Microphone array based sound source loudness detector and detection scene adaptation method

Abstract

The application discloses a sound source loudness detector based on a microphone array, which comprises a sound source detector, wherein the sound source detector comprises a sound insulation box body, the sound insulation box body comprises a plurality of side walls which are arranged in a circumferential array, a horn-shaped flared sound collecting port is arranged on each side wall, a plurality of sound receptors based on microphones are arranged in a circumferential array in the sound insulation box body, each sound collecting port corresponds to a sound receptor, and each sound collecting port is connected to the sound receptor through an independent sound guide structure.

Description

Technical Field

[0001] This invention belongs to the field of sound monitoring. Background Technology

[0002] In a fixed sound system arranged in a ring in a large park or plaza, each speaker unit can be considered a point source. Under normal circumstances, the parameters of each speaker unit, as a "point source," are consistent. When located in the center of the ring-shaped fixed sound system, it creates a surround sound effect. However, if one or more of the ring-shaped "point sources" experience non-shutdown malfunctions such as low or high power (loudness), it is difficult for staff to determine the presence of a malfunction by ear, or if so, which one is malfunctioning. Therefore, it is necessary to design a detector that can simultaneously monitor and compare the loudness of each "point source" when entering test mode. Large parks and plazas are not ideally completely open environments and may contain "local obstacles." The influence of these "local obstacles" needs to be offset during testing. Summary of the Invention

[0003] Purpose of the invention: In order to overcome the shortcomings of the existing technology, the present invention provides a sound source loudness detector based on a microphone array and a detection scene adaptation method, which can simultaneously monitor the loudness of each "point sound source" and compare them with each other, thereby offsetting the influence of "local obstacles".

[0004] Technical Solution: To achieve the above objectives, the present invention provides a microphone array-based sound source loudness detector, comprising a sound source detector, the sound source detector comprising a soundproof enclosure, the soundproof enclosure comprising a plurality of side walls arranged in a circumferential array, each side wall being provided with a horn-shaped flared sound collection port; the soundproof enclosure also contains a plurality of microphone-based sound sensors arranged in a circumferential array; each sound collection port corresponds to one sound sensor, and each sound collection port is connected to the sound sensor through an independent sound guiding structure.

[0005] Furthermore, the soundproof enclosure contains a soundproof filling chamber filled with soundproof cotton, and each sound-guiding structure is wrapped in the soundproof cotton inside the soundproof filling chamber.

[0006] Furthermore, the sound sensor includes a vertical sound tube with a cap at the top and a diaphragm coaxially arranged on the sound tube. The upper side of the diaphragm is a signal conversion chamber, and the lower side of the diaphragm is a sound chamber.

[0007] An electromagnetic induction coil is coaxially connected to the upper side of the diaphragm. The electromagnetic induction coil oscillates synchronously with the diaphragm. A permanent magnet is fixedly installed inside the signal conversion chamber, with one end of the permanent magnet extending into the electromagnetic induction coil. The oscillation of the electromagnetic induction coil in the magnetic field near the permanent magnet causes the electromagnetic induction coil to generate an induced current. It also includes a current detection unit that can detect the intensity of the induced current of the electromagnetic induction coil.

[0008] Furthermore, the sound guiding structure includes a sound guiding bend, inside which is a sound guiding channel. The narrow end of the sound collecting port is connected to the lower end of the sound tube through the sound guiding channel.

[0009] Furthermore, the lower inner wall of the sound tube is provided with an annular groove and also includes an annular elastic sheet. The upper and lower contour edges of the annular elastic sheet are respectively sealed and bonded to the upper and lower inner walls of the annular groove, so that a liquid oil-filled annular cavity is formed between the annular elastic sheet and the inner wall of the annular groove. The liquid oil-filled annular cavity is filled with an oily liquid. The liquid oil-filled annular cavity filled with oily liquid and the annular elastic sheet together constitute a variable sound guiding throat. A throat channel that runs vertically through the enclosed area of ​​the variable sound guiding throat is formed. The upper and lower ends of the throat channel are connected to the sound chamber and the sound guiding channel, respectively.

[0010] Furthermore, each sound tube has an oil filling cylinder on one side, with an oil filling chamber filled with an oily substance inside. A plunger is movably installed inside the oil filling cylinder, and the end of the oil filling chamber away from the plunger is connected to the liquid oil filling ring cavity through an oil guide channel. It also includes a linear motor, with the end of the linear push rod of the linear motor connected to the plunger. When the linear push rod pushes the plunger, the oily liquid in the oil filling chamber is forced into the liquid oil filling ring cavity through the oil guide channel, causing the annular elastic sheet to expand inward, thereby narrowing the throat passage.

[0011] Furthermore, the sound source detector has eight flared, trumpet-shaped sound collection ports, which are arranged in a circular array around the soundproof enclosure. Eight point sound sources are arranged in a circular array with equal radii around the sound source detector, and the sound source detector simultaneously monitors the eight point sound sources around its own periphery.

[0012] Furthermore, a detection scene adaptation method for a microphone array-based sound source loudness detector:

[0013] The eight sound sources are designated as the first, second, third, fourth, fifth, sixth, seventh, and eighth sound sources. The scene surrounding the sound source detectors is not an ideal open area and contains "local obstacles." The standard first, second, third, fourth, fifth, sixth, seventh, and eighth sound sources simultaneously emit sounds with consistent loudness.

[0014] Due to the presence of "local obstructions," the current intensities detected by the eight electromagnetic induction coils are inconsistent. The variable sound-conducting throat below the electromagnetic induction coil with a high detected current intensity is selected. By controlling the movement of the plunger, the oily liquid in the oil filling chamber is forced into the selected liquid oil filling ring cavity through the oil guide channel. This causes the selected annular elastic sheet to expand inward, narrowing the throat channel. The narrower throat channel reduces the sound intensity ultimately transmitted to the sound chamber, thereby reducing the sensitivity of the diaphragm. As a result, the current intensity of the electromagnetic induction coil with a high detected current intensity is reduced to be consistent with the current intensity of the other electromagnetic induction coils, thus counteracting the effect of the "local obstructions."

[0015] After the influence of "local obstacles" is canceled out, when monitoring the first, second, third, fourth, fifth, sixth, seventh, and eighth sound sources, if the current intensity detected on each of the eight electromagnetic induction coils is consistent, it indicates that the loudness of the sound sources emitted by the first, second, third, fourth, fifth, sixth, seventh, and eighth sound sources is consistent, indicating that they are qualified. If the current intensity detected on each of the eight electromagnetic induction coils is inconsistent, it indicates that there is a problem with the sound being too high or too low among the first, second, third, fourth, fifth, sixth, seventh, and eighth sound sources.

[0016] Beneficial effects: This invention can simultaneously monitor and compare the loudness of each "point sound source". When the linear push rod pushes the plunger, the oily liquid in the oil filling chamber is forced into the liquid oil filling ring cavity through the oil guide channel, causing the annular elastic latex sheet to expand inward, thereby narrowing the throat channel. The narrower throat channel reduces the sound intensity transmitted to the sound chamber, thus reducing the sensitivity of the diaphragm. By controlling the detection sensitivity in a single direction through the above principle, the amplifying effect of sound reflection from "local obstacles" can be offset. Attached Figure Description

[0017] Appendix Figure 1 This is a schematic diagram of the overall structure of the sound source detector;

[0018] Appendix Figure 2 For the appendix Figure 1 The first sectional view;

[0019] Appendix Figure 3 For the appendix Figure 1 The second sectional view;

[0020] Appendix Figure 4 For the appendix Figure 3 An enlarged view of mark 10;

[0021] Appendix Figure 5 For the appendix Figure 4 Side view;

[0022] Appendix Figure 6 For the appendix Figure 5 An enlarged view of mark 11;

[0023] Appendix Figure 7 This is a schematic diagram showing the positional relationship between eight point sound sources and sound source detectors. Detailed Implementation

[0024] The invention will now be further described with reference to the accompanying drawings.

[0025] As attached Figures 1 to 7 The microphone array-based sound source loudness detector shown includes a sound source detector 4, which includes a soundproof enclosure 6. The soundproof enclosure 6 includes several side walls 7 arranged in a circular array, and each side wall is provided with a horn-shaped flared sound collection port 8. Several microphone-based sound sensors are also arranged in a circular array inside the soundproof enclosure 6. Each sound collection port 8 corresponds to a sound sensor, and each sound collection port 8 is connected to the sound sensor through an independent sound guiding structure.

[0026] like Figure 2 and 3 The soundproof enclosure 6 contains a soundproof filling chamber 13 filled with soundproof cotton, and each sound guiding structure is wrapped in the soundproof cotton inside the soundproof filling chamber 13.

[0027] The sound sensor includes a vertical sound tube 14, a cap 33 at the top of the sound tube 14, a diaphragm 21 coaxially disposed on the sound tube 14, a signal conversion chamber 17.2 on the upper side of the diaphragm 21, and a sound chamber 17.1 on the lower side of the diaphragm 21.

[0028] like Figure 3 , 4 5, 6; An electromagnetic induction coil 20 is coaxially connected to the upper side of the diaphragm 21. The electromagnetic induction coil 20 oscillates synchronously with the diaphragm 21. A permanent magnet 19 is fixedly installed inside the signal conversion chamber 17.2. One end of the permanent magnet 19 extends into the electromagnetic induction coil 20. The oscillation of the electromagnetic induction coil 20 in the magnetic field near the permanent magnet 19 causes the electromagnetic induction coil 20 to generate an induced current. It also includes a current detection unit that can detect the intensity of the induced current of the electromagnetic induction coil 20.

[0029] The sound guiding structure includes a sound guiding bend 12, inside which is a sound guiding channel 27. The narrow end of the sound collecting port 8 is connected to the lower end of the sound tube 14 through the sound guiding channel 27.

[0030] The lower inner wall of the sound cylinder 14 is provided with an annular groove 16, and also includes an annular elastic latex sheet 15. The upper and lower contour edges 015 of the annular elastic latex sheet 15 are respectively sealed and bonded to the upper and lower inner side walls 16.1 of the annular groove 16, so that an oil-filled annular cavity 18 is formed between the annular elastic latex sheet 15 and the inner wall of the annular groove 16. The oil-filled annular cavity 18 is filled with an oily liquid, such as transformer oil. The oil-filled annular cavity 18 filled with oily liquid and the annular elastic latex sheet 15 together constitute a variable sound-conducting throat 34. A vertically penetrating throat channel 26 is formed within the enclosed area of ​​the variable sound-conducting throat 34. The upper and lower ends of the throat channel 26 are respectively connected to the sound chamber 17.1 and the sound-conducting channel 27. Each side is provided with an oil injection cylinder 22, and the oil injection cylinder 22 contains an oil injection chamber 24 filled with an oily substance. A plunger 23 is movably installed in the oil injection cylinder 22. The end of the oil injection chamber 24 away from the plunger 23 is connected to the liquid oil filling annular cavity 18 through an oil guide channel 25. It also includes a linear motor 50. The end of the linear push rod 51 of the linear motor 50 is connected to the plunger 23. When the linear push rod 51 pushes the plunger 23, the oily liquid in the oil injection chamber 24 is forced into the liquid oil filling annular cavity 18 through the oil guide channel 25, causing the annular elastic latex sheet 15 to expand inward, thereby narrowing the throat channel 26. The narrower throat channel 26 reduces the sound intensity that is finally transmitted to the sound chamber 17.1, thereby reducing the sensitivity of the diaphragm 21.

[0031] A detection scene adaptation method for microphone array-based sound source loudness detectors

[0032] like Figure 7 As shown, in scenarios such as testing a sound system distributed in a circular pattern in a square, the distribution and number of sound collection ports 8 depend on the specific arrangement of the sound system. To better explain this device, the sound source loudness detector 4 of this scheme has eight flared, trumpet-shaped sound collection ports 8, which are arranged in a circular array around the soundproof enclosure 6. The sound source detector 4 simultaneously monitors the sound nodes of the eight sound source squares around its own perimeter. If the eight sound sources enter the test mode, the eight sound sources simultaneously emit test sounds of the same power. If the sound source detector 4 determines that the loudness emitted by the eight sound sources is consistent, then it is qualified.

[0033] The scenario where the sound source detector 4 is positioned in an ideal open area:

[0034] In the initial state, the inner diameter of the narrowest part of the eight throat channels 26 on the sound source detector 4 is the same; the eight directions corresponding to the eight sound collection ports 8 of the sound source detector 4 are all in an ideal situation of absolute openness. Eight point sound sources are distributed in a circular array with equal radii around the outer periphery of the sound source detector 4. The eight point sound sources correspond to the eight sound collection ports 8 respectively. The eight point sound sources are the first point sound source 1.1, the second point sound source 1.2, the third point sound source 1.3, the fourth point sound source 1.4, the fifth point sound source 1.5, the sixth point sound source 1.6, the seventh point sound source 1.7 and the eighth point sound source 1.8.

[0035] During monitoring, if sound sources 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, and 1.8 simultaneously emit test sounds with identical loudness, and since the sound source detector 4 is in an open environment, the eight sound collection ports 8 will not receive reflected sound waves. Therefore, the sound wave intensity received by the eight sound collection ports 8 is consistent. Because the inner diameter of the narrowest point of the eight throat channels 26 is consistent in the initial state, the sound waves received by the eight sound collection ports 8 pass through their respective sound guide channels. The sound intensity transmitted from 27 and the throat passage 26 to the eight sound chambers 17.1 is consistent, thus making the oscillation intensity of the eight electromagnetic induction coils 20 consistent. The current intensity detected on each of the eight electromagnetic induction coils 20 is also consistent. At this time, based on the fact that the current intensity detected on each of the eight electromagnetic induction coils 20 is consistent, it is determined that the loudness of the sound emitted by the first sound source 1.1, the second sound source 1.2, the third sound source 1.3, the fourth sound source 1.4, the fifth sound source 1.5, the sixth sound source 1.6, the seventh sound source 1.7, and the eighth sound source 1.8 is consistent, indicating that it is normal and qualified.

[0036] Similarly, if the loudness of the sounds emitted by the first sound source 1.1, the second sound source 1.2, the third sound source 1.3, the fourth sound source 1.4, the fifth sound source 1.5, the sixth sound source 1.6, the seventh sound source 1.7, and the eighth sound source 1.8 are inconsistent, the intensity of the sound waves received by the eight corresponding sound collection ports 8 will also be inconsistent, ultimately causing the oscillation intensity of the eight electromagnetic induction coils 20 to be inconsistent as well. Therefore, the loudness of the first sound source 1.1, the second sound source 1.2, the third sound source 1.3, the fourth sound source 1.4, the fifth sound source 1.5, the sixth sound source 1.6, the seventh sound source 1.7, and the eighth sound source 1.8 can be determined based on the magnitude of the current intensity detected on the eight electromagnetic induction coils 20.

[0037] As can be seen from the above process, in a scenario where the sound source detector 4 is positioned in an ideal open area, and the inner diameter of the narrowest point of the eight throat channels 26 in the sound source detector 4 is the same, the sound source detector 4 can accurately compare the intensity of the sound emitted by the first sound source 1.1, the second sound source 1.2, the third sound source 1.3, the fourth sound source 1.4, the fifth sound source 1.5, the sixth sound source 1.6, the seventh sound source 1.7 and the eighth sound source 1.8 by detecting the current intensity on the eight electromagnetic induction coils 20 respectively.

[0038] Therefore, the initial setup of the sound source detector 4 is adapted to a scenario of an ideal open area;

[0039] The location where sound source detector 4 is placed is not in an ideal open area:

[0040] For example, there is a "local obstacle" not far from the side of the eighth sound source 1.8 away from the sound source detector 4; if the inner diameter of the narrowest part of the eight throat channels 26 in the sound source detector 4 is still the same, when the first sound source 1.1, the second sound source 1.2, the third sound source 1.3, the fourth sound source 1.4, the fifth sound source 1.5, the sixth sound source 1.6, the seventh sound source 1.7 and the eighth sound source 1.8 simultaneously emit sounds of the same loudness, because the "local obstacle" will reflect part of the sound, the sound collection port 8 corresponding to the eighth sound source 1.8 and the adjacent sound collection port 8 will receive not only the sound emitted by the "sound source" but also part of the sound reflected by the "local obstacle"; therefore, the sound intensity received by the sound collection port 8 corresponding to the eighth sound source 1.8 and the adjacent sound collection port 8 is greater than the sound received by the other sound collection ports 8; thus causing the current intensity detected on the eight electromagnetic induction coils 20 to be inconsistent;

[0041] Although the first sound source 1.1, the second sound source 1.2, the third sound source 1.3, the fourth sound source 1.4, the fifth sound source 1.5, the sixth sound source 1.6, the seventh sound source 1.7, and the eighth sound source 1.8 all emitted sound at the same time with the same actual loudness, the current intensity detected on the eight electromagnetic induction coils 20 was inconsistent, and the detection results did not match the actual situation.

[0042] Therefore, the initial settings of sound source detector 4 are not suitable for scenarios in non-ideal open areas. It is necessary to adapt it to these scenarios, and the specific process is as follows:

[0043] Before setting up the plaza's sound system, standard point source 1.1, point source 1.2, point source 1.3, point source 1.4, point source 1.5, point source 1.6, point source 1.7, and point source 1.8 were used to simultaneously emit sounds with the same actual loudness.

[0044] Due to the presence of "local obstructions," the current intensities detected by the eight electromagnetic induction coils 20 are inconsistent. Therefore, it is necessary to eliminate and cancel out the influence of "local obstructions." At this time, the variable sound-conducting throat 34 below the electromagnetic induction coil 20 with a high detected current intensity is selected. By controlling the movement of the plunger 23, the oily liquid in the oil filling chamber 24 is forced into the selected liquid oil filling ring cavity 18 through the oil guiding channel 25. This causes the selected annular elastic latex sheet 15 to expand inward, and the throat channel 26 to narrow. The narrower throat channel 26 reduces the sound intensity ultimately transmitted to the sound chamber 17.1, thereby reducing the sensitivity of the diaphragm 21. As a result, the current intensity of the electromagnetic induction coil 20 with a high detected current intensity is reduced to be consistent with the current intensity of the other electromagnetic induction coils 20, thus canceling out the influence of "local obstructions."

[0045] After eliminating the influence of "local obstacles" through the above steps, when monitoring the first sound source 1.1, the second sound source 1.2, the third sound source 1.3, the fourth sound source 1.4, the fifth sound source 1.5, the sixth sound source 1.6, the seventh sound source 1.7, and the eighth sound source 1.8, if the current intensity detected on each of the eight electromagnetic induction coils 20 is consistent, it indicates that the loudness of the sound sources emitted by the first sound source 1.1, the second sound source 1.2, the third sound source 1.3, the fourth sound source 1.4, the fifth sound source 1.5, the sixth sound source 1.6, the seventh sound source 1.7, and the eighth sound source 1.8 is consistent, indicating that it is qualified; if the current intensity detected on each of the eight electromagnetic induction coils 20 is consistent, it indicates that it is qualified. If the current intensities detected on the eight electromagnetic induction coils 20 are inconsistent, it indicates that the sound from the first sound source 1.1, the second sound source 1.2, the third sound source 1.3, the fourth sound source 1.4, the fifth sound source 1.5, the sixth sound source 1.6, the seventh sound source 1.7, and the eighth sound source 1.8 is either too high or too low. Therefore, the loudness of the first sound source 1.1, the second sound source 1.2, the third sound source 1.3, the fourth sound source 1.4, the fifth sound source 1.5, the sixth sound source 1.6, the seventh sound source 1.7, and the eighth sound source 1.8 can be determined by the magnitude of the current intensity detected on the eight electromagnetic induction coils 20.

[0046] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A sound source loudness detector based on a microphone array, characterized in that: The sound source detector (4) comprises a sound insulation box (6) comprising a plurality of side walls (7) distributed in a circumferential array, each of which is provided with a horn-shaped flared sound collecting port (8); a plurality of sound receptors based on microphones are also distributed in a circumferential array in the sound insulation box (6); each sound collecting port (8) corresponds to a sound receptor, and each sound collecting port (8) is connected to the sound receptor through an independent sound guide structure; The sound receptor comprises a vertical sound cylinder (14), the coaxial center of the sound cylinder (14) is provided with a diaphragm (21), the upper side of the diaphragm (21) is a signal conversion chamber (17.2), and the lower side of the diaphragm (21) is a sound chamber (17.1); The upper coaxial center of the diaphragm (21) is connected with an electromagnetic induction coil (20), the electromagnetic induction coil (20) oscillates synchronously with the diaphragm (21), a permanent magnet (19) is fixedly installed in the signal conversion chamber (17.2), one end of the permanent magnet (19) extends into the electromagnetic induction coil (20), and the oscillation of the electromagnetic induction coil (20) in the magnetic field near the permanent magnet (19) causes the electromagnetic induction coil (20) to form an induced current; The sound guide structure comprises a sound guide elbow (12), the sound guide elbow (12) is a sound guide channel (27), and the sound guide channel (27) is in communication with the fine end of the sound collecting port (8) and the lower end of the sound cylinder (14); The lower end inner wall of the sound cylinder (14) is provided with an annular groove (16), and an annular elastic sheet (15) is further arranged, the upper and lower profile edges (015) of the annular elastic sheet (15) are respectively sealed and bonded with the upper and lower inner side walls (16.1) of the annular groove (16), so that a liquid oil filling annular cavity (18) is formed between the annular elastic sheet (15) and the inner wall of the annular groove (16), and the liquid oil filling annular cavity (18) is filled with an oily liquid; the liquid oil filling annular cavity (18) filled with the oily liquid and the annular elastic sheet (15) jointly form a variable sound guide throat pipe (34), a throat pipe channel (26) penetrating from top to bottom is formed in the surrounding range of the variable sound guide throat pipe (34), and the upper and lower ends of the throat pipe channel (26) are respectively in communication with the sound chamber (17.1) and the sound guide channel (27); Each of the sound cylinders (14) is provided with an oil injection cylinder (22) on one side, the oil injection cylinder (22) is filled with oily substance, a plunger (23) is movably arranged in the oil injection cylinder (22), and the oil injection warehouse (24) far away from the plunger (23) is communicated with the liquid oil filling ring cavity (18) through an oil guide channel (25); a linear motor (50) is further arranged, and the linear push rod (51) of the linear motor (50) is connected with the plunger (23); when the linear push rod (51) pushes the plunger (23), the oily liquid in the oil injection warehouse (24) is pressed into the liquid oil filling ring cavity (18) through the oil guide channel (25), so that the annular elastic sheet (15) is inflated inward, thereby narrowing the throat channel (26), and the narrower throat channel makes the sound intensity transmitted to the sound chamber finally lower, and the sensitivity of the diaphragm is further reduced.

2. The microphone array based acoustic source loudness detector of claim 1, wherein: The sound insulation box body (6) is filled with sound insulation cotton in the sound insulation filling warehouse (13), and each of the sound guide structures is wrapped in the sound insulation cotton in the sound insulation filling warehouse (13).

3. The microphone array based acoustic source loudness detector of claim 2, wherein: The sound cylinder (14) is provided with a cover (33) at the top end.

4. The microphone array based acoustic source loudness detector of claim 3, wherein: A current detection unit capable of detecting the induction current intensity of the electromagnetic induction coil (20) is further included.

5. The microphone array based acoustic source loudness detector of claim 4, wherein: The sound source detector (4) has eight trumpet-shaped sound collecting openings (8) which are arranged in a circular array around the sound insulation box body (6); eight point sound sources are arranged in a circular array at the same radius around the sound source detector (4), and the sound source detector (4) simultaneously monitors the eight point sound sources around it.

6. The sound source loudness detector based on the microphone array according to claim 5, wherein: The eight point sound sources are respectively a first point sound source (1.1), a second point sound source (1.2), a third point sound source (1.3), a fourth point sound source (1.4), a fifth point sound source (1.5), a sixth point sound source (1.6), a seventh point sound source (1.7), and an eighth point sound source (1.8); the scene around the sound source detector (4) is not an ideal open area, and there is a "local obstacle"; the standard first point sound source (1.1), the second point sound source (1.2), the third point sound source (1.3), the fourth point sound source (1.4), the fifth point sound source (1.5), the sixth point sound source (1.6), the seventh point sound source (1.7), and the eighth point sound source (1.8) simultaneously emit sound with the same actual loudness. Due to the existence of "local obstacles", the current intensity detected on the eight electromagnetic induction coils (20) is inconsistent, and the variable sound guide throat (34) under the electromagnetic induction coil (20) with high current intensity is selected. By controlling the movement of the plunger (23), the oily liquid in the oil tank (24) is pressed into the selected liquid oil filling ring cavity (18) through the oil guide channel (25), so that the selected annular elastic sheet (15) expands inward, the throat channel (26) narrows, and the narrower throat channel (26) makes the sound intensity transmitted to the sound chamber (17.1) lower, thereby reducing the sensitivity of the diaphragm (21), so that the current intensity of the electromagnetic induction coil (20) with high current intensity is reduced to be consistent with the current intensity of the other electromagnetic induction coils (20), and the influence of "local obstacles" is offset. After the influence of "local obstacles" is offset, when monitoring the first sound source (1.1), the second sound source (1.2), the third sound source (1.3), the fourth sound source (1.4), the fifth sound source (1.5), the sixth sound source (1.6), the seventh sound source (1.7) and the eighth sound source (1.8), if the current intensity detected on the eight electromagnetic induction coils (20) is consistent, it indicates that the sound source loudness of the first sound source (1.1), the second sound source (1.2), the third sound source (1.3), the fourth sound source (1.4), the fifth sound source (1.5), the sixth sound source (1.6), the seventh sound source (1.7) and the eighth sound source (1.8) is consistent, which indicates that it is qualified; If the current intensity detected on the eight electromagnetic induction coils (20) is inconsistent, it indicates that there is a high or low sound in the first sound source (1.1), the second sound source (1.2), the third sound source (1.3), the fourth sound source (1.4), the fifth sound source (1.5), the sixth sound source (1.6), the seventh sound source (1.7) and the eighth sound source (1.8).

Images