telephones, and communication equipment, and are a very common type of microphone. A bidirectional microphone has two main pickup directions; sound from the front and back can be effectively captured, while sound from the sides is suppressed. Bidirectional microphones can be used for stereo pickup in music recording, with the microphone elements corresponding to the left and right channels respectively, thus achieving a stereo effect. Bidirectional microphones are also commonly used in interviews and conference recordings, where the presenter or interviewer can face the microphone while side noise and other people's voices are suppressed.

[0033] A pressure gradient sensing microphone (also known as a differential pressure microphone) has openings on both the front and back sides of the microphone, allowing sound waves to be transmitted from front to back to the microphone diaphragm. The diaphragm senses the pressure difference caused by the front and rear sound waves on its surface. In this case, the pressure gradient microphone is bidirectional. When the pressure gradient sensing microphone is used in conjunction with an acoustic mesh, it can affect the time difference between the front and rear sound waves when they reach the diaphragm, causing the diaphragm to remain stationary after the sound waves cancel each other out in some directions, and the diaphragm to vibrate more in other directions, thus making the microphone either unidirectional or bidirectional.

[0034] When producing differential pressure microphones, it is necessary to check whether the assembly of the microphones is correct and whether there are any air leaks. During testing, the microphone under test (i.e., the newly produced differential pressure microphone) needs to be placed in a spacious, anechoic environment with sufficient distance between the walls and the microphone. However, the production line for differential pressure microphones does not have such a testing environment, making rapid testing impossible, resulting in reduced production efficiency and product reliability.

[0035] This embodiment of the invention provides an acoustic parameter measuring device for testing the assembly performance of a microphone 51 under test. As shown in Figures 1 and 2, the acoustic parameter measuring device includes a detection tube 1, a first sound-emitting module 2, and a second sound-emitting module 3. The microphone 51 under test is disposed inside the detection tube 1. The detection tube 1 has a first opening 12 and a second opening 13 at opposite ends along its axis. The first sound-emitting module 2 is disposed at the first opening 12, and the second sound-emitting module 3 is disposed at the second opening 13. The first sound-emitting module 2 has a first speaker 21, and the second sound-emitting module 3 has a second speaker 31. When the microphone 51 under test needs to be tested, the first speaker 21 emits a first detection sound signal. This first detection sound signal, after passing through the microphone 51 under test, is canceled out by a first cancellation sound signal emitted by the second speaker 31. That is, in Figure 2, the first speaker 21 emits a first detection sound signal transmitted to the right, and the second speaker 31 emits a first cancellation sound signal transmitted to the left. The second speaker 31 then emits a second detection sound signal. This second detection sound signal, after passing through the microphone 51 under test, is canceled out by a second cancellation sound signal emitted by the first speaker 21. That is, in Figure 2, the second speaker 31 emits a second detection sound signal transmitted to the left, and the first speaker 21 emits a second cancellation sound signal transmitted to the right. In other words, the microphone 51 under test is approximately in a completely silent environment, and the detection signal reflected from the side walls of the environment will not be reflected to the microphone 51 under test.

[0036] The acoustic parameter measuring device also includes a control circuit 10, with the first speaker 21 and the second speaker 31 electrically connected to the control circuit 10. When the first speaker 21 is used to test the microphone 51 under test, the control circuit 10 sends a first detection signal to the first speaker 21 to make the first speaker 21 emit a first detection sound signal, and sends a first cancellation signal to the second speaker 31 to make the second speaker 31 emit a first cancellation sound signal. When the second speaker 31 is used to test the microphone 51 under test, the control circuit 10 sends a second detection signal to the second speaker 31 to make the second speaker 31 emit a second detection sound signal, and sends a second cancellation signal to the first speaker 21 to make the first speaker 21 emit a second cancellation sound signal. Both the first and second detection sound signals are frequency sweep signals, and the frequency sweep speed can be set according to the microphone 51 under test. The first cancellation sound signal is a sound signal with the same amplitude but opposite phase as the first detection sound signal, and the second cancellation sound signal is a sound signal with the same amplitude but opposite phase as the second detection sound signal. By controlling the time difference between the first canceling sound signal and the first detection sound signal, and between the second canceling sound signal and the second detection sound signal, interference can be caused between the two sets of sound signals, thereby canceling each other out.

[0037] To ensure that the signals sent by the control circuit 10 to the first speaker 21 and the second speaker 31 can be accurately canceled after passing through the microphone under test 51, the control circuit 10 includes a signal delay device 8. The signal delay device 8 can be a first filter or a delay component. Taking the acoustic parameter measuring device using the first speaker 21 to emit a first detection sound signal as an example, the control circuit 10 sends the first detection signal to the first speaker 21, and the first speaker 21 receives the first detection signal and emits the first detection sound signal. The signal delay device 8 is used to delay the time when the first cancellation signal emitted by the control circuit 10 arrives at the second speaker 31. Therefore, the second speaker 31 emits the first cancellation sound signal after the first speaker 21 emits the first detection sound signal, so the propagation distance of the first detection sound signal is greater than the propagation distance of the first cancellation sound signal. Consequently, the first detection sound signal only meets and cancels the first cancellation sound signal after passing through the microphone under test 51.

[0038] However, due to certain losses in the propagation of sound signals, the first detection sound signal or the second detection sound signal experiences physical delay due to the length of the detection tube 1, and the delay value of the signal delay device 8 needs to be adjusted. Therefore, the first cancellation sound signal and the first detection sound signal, the second cancellation sound signal and the second detection sound signal cannot completely cancel each other out, and some sound signals will remain. Specifically, the residual noise signal formed by superimposing the first detection sound signal and the first cancellation sound signal can be called the first reference signal, and the residual noise signal formed by superimposing the second detection sound signal and the second cancellation sound signal can be called the second reference signal. To reduce the residual noise signal, the acoustic parameter measuring device also includes a reference microphone 4 electrically connected to the control circuit 10. The reference microphone 4 collects the first reference signal and the second reference signal. The control circuit 10 adjusts the first cancellation signal according to the first reference signal and adjusts the second cancellation signal according to the second reference signal.

[0039] In this embodiment, the reference microphone 4 includes a first reference microphone 41 and a second reference microphone 42. The first reference microphone 41 is positioned close to the first sound-emitting module 2 and receives the second reference signal, while the second reference microphone 42 is positioned close to the second sound-emitting module 3 and receives the first reference signal. As shown in FIG3, the control circuit 10 further includes a second filter 9. The first reference microphone 41 feeds back the received second reference signal to the second filter 9, and the second reference microphone 42 feeds back the received first reference signal to the second filter 9. The second filter 9 adjusts the signal delay device 8 according to the reference signal (the first reference signal or the second reference signal), so that the delay time is more accurate when the signal delay device 8 sends the second cancellation signal to the first speaker 21 and the first cancellation signal to the second speaker 31. The second filter 9 is an adaptive filter, which can automatically adjust the filter parameters according to the characteristics of the input signal. In this embodiment, the second filter 9 is a Least Mean Square (LMS) filter, which uses the Least Mean Square (LMS) algorithm to continuously adjust the filter weights to minimize the mean square error between the output signal and the desired output signal. In some embodiments, the second filter 9 may also be a Recursive Least Squares (RLS) filter, a Least Mean Square (LMS) filter, an Infinite Impulse Response (IIR) filter, etc. The second filter 9 corrects the delay value of the delay component for the first cancellation signal based on the received first reference signal, and the second filter 9 also corrects the delay value of the delay component for the second cancellation signal based on the received second reference signal, so that the cancellation between the first cancellation sound signal and the first detection sound signal, the second cancellation sound signal and the second detection sound signal is optimized, so that the microphone under test 51 is located in a test environment that is equivalent to a silent environment and occupies a smaller area.

[0040] The detection tube 1 is formed by wrapping it with a side wall 11. The inner wall of the detection tube 1 has a smooth surface to prevent the viscous damping of the inner wall from attenuating the sound waves, thereby reducing test errors. The detection tube 1 is a tubular structure with a circular cross-section. The cross-section of the tubular structure can also be a hollow rectangle, a hollow ellipse, or other shapes. The outer and inner shapes of the cross-section can be the same or different. For example, it can be a structure with a rectangular outer side and a circular inner side. The specific cross-sectional shape is determined according to actual needs. In this embodiment, the inner diameter of the tubular structure is 6 cm and the length is 50 cm. The large aspect ratio provides sufficient area for the superposition and cancellation of the canceling sound (first canceling sound signal and second canceling sound signal) and the detection sound (first detection sound signal and second detection sound signal) during detection. The size of the detection tube 1 can be selected according to actual needs and is not limited here.

[0041] Further, the sidewall 11 also has at least one detection hole 111, which penetrates the sidewall 11 and connects the interior and exterior of the detection tube 1. The detection hole 111 includes a test hole for setting the microphone 51 under test and a reference hole for setting the reference microphone 4. To ensure the structural strength of the sidewall 11 where the detection hole 111 is located, and to provide certain support for the reference microphone 4 and the microphone 51 under test, the thickness of the sidewall 11 at the location of the detection hole 111 is greater than the thickness of the sidewall 11 in other areas. In this embodiment, the distance from the first speaker 21 to the test hole is approximately equal to the distance from the second speaker 31 to the test hole, so that the distance from the microphone 51 under test set in the detection tube 1 through the test hole to the first speaker 21 and the second speaker 31 is approximately equal, which makes the near-field sound wave interference experienced by the reference microphone 4 set in the center of the detection tube 1 less, thereby improving the accuracy of the test. At least two reference holes are respectively positioned close to the first speaker 21 and the second speaker 31, so that of the two reference microphones 4, the first reference microphone 41 is positioned close to the first speaker 21, and the second reference microphone 42 is positioned close to the second speaker 31. In this embodiment, the reference holes and test holes are of the same size, so only a row of detection holes 111 with equal diameters needs to be provided on the side wall 11. The spacing between adjacent detection holes 111 can be equal or unequal.

[0042] The acoustic parameter measuring device includes a detection tube 1 and a first sound-emitting module 2 and a second sound-emitting module 3 disposed on opposite sides of the detection tube 1. The first sound-emitting module 2 is fixedly connected to the detection tube 1 or detachably connected, and the second sound-emitting module 3 is detachably connected to the detection tube 1, thereby allowing the measurement items of the acoustic parameter measuring device to be changed by altering the connection structure at both ends of the detection tube 1. In this embodiment, sealing rings are respectively provided at the connection points of the first sound-emitting module 2 and the detection tube 1, and at the connection points of the second sound-emitting module 3 and the detection tube 1, to ensure that the acoustic parameter measuring device does not leak sound during the measurement process, thus improving the reliability of the test.

[0043] In this embodiment, the first sound-emitting module 2 further includes a first sound-absorbing material 22 disposed on the side of the first speaker 21 away from the second speaker 31; the second sound-emitting module 3 further includes a second sound-absorbing material 32 disposed on the side of the second speaker 31 away from the first speaker 21. The first sound-absorbing material 22 is used to absorb the second detection sound signal emitted by the second speaker 31 but not canceled by the second canceled sound signal, and the second sound-absorbing material 32 is used to absorb the first detection sound signal emitted by the first speaker 21 but not canceled by the first canceled sound signal, further ensuring that no residual noise signal propagates to the microphone 51 under test. The first sound-absorbing material 22 and the second sound-absorbing material 32 can be sound-absorbing panels, sound-insulating cotton, or other materials that can reduce sound reflection and absorb noise. In this embodiment, the first sound-absorbing material 22 wraps around the rear end of the first speaker 21 (the end opposite to the sound-emitting end), and the second sound-absorbing material 32 wraps around the rear end of the second speaker 31 (the end opposite to the sound-emitting end).

[0044] When performing tests using the acoustic parameter measuring device provided in this embodiment of the invention, the microphone under test 51 is first placed in the detection tube 1 through the detection hole 111. When the control circuit 10 sends a first detection signal to the first speaker 21 and a first cancellation signal to the second speaker 31, the signal delay device 8 is configured to delay the output of the first cancellation signal, and the second filter 9 is configured to correct the first cancellation signal. The first detection sound signal is a propagating wave transmitted from the first speaker 21 to the second speaker 31, and the microphone under test 51 receives the first detection sound signal. When the control circuit 10 sends a second detection signal to the second speaker 31 and a second cancellation signal to the first speaker 21, the signal delay device 8 is configured to delay the output of the second cancellation signal, and the second filter 9 is configured to correct the second cancellation signal. The second detection sound signal is a propagating wave transmitted from the second speaker 31 to the first speaker 21, and the microphone under test 51 receives the second detection sound signal. The first and second detection sound signals, transmitted in opposite directions, can simulate sound waves transmitted from the front and rear of the microphone under test 51, respectively. Figure 4 is a frequency response curve obtained by the acoustic parameter measuring device provided in this embodiment of the invention. The two curves in the figure represent the indication effect of the microphone under test 51 on sound waves transmitted from the front and rear, respectively. The greater the difference between the two curves, the better the directivity of the microphone under test 51, indicating that the assembly of the microphone under test 51 does not leak sound. When the microphone under test 51 has a sound leakage problem, the difference between the two lines in the frequency response curve decreases.

[0045] This embodiment of the invention also provides an acoustic material measuring device for measuring the acoustic impedance of acoustic materials. As shown in Figures 5 and 6, the acoustic material testing device includes a detection tube 1 and a first sound-emitting module 2 as described above. The first sound-emitting module 2 is disposed at the first opening 12 of the detection tube 1, and a first detection module 6 is disposed at the second opening 13 of the detection tube 1. The first detection module 6 is used to accommodate the acoustic material 52 to be tested, and the first detection module 6 has a reflection structure 61. The reflection structure 61 is disposed at the second opening 13 and closes the second opening 13. When the acoustic material 52 to be tested is tested, the first loudspeaker 21 generates an initial sound signal. The initial sound signal passes through the acoustic material 52 to be tested, is reflected by the reflection structure 61, and passes through the acoustic material 52 to be tested again to form a detection sound signal. The initial sound signal and the detection sound signal are superimposed to form a generalized standing wave. By measuring the generalized standing wave and performing calculations, the sound absorption coefficient curve of the material can be obtained, and the relevant parameters of the acoustic material 52 to be tested can be obtained.

[0046] In this embodiment, the reflective structure 61 is a boundary with high reflectivity and almost no absorption of sound energy, i.e., a hard boundary. When a sound wave encounters a hard boundary, almost all the sound energy will be reflected back, and almost no sound energy will be absorbed or transmitted into the interior of the boundary. Optionally, the reflective structure 61 is a rigid structure.

[0047] The measuring device also includes a detection microphone 7, which is used to receive initial sound signals and detect sound signals. In this embodiment, the shape and material of the detection tube 1 are as described above. The detection hole 111 is used to house the detection microphone 7, so the shape of the detection hole 111 matches the shape of the detection microphone 7, and the detection microphone 7 passes through the detection hole 111 and is disposed inside the detection tube 1. As shown in FIG6, the sidewall 11 has multiple detection holes 111, and the distances from the multiple detection holes 111 to the first opening 12 are all different. In this embodiment, the acoustic material measuring device includes two detection microphones 7, which are respectively disposed in different detection holes 111. Optionally, the two detection microphones 7 are disposed near the middle between the first sound-emitting module 2 and the first detection module 6.

[0048] When the acoustic material 52 under test is tested, the first loudspeaker 21 generates an initial sound signal. The initial sound signal passes through the acoustic material 52 under test, is reflected by the reflective structure 61, and passes through the acoustic material 52 under test again to form a detection sound signal. The initial sound signal and the detection sound signal are superimposed to form a generalized standing wave. The sound field distribution diagram in the detection tube 1 is shown in Figure 8. The two detection microphones 7 measure the amplitude and phase of the sound signal (including the initial sound signal and the detection sound signal) to obtain the frequency response curve. Then, the response curve is converted into a transfer function. The sound absorption coefficient curve of the acoustic material 52 under test is calculated through the transfer functions of the two microphones, as shown in Figure 7. In some embodiments, the acoustic material 52 under test can be a porous material. The calculated sound absorption coefficient curve of the acoustic material 52 under test is used to fit the parameters of the porous material.

[0049] To further improve the test results, the diameter of the detection tube 1 can be limited to affect the transmission mode and speed of the sound wave within the detection tube 1. Through simulation experiments, it can be seen that when the inner diameter of the detection tube 1 is 10cm, the waveform within the detection tube 1 is a plane wave.

[0050] In this embodiment, the first sound-emitting module 2 further includes a first sound-absorbing material 22 disposed on the side of the first speaker 21 away from the first detection module 6. The first sound-absorbing material 22 is used to absorb the detection sound signal propagating to the first speaker 21, preventing the detection sound signal from continuing to reflect from the first sound-emitting module 2 and thus superimposing with the initial sound signal emitted by the first speaker 21. In this embodiment, the first sound-absorbing material 22 can be a sound-absorbing panel, sound insulation cotton, or other materials that can reduce sound reflection and absorb noise. Optionally, the first sound-absorbing material 22 wraps around the rear end of the first speaker 21 (the end opposite to the sound-emitting end).

[0051] The first sound-emitting module 2 and / or the first detection module 6 are detachably connected to the detection tube 1. In this embodiment, the first sound-emitting module 2 of the acoustic parameter measuring device and the first sound-emitting module 2 of the acoustic material measuring device can have completely identical structures; the detection tube 1 of the acoustic parameter measuring device and the detection tube 1 of the acoustic material measuring device can have completely identical structures, thereby allowing the measurement items of the acoustic parameter measuring device to be changed by altering the structure connected at both ends of the detection tube 1. For example, the first sound-emitting module 2 is connected to the first opening 12 of the detection tube 1, and the second sound-emitting module 3 is connected to the second opening 13 of the detection tube 1. The structure formed at this time is an acoustic parameter measuring device for detecting the microphone 51 under test. The first sound-emitting module 2 is connected to the first opening 12 of the detection tube 1, and the first detection module 6 is connected to the second opening 13. The structure formed at this time is an acoustic material measuring device for detecting the acoustic material 52 under test. In this embodiment, sealing rings are provided at the connection between the first sound-emitting module 2 and the detection tube 1, and at the connection between the first detection module 6 and the detection tube 1, respectively, so as to ensure that the acoustic parameter measuring device does not leak sound during the measurement process and improve the reliability of the test.

[0052] This invention discloses an acoustic parameter measuring device and an acoustic material measuring device. A detection tube and a first sound-emitting module disposed at the first opening of the detection tube can be repeatedly applied to both the acoustic parameter measuring device and the acoustic material measuring device. Different measuring devices can be formed by replacing the module connected to the second opening of the detection tube. Specifically, setting the first detection module at the second opening constitutes an acoustic parameter measuring device to measure the acoustic parameters of the microphone under test, and setting the second sound-emitting module at the second opening constitutes an acoustic material measuring device to measure the acoustic parameters of the acoustic material under test. This invention, by providing a structure with a detection tube and a first sound-emitting module, allows for different acoustic measurements of various products under test after replacing some modules, reducing the space required for testing, the difficulty of testing, and the cost of testing.

[0053] The above description is only a preferred embodiment of this application and is not intended to limit this application. For those skilled in the art, this application can have various modifications and variations. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application. [Simplified Explanation of the Diagram]

[0024] The above and other objects, features and advantages of the present invention will become clearer from the following description of embodiments of the present invention with reference to the drawings, in which: Figure 1 is a three-dimensional structural schematic diagram of the acoustic parameter measuring device provided in an embodiment of the present invention; Figure 2 is a cross-sectional view of the acoustic parameter measuring device provided in an embodiment of the present invention; Figure 3 is a circuit diagram of the acoustic parameter measuring device provided in an embodiment of the present invention; Figure 4 is a frequency response curve obtained by the acoustic parameter measuring device provided in an embodiment of the present invention; Figure 5 is a three-dimensional structural schematic diagram of the acoustic material measuring device provided in an embodiment of the present invention; Figure 6 is a cross-sectional view of the acoustic material measuring device provided in an embodiment of the present invention; Figure 7 is a sound absorption coefficient curve of the acoustic material measuring device provided in an embodiment of the present invention; Figure 8 is a sound field distribution diagram of the acoustic material measuring device provided in an embodiment of the present invention.

Claims

1. An acoustic material measuring device, comprising: A detection tube (1) has a side wall (11) on which at least one detection hole (111) is provided. The detection tube (1) has a first opening (12) and a second opening (13) at opposite ends along the axis, respectively. A first sound-emitting module (2) is disposed at the first opening (12) and has a first loudspeaker (21). A first detection module (6) is detachably connected to the second opening (13) and has a reflective structure (61). The first detection module (6) is used to accommodate an acoustic material (52) to be tested. The first sound-emitting module (2) further includes a first sound-absorbing material (22) disposed on one side of the first speaker (21). The first sound-absorbing material (22) wraps around the rear end of the first speaker (21). The first sound-absorbing material (22) is used to absorb a detection sound signal propagating to the first speaker (21) and prevent the detection sound signal from continuing to reflect from the first sound-emitting module (2) and thus superimposing with an initial sound signal emitted by the first speaker (21).

2. The acoustic material measuring device as described in claim 1, wherein, The reflective structure (61) is located at the second opening (13) and closes the second opening (13).

3. The acoustic material measuring device as described in claim 1, wherein, The initial sound signal generated by the first loudspeaker (21) passes through the acoustic material under test (52), is reflected by the reflective structure (61), and passes through the acoustic material under test (52) again to form the detection sound signal; the acoustic material measuring device also includes a detection microphone (7), which receives the initial sound signal and the detection sound signal.

4. The acoustic material measuring device as described in claim 3, wherein, The shape of the detection hole (111) matches the shape of the detection microphone (7), which passes through the detection hole (111) and is located inside the detection tube (1).

5. The acoustic material measuring apparatus as described in claim 4, wherein, The sidewall (11) has multiple detection holes (111), and the distances from the multiple detection holes (111) to the first opening (12) are all different. The acoustic material measuring device includes two detection microphones (7), and the two detection microphones (7) are respectively set in different detection holes (111).

6. The acoustic material measuring apparatus as described in claim 5, wherein, The detection microphone (7) is positioned between the first sound-emitting module (2) and the first detection module (6).

7. The acoustic material measuring apparatus as described in any one of claims 1 to 6, wherein, The first sound-emitting module (2) also includes the first sound-absorbing material (22) disposed on the side of the first speaker (21) away from the first detection module (6).

8. The acoustic material measuring apparatus as described in claim 3, wherein, The inner diameter of the test tube (1) is 10cm.

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