Acoustic testing device for air conditioner air duct

Abstract

The invention provides an acoustic testing device for an air conditioner air duct, and belongs to the technical field of testing. The acoustic testing device comprises a first impedance tube, a second impedance tube, a microphone, a data collector and a signal processor; the first impedance tube and the second impedance tube are respectively arranged at two ends of a tested air conditioner duct, a first end of the first impedance tube is provided with a sound source, a first output end of the data collector is used for outputting a voltage signal to drive the sound source to output a sound wave signal, and a microphone is arranged on the wall or inside of each of the first impedance tube and the second impedance tube; the output end of the microphone is connected to the signal processor through the data collector, and the signal processor is used for calculating the transmission loss of the tested air conditioner air duct based on the output data of the microphone in the first state and the output data of the microphone in the second state to obtain the acoustic test result of the tested air conditioner air duct. According to the acoustic testing device for the air conditioner air duct, the testing precision can be improved while the testing cost is reduced.

Description

Technical Field

[0001] This application relates to the field of testing technologies, and particularly to an air-conditioning duct acoustic testing device. Background Art

[0002] Under the trend of automotive intelligentization and electrification, the in-vehicle vibration and noise performance (NVH) has become a core indicator that consumers focus on. As a key channel for air flow and noise transmission, the transmission loss characteristics of the air-conditioning duct directly determine the in-vehicle acoustic comfort. Regarding the transmission loss of the air-conditioning duct, the existing testing methods currently include the two-source method and the pulse method. Among them, the two-source method requires two sound sources and the performance of the two sound sources to be consistent. If the sound sources are unstable, it will lead to measurement errors; the pulse method requires no reflection in the pipeline, a very long pipeline, which is difficult to achieve, and the pulse method relies on short-time strong signal acquisition and is greatly affected by ambient noise. Summary of the Invention

[0003] Embodiments of this application provide an air-conditioning duct acoustic testing device to improve the testing accuracy while reducing the testing cost.

[0004] Embodiments of this application provide an air-conditioning duct acoustic testing device, including a first impedance tube, a second impedance tube, a microphone, a data collector, and a signal processor; A sound source is arranged at the first end of the first impedance tube. The first output end of the data collector is used to output a voltage signal to drive the sound source to output a sound wave signal. The second end of the first impedance tube is used to be connected to the first end of the air-conditioning duct to be tested. The first end of the second impedance tube is used to be connected to the second end of the air-conditioning duct to be tested. The microphone is arranged on the tube wall or inside of each of the first impedance tube and the second impedance tube; The output end of the microphone is connected to the signal input end of the data collector. The second output end of the data collector is connected to the signal input end of the signal processor. The signal processor is used for: Calculating the transmission loss of the air-conditioning duct to be tested based on the output data of the microphone in the first state and the output data of the microphone in the second state, to obtain the acoustic testing result of the air-conditioning duct to be tested; Wherein, in the first state, an acoustic absorption material is arranged at the second end of the second impedance tube. In the second state, no acoustic absorption material is arranged at the second end of the second impedance tube.

[0005] In an exemplary embodiment of this application, the microphone includes a first microphone, a second microphone, a third microphone, and a fourth microphone; the first microphone and the second microphone are arranged on the tube wall or inside of the first impedance tube, and the third microphone and the fourth microphone are arranged on the tube wall or inside of the second impedance tube; The signal processor is specifically configured to: Calculate the transmission loss of the air duct of the air conditioner under test through a first formula; the first formula is: ; Wherein, ; ; ; ; Wherein, is the transmission loss, is the transmission coefficient, , , , are respectively the sound pressure data measured by four microphones in the or 2, represents the first state, represents the second state, , are respectively the distances from the first microphone and the second microphone to the end face of the first end of the air duct of the air conditioner under test, , are respectively the distances from the third microphone and the fourth microphone to the end face of the second end of the air duct of the air conditioner under test, is the incident wave in the is the transmitted wave in the is the reflected wave of the second impedance tube in the represents the wave number of the acoustic wave signal, is the imaginary part.

[0006] In an exemplary embodiment of the present application, the signal processor is specifically further configured to: Determine an adjustment parameter based on the reflection coefficient of the sound-absorbing material, and the adjustment parameter has a negative correlation with the reflection coefficient; Correct the transmission loss based on the adjustment parameter.

[0007] In an exemplary embodiment of the present application, the signal processor is specifically further configured to: Determine a proportional parameter based on the reflection coefficient of the sound-absorbing material; Determine the adjustment parameter based on the reflection coefficient of the sound-absorbing material and the proportional parameter.

[0008] In an exemplary embodiment of the present application, a test hole is provided on the tube wall of the first impedance tube, and the microphone is arranged in the test hole.

[0009] In an exemplary embodiment of the present application, the number of microphones provided on the tube wall of the first impedance tube is two, and the number of test holes provided on the tube wall of the first impedance tube is at least two.

[0010] In an exemplary embodiment of the present application, the air duct acoustic testing device further includes: For the air duct under test with different apertures, the distance between the test holes is different.

[0011] In an exemplary embodiment of the present application, both between the first impedance tube and the air duct under test and between the second impedance tube and the air duct under test are connected through a test tooling.

[0012] In an exemplary embodiment of the present application, a power amplifier is provided between the first output end of the data collector and the sound source.

[0013] In an exemplary embodiment of the present application, the air duct acoustic testing device further includes: A test chamber; wherein, the first impedance tube, the second impedance tube, the microphone, the data collector and the signal processor are all provided in the test chamber.

[0014] The beneficial effects of the air duct acoustic testing device provided by the embodiments of the present application are as follows: In the embodiments of the present application, by providing an acoustic absorption material (first state) and not providing an acoustic absorption material (second state) at the end (second end) of the second impedance tube, two different acoustic load conditions are formed, and the transmission loss is calculated according to the sound pressure data collected by the microphone in the two states, improving the accuracy of the acoustic testing of the air duct under test.

[0015] Compared with the existing double sound source method, the method of the embodiments of the present application only requires one sound source, reducing the equipment cost and the difficulty of synchronous control, and at the same time avoiding the error caused by the inconsistency of the sound sources; compared with the existing impulse method, the method of the embodiments of the present application does not require a very long pipeline, has a compact structure, is suitable for laboratory and on-site testing, and moreover, the method of this embodiment can reduce the influence of environmental noise through differential processing under two load conditions, improving the reliability of the test results. Description of the Drawings

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required for use in the embodiments or the description of the prior art. Obviously, the following drawings are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained according to these drawings.

[0017] Figure 1 It is a schematic structural diagram of an air-conditioning duct acoustic testing device provided by an embodiment of the present application; Figure 2 It is a flowchart of an air-conditioning duct acoustic testing method provided by an embodiment of the present application; Figure 3 It is a schematic diagram of a transmission loss curve provided by an embodiment of the present application; In the figure: 1 - power amplifier, 2 - loudspeaker, 3 - first impedance tube, 4 - first microphone, 5 - test hole, 6 - second microphone, 7 - test tooling, 8 - air-conditioning duct to be tested, 9 - second impedance tube, 10 - third microphone, 11 - fourth microphone, 12 - data collector, 13 - signal processing software, 14 - test chamber. Specific embodiments

[0018] In order to enable those skilled in the art to better understand this solution, the following will clearly describe the technical solutions in the embodiments of this solution with reference to the accompanying drawings in the embodiments of this solution. Obviously, the described embodiments are some, but not all, of the embodiments of this solution. Based on the embodiments in this solution, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the scope of protection of this solution.

[0019] The term "including" in the specification, claims and above-mentioned accompanying drawings of this solution, as well as any other variations, means "including but not limited to", and is intended to cover non-exclusive inclusion, not limited only to the examples listed in the text. In addition, terms such as "first" and "second" are used to distinguish different objects, rather than to describe a specific order.

[0020] The following will give a detailed description of the implementation of the present application with reference to specific accompanying drawings: Figure 1 It is a schematic structural diagram of an air-conditioning duct acoustic testing device provided by an embodiment of the present application. Referring to Figure 1 , this air-conditioning duct acoustic testing device includes a first impedance tube 3, a second impedance tube 9, a microphone, a data collector 12 and a signal processor; A sound source is provided at the first end of the first impedance tube 3. The first output end of the data collector 12 is used to output a voltage signal to drive the sound source to output a sound wave signal. The second end of the first impedance tube 3 is used to connect to the first end of the air-conditioning duct 8 to be tested. The first end of the second impedance tube 9 is used to connect to the second end of the air-conditioning duct 8 to be tested. A microphone is provided on the wall or inside of each of the first impedance tube 3 and the second impedance tube 9; The output end of the microphone is connected to the signal input end of the data collector 12. The second output end of the data collector 12 is connected to the signal input end of the signal processor. The signal processor is used for: Based on the output data of the microphone in the first state and the output data of the microphone in the second state, calculate the transmission loss of the measured air-conditioning duct 8 to obtain the acoustic test result of the measured air-conditioning duct 8; Among them, in the first state, an acoustic absorption material is provided at the second end of the second impedance tube 9, and in the second state, no acoustic absorption material is provided at the second end of the second impedance tube 9.

[0021] In this embodiment, the first impedance tube 3 and the second impedance tube 9 are respectively arranged at the front end and the rear end of the measured air-conditioning duct 8, and a sound source (such as the loudspeaker 2) is arranged at the front end (the first end) of the first impedance tube 3. By setting the parameters of the data collector 12, a voltage signal of a specified level can be output at the first output end of the data collector 12, and this voltage signal can drive the sound source inside the first impedance tube 3 to output a sound wave signal (plane wave sound field).

[0022] At the same time, microphones (ICP type microphones) are arranged on the tube wall or inside of the first impedance tube 3 and on the tube wall or inside of the second impedance tube 9, respectively, for detecting the sound pressure data at the corresponding positions and sending them to the signal input end of the data collector 12. Arranging an acoustic absorption material at the end (the second end) of the second impedance tube 9 can form a non-reflecting end (the first state) at the end of the second impedance tube 9, and not arranging an acoustic absorption material at the end (the second end) of the second impedance tube 9 can form a rigid end (the second state) at the end of the second impedance tube 9. After the sound pressure data collected by the microphones in the two states are sent to the signal input end of the data collector 12, they are sent to the signal processor through the second output end of the data collector 12.

[0023] The signal processor can be implemented by Figure 1 the signal processing software 13 therein. The signal processor performs differential processing on the sound pressure data collected by the microphones in the two states, and can obtain the transmission loss of the measured air-conditioning duct 8, that is, the acoustic test result of the measured air-conditioning duct 8.

[0024] It can be concluded from the above that in this embodiment, by arranging an acoustic absorption material (the first state) and not arranging an acoustic absorption material (the second state) at the end (the second end) of the second impedance tube 9, two different acoustic load conditions are formed, and the transmission loss is calculated according to the sound pressure data collected by the microphones in the two states, improving the accuracy of the acoustic test of the measured air-conditioning duct 8.

[0025] Compared with the existing double sound source method, the method of this embodiment only requires one sound source, reducing the equipment cost and the difficulty of synchronous control, and at the same time avoiding the error caused by the inconsistency of the sound sources; compared with the existing pulse method, the method of this embodiment has a compact structure, is suitable for laboratory and on-site tests, and improves the reliability of the test results.

[0026] In an exemplary embodiment of the present application, the microphone includes a first microphone 4, a second microphone 6, a third microphone 10, and a fourth microphone 11; the first microphone 4 and the second microphone 6 are disposed on the wall or inside of the first impedance tube 3, and the third microphone 10 and the fourth microphone 11 are disposed on the wall or inside of the second impedance tube 9; The signal processor is specifically configured to: Calculate the transmission loss of the measured air-conditioning duct 8 through a first formula; the first formula is: ; Wherein, ; ; ; ; Wherein, is the transmission loss, is the transmission coefficient, , , , are respectively the sound pressure data measured by the four microphones in the or 2, represents the first state, represents the second state, , are respectively the distances from the first microphone 4 and the second microphone 6 to the end face of the first end of the measured air-conditioning duct 8, , are respectively the distances from the third microphone 10 and the fourth microphone 11 to the end face of the second end of the measured air-conditioning duct 8, is the incident wave in the state, is the transmitted wave in the state, is the reflected wave of the second impedance tube 9 in the

[0027] In this embodiment, the number of microphones is four, which are respectively disposed at corresponding positions of the first impedance tube 3 and the second impedance tube 9. The sound wave signal emitted by the sound source is transmitted between the first impedance tube 3, the measured air-conditioning duct 8, and the second impedance tube 9. According to the sound pressure data measured by the four microphones, the incident wave , the reflected wave of the first impedance tube 3, the transmitted wave , and the reflected wave of the second impedance tube 9 can be obtained. The above signals satisfy the following transfer matrix: ; in, , , , represents the elements in the transfer matrix, for In the state, the reflected wave of the first impedance tube 3, according to the definition of transmission loss, when the end of the second impedance tube 9 is a non-reflection end (i.e. ), based on the incident wave and transmitted wave The ratio determines the transmission loss.

[0028] At the same time, due to hour, , therefore, we get the following relationship: ; For the two load modes (non-reflection end and rigid reflection end) at the end of the second impedance tube 9, the following two equations are obtained: Equation 1: ; Equation 2: ; Combining the above two equations, we can find: ; Therefore, the calculation formula for transmission loss is: .

[0029] In an exemplary embodiment of the present application, the signal processor is further configured to: The adjustment parameter is determined based on the reflection coefficient of the sound absorbing material, and the adjustment parameter and the reflection coefficient are negatively correlated; The transmission loss is corrected based on the adjustment parameters.

[0030] In this embodiment, in the first state, the sound absorbing material is theoretically required to completely absorb the sound wave (reflection coefficient γ=0) to simulate a "no reflection" environment. In actual testing, if the sound absorption coefficient of the sound absorbing material is insufficient (especially in the low frequency band), a residual reflected wave will remain at the end of the second impedance tube 9, and the residual reflected wave will propagate in the reverse direction and will be opposite to the incident wave. and transmitted wave The superposition forms a standing wave, making the incident wave and transmitted wave Deviates from the true value (too large), resulting in deviation in the calculation of transmission loss.

[0031] To solve the above problems, in this embodiment, the transmission loss is corrected by setting adjustment parameters. Specifically, considering that the magnitude of the residual reflected wave is mainly related to the reflection coefficient of the sound-absorbing material, the larger the reflection coefficient of the sound-absorbing material, the larger the residual reflected wave. At the same time, considering the attenuation effect of the measured air-conditioning duct 8 on sound waves, the influence degree of the residual reflected wave on the incident wave is less than that on the transmitted wave , that is, the deviation degree of the transmitted wave from the true value is greater. According to the above calculation formula of the transmission loss , the residual reflected wave will cause the absolute value of the calculated transmission loss to be too large.

[0032] Therefore, in this embodiment, the adjustment parameters are first determined based on the reflection coefficient of the sound-absorbing material. The larger the reflection coefficient, the smaller the adjustment parameter, so as to offset the influence of the residual reflected wave.

[0033] It can be concluded from the above that this embodiment takes into account the influence of the end reflection of the second impedance tube 9 on the calculation of the transmission loss, determines the corresponding adjustment parameters based on the reflection coefficient of the sound-absorbing material, corrects the transmission loss, and makes the calculation result of the transmission loss more accurate.

[0034] In an exemplary embodiment of the present application, the signal processor is specifically further configured to: Determine a proportional parameter based on the reflection coefficient of the sound-absorbing material; Determine an adjustment parameter based on the reflection coefficient of the sound-absorbing material and the proportional parameter.

[0035] In this embodiment, considering that the reflection coefficients of different sound-absorbing materials are different and the influence degrees on the transmission loss are different, this embodiment sets a proportional parameter to quantify the influence of the reflection coefficient of the sound-absorbing material on the transmission loss.

[0036] Specifically, determining the proportional parameter based on the reflection coefficient of the sound-absorbing material can be described in detail as follows: If the reflection coefficient of the sound-absorbing material is less than the first threshold, the proportional parameter is determined as the first value; If the reflection coefficient of the sound-absorbing material is between the first threshold and the second threshold, the proportional parameter is determined as the second value; If the reflection coefficient of the sound-absorbing material is greater than the second threshold, the proportional parameter is determined as the third value; the first threshold is less than the second threshold, and the first value, the second value, and the third value increase in sequence.

[0037] In this embodiment, when the reflection coefficient of the sound-absorbing material is less than the first threshold (for example, 0.2), it can be considered that the sound-absorbing material completely absorbs sound waves, there is no reflected wave at the end of the second impedance tube 9, and the corresponding proportional parameter can be set to 0.

[0038] When the reflection coefficient of the sound-absorbing material is between the first threshold and the second threshold (e.g., 0.5), the residual reflected wave energy cannot be ignored. At this time, the proportional parameter can be set to a smaller second value (e.g., 0.1).

[0039] When the reflection coefficient of the sound-absorbing material is greater than the second threshold (e.g., 0.7), the performance of the sound-absorbing material is poor and the residual reflected wave energy is high. At this time, the proportional parameter can be set to a larger third value (e.g., 0.5).

[0040] On this basis, determining the adjustment parameter based on the reflection coefficient of the sound-absorbing material and the proportional parameter may include: Calculating the adjustment parameter through the second formula, and the second formula is: ; Wherein, represents the adjustment parameter, represents the proportional parameter, represents the reflection coefficient of the sound-absorbing material.

[0041] Finally, the corrected transmission loss is: ; It can be concluded from the above that in this embodiment, the corresponding proportional parameter is determined based on the reflection coefficient of the sound-absorbing material, realizing the dynamic correction of the transmission loss, and further improving the accuracy of the transmission loss calculation.

[0042] In an exemplary embodiment of the present application, a test hole 5 is provided on the tube wall of the first impedance tube 3, and the microphone is arranged in the test hole 5.

[0043] In this embodiment, a test hole 5 can be provided on the tube wall of the first impedance tube 3, and the corresponding microphone is fixed in the test hole 5 to realize the fixation of the microphone on the first impedance tube 3. The signal acquisition end of the microphone is located inside the first impedance tube 3 and is used to measure the sound pressure signal inside the first impedance tube 3. The output end of the microphone is connected to the data collector 12 to send the detected data to the data collector 12.

[0044] Similarly, a test hole 5 can also be provided on the tube wall of the second impedance tube 9, and the corresponding microphone is fixed in the test hole 5 to realize the fixation of the microphone on the second impedance tube 9. The signal acquisition end of the microphone is located inside the second impedance tube 9 and is used to measure the sound pressure signal inside the second impedance tube 9. The output end of the microphone is connected to the data collector 12 to send the detected data to the data collector 12.

[0045] The above method for arranging the microphone is simple to operate and easy to implement.

[0046] In an exemplary embodiment of the present application, the number of microphones provided on the wall of the first impedance tube 3 is two, and the number of test holes 5 provided on the wall of the first impedance tube 3 is at least two.

[0047] In this embodiment, two microphones (including the first microphone 4 and the second microphone 6) are provided on the wall of the first impedance tube 3. The corresponding number of test holes 5 can be more than two. The multiple test holes 5 are arranged in a straight line on the first impedance tube 3. By setting the microphones in different test holes 5, the positions of the microphones can be changed, which is convenient for testing multiple groups of data.

[0048] Similarly, two microphones (including the third microphone 10 and the fourth microphone 11) are provided on the wall of the second impedance tube 9. The corresponding number of test holes 5 can be more than two. The multiple test holes 5 are arranged in a straight line on the second impedance tube 9. By setting the microphones in different test holes 5, the positions of the microphones can be changed, which is convenient for testing multiple groups of data.

[0049] It should be noted that if there is no microphone in a certain test hole 5, the test hole 5 needs to be blocked to avoid the leakage of acoustic wave signals and affect the test results.

[0050] In an exemplary embodiment of the present application, the air duct acoustic test device further includes: For the measured air ducts 8 with different apertures, the distances between the test holes 5 are different.

[0051] In this embodiment, for the measured air ducts 8 with different apertures, the distances between the multiple test holes 5 are different to ensure different limited frequency bandwidths. For example, according to the measured air ducts 8 with different apertures, the distances between the test holes 5 can be set to 20 mm or 50 mm respectively.

[0052] In an exemplary embodiment of the present application, both between the first impedance tube 3 and the measured air duct 8 and between the second impedance tube 9 and the measured air duct 8 are connected through a test tooling 7.

[0053] In this embodiment, one end of the test tooling 7 connected to the first impedance tube 3 is designed to be circular according to the actual size of the first impedance tube 3, and one end of the test tooling 7 connected to the measured air duct 8 is designed to be square according to the actual size of the measured air duct 8; one end of the test tooling 7 connected to the second impedance tube 9 is designed to be circular according to the actual size of the second impedance tube 9, and one end of the test tooling 7 connected to the measured air duct 8 is designed to be square according to the actual size of the measured air duct 8; the length of the test tooling 7 is greater than or equal to 6 times the diameter of the impedance tubes (the first impedance tube 3 and the second impedance tube 9) to avoid the problem of result error caused by the tooling during the test.

[0054] It can be concluded from the above that in this embodiment, by setting up the test tooling 7, reliable connections are achieved between the first impedance tube 3 and the air duct of the air conditioner under test 8, and between the second impedance tube 9 and the air duct of the air conditioner under test 8.

[0055] In an exemplary embodiment of the present application, a power amplifier 1 is provided between the first output end of the data collector 12 and the sound source.

[0056] In this embodiment, the power amplifier 1 is used to receive the voltage signal output by the data collector 12 and amplify this voltage signal to achieve reliable driving of the sound source.

[0057] In an exemplary embodiment of the present application, the air duct acoustic testing device further includes: A test chamber 14; wherein, the first impedance tube 3, the second impedance tube 9, the microphone, the data collector 12, and the signal processor are all arranged in the test chamber 14.

[0058] In this embodiment, the test chamber 14 is an anechoic chamber, ensuring that the ambient background noise is not greater than 25 dB(A), which is conducive to improving the test accuracy.

[0059] Referring to Figure 2 , based on the above testing device, the following steps can be adopted for air duct acoustic testing of the air conditioner: (1) Fix the power amplifier 1 and the data collector 12 on the bench, and place the four microphones in the test holes 5; (2) Start the power amplifier 1, and after the sound source signal is stable, set the range and the test frequency range; (3) Conduct microphone amplitude calibration to obtain an accurate microphone sensitivity value; form a non-reflective end at the end of the second impedance tube 9, and conduct amplitude mismatch and phase amplitude calibration between the microphones; conduct phase amplitude calibration using the microphone and the data collector 12; (4) Connect the test tooling 7 to the first end and the second end of the air duct of the air conditioner under test respectively, connect the first impedance tube 3 and the second impedance tube 9 to the corresponding test tooling 7, form a rigid end and a non-reflective end at the end of the second impedance tube 9 respectively, and use the double-load method for testing to obtain test data; (5) Upload the test data to the signal processing software 13, and the signal processing software 13 calculates the transmission loss according to the first formula; (6) The above testing steps can be used to obtain a transmission loss curve, as Figure 3 shown. This transmission loss curve is used to show the variation of the transmission loss with frequency. Among them, the horizontal axis represents the frequency of the acoustic wave signal, and the vertical axis represents the transmission loss corresponding to each frequency.

[0060] The above is only the specific implementation manner of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present application can easily think of various equivalent modifications or substitutions, and these modifications or substitutions should all be covered within the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. An air-conditioning duct acoustic testing device, characterized in that, It includes a first impedance tube, a second impedance tube, a microphone, a data collector, and a signal processor; A sound source is provided at the first end of the first impedance tube. The first output end of the data collector is used to output a voltage signal to drive the sound source to output a sound wave signal. The second end of the first impedance tube is used to connect to the first end of the air duct of the air conditioner to be measured. The first end of the second impedance tube is used to connect to the second end of the air duct of the air conditioner to be measured. The microphone is provided on the wall or inside of each of the first impedance tube and the second impedance tube; The output end of the microphone is connected to the signal input end of the data collector, and the second output end of the data collector is connected to the signal input end of the signal processor. The signal processor is used for: Based on the output data of the microphone in the first state and the output data of the microphone in the second state, calculate the transmission loss of the air duct of the air conditioner to be measured to obtain the acoustic test result of the air duct of the air conditioner to be measured; Wherein, in the first state, an acoustic absorption material is provided at the second end of the second impedance tube, and in the second state, no acoustic absorption material is provided at the second end of the second impedance tube.

2. The air-conditioning duct acoustic testing device according to claim 1, characterized in that, The microphone includes a first microphone, a second microphone, a third microphone, and a fourth microphone; the first microphone and the second microphone are provided on the wall or inside of the first impedance tube, and the third microphone and the fourth microphone are provided on the wall or inside of the second impedance tube; Specifically, the signal processor is used for: Calculate the transmission loss of the air duct of the air conditioner to be measured through a first formula; the first formula is: ； Among them, ; ； ； ； in, is the transmission loss, is the transmission coefficient, , , , They are The sound pressure data measured by four microphones in the state, or 2, Indicates the first state, Indicates the second state, , are the distances from the first microphone and the second microphone to the first end face of the tested air conditioning duct, respectively. , are the distances from the third microphone and the fourth microphone to the second end face of the tested air conditioning duct, respectively. for The incident wave in the state, for The transmitted wave in the state, for The reflected wave of the second impedance tube in the state, represents the wave number of the sound wave signal, Is the imaginary part.

3. The air-conditioning duct acoustic testing device according to claim 2, characterized in that, The signal processor is further used for: Determine an adjustment parameter based on the reflection coefficient of the acoustic absorption material, and the adjustment parameter and the reflection coefficient have a negative correlation relationship; Correct the transmission loss based on the adjustment parameter.

4. The air-conditioning duct acoustic testing device according to claim 3, wherein, The signal processor is further used for: Determine a proportional parameter based on the reflection coefficient of the acoustic absorption material; Determine the adjustment parameter based on the reflection coefficient of the acoustic absorption material and the proportional parameter.

5. The air-conditioning duct acoustic testing device according to claim 1, characterized in that A test hole is provided on the wall of the first impedance tube, and the microphone is provided in the test hole.

6. The air-conditioning duct acoustic testing device according to claim 5, characterized in that, The number of microphones provided on the wall of the first impedance tube is two, and the number of test holes provided on the wall of the first impedance tube is at least two.

7. The air-conditioning duct acoustic testing device according to claim 6, characterized in that, It further includes: For the air duct of the air conditioner to be measured with different apertures, the distance between the test holes is different.

8. The air-conditioning duct acoustic testing device according to claim 1, characterized in that, Both between the first impedance tube and the air duct of the air conditioner to be measured, and between the second impedance tube and the air duct of the air conditioner to be measured are connected through a test tooling.

9. The air-conditioning duct acoustic testing device according to claim 1, wherein, A power amplifier is provided between the first output end of the data collector and the sound source.

10. The air-conditioning duct acoustic testing device according to claim 1, characterized in that, It further includes: A test chamber; wherein, the first impedance tube, the second impedance tube, the microphone, the data collector, and the signal processor are all provided in the test chamber.

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