JP2011179966A - Sound sensitivity measuring apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sound sensitivity measuring apparatus for preventing the accuracy from being degraded by the directivity of a sound source, and correctly measuring the sound sensitivity in an intermediate frequency band. <P>SOLUTION: The sound sensitivity measuring apparatus includes the sound source attached to a rotatable fixing member disposed within a cab, and rotated along with the rotated fixing member; a sound pressure sensor for detecting sound pressure by a sound emitted from the sound source; an acceleration sensor provided on the surface of the cab and detecting an acceleration by the sound; and a sound sensitivity calculation means for calculating the sound sensitivity from the sound pressure and the acceleration. The sound sensitivity calculation means calculates the sound sensitivity from the sound pressure and the acceleration obtained by the sound emitted from the sound source at each rotation position. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to an acoustic sensitivity measuring apparatus, and more specifically to an acoustic sensitivity measuring apparatus that measures acoustic sensitivity in a relatively narrow closed space such as a passenger compartment.

  Conventionally, when measuring the sensitivity from multi-point input, a method of reducing the number of measurements by using the reciprocity theorem and vibrating the response side instead of the input side is known. For example, when measuring acoustic sensitivity using the reciprocity theorem, sound is input into a room from a sound source such as a speaker placed on the response side, and vibrations at each point on the input side are actually measured.

  In the acoustic sensitivity measuring device of Patent Document 1, a sound source arranged in a seat in a cab (cabinet unit), one unidirectional sound source side acceleration detection means installed in the sound source, and four cab mount points. The acoustic sensitivity is measured using acceleration detection means on the cab mount side in three directions.

JP 2007-327908 A

  However, in the acoustic sensitivity measuring apparatus of Patent Document 1, since the sound source is directed in one direction fixed to the seat, in the medium frequency band of about 200 Hz to 500 Hz, the directivity of the sound source and the size of the speaker used as the sound source are large. There is a problem that measurement cannot be performed with high accuracy.

  An object of the present invention is to solve the problem of accuracy degradation due to the directivity of the sound source, and particularly to accurately measure the acoustic sensitivity in the middle frequency band.

  The present invention provides an acoustic sensitivity measuring apparatus. The acoustic sensitivity measuring device is attached to a rotatable fixing member disposed in a cab, and a sound source that rotates as the fixing member rotates, a sound pressure sensor that detects sound pressure due to sound emitted from the sound source, and a surface of the cab Provided with an acceleration sensor for detecting acceleration due to sound and acoustic sensitivity calculation means for calculating acoustic sensitivity from the sound pressure and acceleration, the acoustic sensitivity calculation means being obtained under the sound emitted by the sound source at each rotational position. The acoustic sensitivity is calculated from the sound pressure and acceleration.

  According to the present invention, since the acoustic sensitivity can be obtained while changing the direction of the sound source, it is possible to improve the decrease in accuracy of the acoustic sensitivity measurement due to directivity without preparing a plurality of sound sources.

  According to one aspect of the present invention, the sound pressure sensor is attached to the fixed member, rotates with the sound source, and detects the sound pressure at a predetermined distance in front of the sound source.

  According to one aspect of the present invention, since the sound pressure at a predetermined position before the sound source can be measured continuously, the acoustic sensitivity can be obtained stably and accurately regardless of the rotation angle of the sound source.

  According to one aspect of the present invention, it further includes an angle sensor that detects the rotation angle of the sound source and a control device that controls the input voltage of the sound source, and the control device applies at least one of the rotation angle and the sound pressure of the sound source. Change the input voltage of the sound source accordingly.

  According to one aspect of the present invention, since the input voltage of the sound source can be adjusted according to at least one of the rotation angle and sound pressure of the sound source, the volume acceleration that the sound receives even if the direction of the sound source is changed It is possible to suppress a situation in which it is difficult to keep the S / N ratio of the signal constant due to a change due to or a vibration level at the acceleration detection point significantly changing.

  According to an aspect of the present invention, the sound generator further includes a noise generator that sends a noise signal that is an input signal of the sound source to the control device, and the acoustic sensitivity calculation unit is configured to input sound pressure when the sound source emits sound based on the noise signal. Then, the acoustic sensitivity is calculated until the rate of change of acceleration is equal to or less than a predetermined value.

  According to one aspect of the present invention, even when a noise signal such as white noise is used, it is not necessary to correct motor noise accompanying acoustic rotation, Doppler effect of acoustic acceleration, etc., and to obtain acoustic sensitivity with high accuracy. Is possible.

  According to an aspect of the present invention, the sound source includes a speaker, a housing that extends in a horizontal direction and supports a substantially horizontal rotation shaft of the speaker, a first motor that rotates the housing around a substantially vertical rotation shaft, And a second motor for rotating the speaker around a substantially horizontal rotation axis, the speaker having a flat portion provided at an axial end portion of the substantially horizontal rotation shaft, the flat portion and the housing, In the meantime, the drive unit driven by the second motor is supported coaxially with the substantially horizontal rotation axis of the speaker.

  According to one aspect of the present invention, the speaker as the sound source can rotate about the substantially horizontal rotation axis and the substantially vertical rotation axis, so that the direction of the sound source can be freely changed according to the measurement environment, and more accurate. It becomes possible to measure the acoustic sensitivity well.

It is a figure for demonstrating the measurement principle (method) of this invention. It is a figure which shows the structure of the acoustic sensitivity measuring apparatus of one Embodiment of this invention. It is a figure which shows the example of arrangement | positioning of the sound source of one Embodiment of this invention. It is a figure which shows the mode of rotation of the sound source of one Embodiment of this invention. It is a figure which shows the relationship between the frequency | count which takes the average of measurement data, and a data error. It is a figure which shows the acoustic sensitivity measurement flow of one Embodiment of this invention. It is a figure which shows the structure of the sound source of one Embodiment of this invention.

  Embodiments of the present invention will be described with reference to the drawings. First, the measurement principle (method) of the present invention will be described with reference to FIG.

  FIG. 1 is a diagram for explaining the measurement principle of the present invention. As shown in FIG. 1A, the acoustic sensitivity is calculated from the sound pressure (Pa) detected by the sound pressure sensor 1 at a response point when an input (N) is given to an input point, and the unit is ( Pa / N). Since the reciprocity theorem holds in acoustic sensitivity, the acoustic sensitivity can be obtained by measuring the response of the input point when an input is given to the sound pressure response point.

For example, as shown in FIG. 1B, a sound source 2 is placed at a response point, volume acceleration Av (m ³ / s ² ) is given as an input to sound, and the acceleration sensor 3 detects a response at the input point. An acceleration a (m / s ² ) is obtained. The acoustic sensitivity Rs ((m ³ / s ² ) / (m / s ² ) = (1 / m ² ) = (Pa / N))) can be obtained from the ratio (Av / a). That is, the acoustic sensitivity Rs can be obtained from the following equation.

In general, a sound source such as a speaker is used to input to sound. At this time, it is necessary to accurately know the volume acceleration Av (m ³ / s ² ) input to the sound. As a method of estimating the volume acceleration Av (m ³ / s ² ), for example, there are a method of estimating from the diaphragm of the sound source and a method of estimating from the sound pressure immediately before the diaphragm of the sound source. The former is adopted in Patent Document 1, and the volume acceleration Av (m ³ / s ² ) is calculated from the product of the vibration magnitude Pf (m / s ² ) of the diaphragm and the area S (m ² ) of the diaphragm. Obtained (Av = Pf × S (m ³ / s ² )).

In one embodiment of the present invention, the volume acceleration Av (m ³ / s ² ) is obtained using a method of estimating from the sound pressure immediately before the diaphragm of the latter sound source. The outline will be described below.

From D'Alembert's wave equation, the velocity potential Φ, sound pressure p, particle velocity v, and acceleration a of a certain sound field have the following relationship. Where ρ is density.

Here, the ratio z between the sound pressure p and the particle velocity v is referred to as acoustic impedance density.

In particular, in the case of a traveling plane wave, it has a value specific to the medium, and is called a specific acoustic impedance. It is known that the sound pressure immediately before the diaphragm of the sound source that is output when a normal random number signal is input to the sound source placed in the cab (cabin unit) is a traveling wave that is almost unaffected by the sound field. Yes. Therefore, the particle velocity v immediately before the diaphragm can be estimated from the sound pressure p immediately before the diaphragm using the following expression using this knowledge and the relationship of the expression (3).

Since the particle velocity a obtained by differentiating the particle velocity v is the particle acceleration a, the particle acceleration a can be obtained from the following equation using equation (4).

If the area through which the medium vibrated by the diaphragm passes is S and the unknown α is introduced, the volume acceleration Av can be obtained from the following equation using the acceleration a in equation (5).

Since a normal random number is given as an input to the sound source, the sound pressure p is obtained as a random signal. Since the signal obtained by differentiating the random signal is a random signal, the frequency characteristic FFT (variable) is the same (although the absolute value is different), and can be expressed as follows using the unknown β.

Therefore, the frequency characteristic FFT (Av) of the volume acceleration Av can be expressed as the following equation when the unknowns are combined into one as γ.

  This unknown γ is a unique value as long as the traveling wave assumption is satisfied and the relationship between the diaphragm and the sound pressure measurement position is constant, and can be obtained by measurement in advance. From the relationship of equation (8), it is possible to estimate the volume acceleration Av given to the medium using the sound pressure p immediately before the diaphragm. In the present invention, the acoustic sensitivity Rs is calculated from the above-described equation (1) using the volume acceleration Av thus obtained.

  FIG. 2 is a diagram showing a configuration of an acoustic sensitivity measuring apparatus according to an embodiment of the present invention. In this embodiment, it is assumed that acoustic sensitivity is measured in a cab (vehicle compartment unit) of a vehicle.

  The acoustic sensitivity measuring apparatus shown in FIG. 2 is attached to a rotatable fixing member 11 disposed in the cab 10, and detects a sound source 12 that rotates with the rotation of the fixing member 11 and a sound pressure due to sound generated by the sound source 12. A sound pressure sensor 13, an acceleration sensor 14 provided on the surface of the cab 10 for detecting acceleration due to sound, and an acoustic sensitivity calculation means 15 for calculating acoustic sensitivity from the sound pressure and acceleration are provided.

  The sound source 12 is rotated around the rotation shaft 24 together with the fixing member 11 by the motor 16. The motor 16 is formed of a stepping motor, for example, and rotates the sound source 12 at every predetermined step (angle) under the control of the rotation controller 17. The rotation angle is detected by the angle detector 18. The sound source 12 includes an arbitrary acoustic speaker such as a cone type speaker or a flat speaker. The output of the sound source 12 is varied by the power amplifier 19, and the output of the amplifier 19 is controlled by the amplifier controller 20. A noise generator 21 is connected to the amplifier 19. The noise generator 21 can generate an arbitrary noise signal such as a random number signal (white noise). The noise generator 21 is a random number generator, for example.

  The sound pressure sensor 13 is fixed to the fixing member 11 by a fixing tool 22 so as to rotate together with the sound source 12. At that time, the sound pressure sensor 13 is fixed to the fixing member 11 so as to be located at a predetermined distance from the surface of the sound source 12. This is because the γ value of the above-described equation (8) is obtained as a constant value. The sound pressure sensor 13 is composed of a microphone, for example.

  The acceleration sensor 14 is composed of, for example, a uniaxial acceleration sensor, and detects vertical acceleration at the cab mount point. In addition, you may make it detect simultaneously the acceleration of 2 directions or 3 directions of the up-down direction, the front-back direction, or the left-right direction in a cab mount point using a 2-axis or 3-axis acceleration sensor.

  The detection signal of the sound pressure sensor 13 and the detection signal of the acceleration sensor 14 are input to the acoustic sensitivity calculation means 15 via the data collector 23. The data collector 23 includes a charge amplifier, a signal conditioner, etc. for amplifying and shaping the respective signals. The data collector 23 may be integrally configured as a part of the acoustic sensitivity calculation unit 15.

The acoustic sensitivity calculation means 15 includes a frequency analysis circuit such as FFT, for example. The acoustic sensitivity calculation means 15 calculates the acoustic sensitivity from the sound pressure and acceleration obtained under the sound emitted by the sound source 12 at each rotational position (angle). Specifically, while the sound source 12 is rotated by a predetermined angle unit, the volume acceleration Av is obtained at each angle using the received sound pressure p and the relationship of the above-described equation (8). Based on the obtained volume acceleration Av (m ³ / s ² ) and the received vibration acceleration a (m / s ² ), the acoustic sensitivity Rs ((1 / m ² ) = (Pa / N)) using the equation (1) Is calculated. At that time, the average value of the acoustic sensitivity Rs at each rotation angle (each direction) of the sound source is set as the acoustic sensitivity at the time of the measurement.

  The output of the sound pressure sensor 13 and the output of the angle detector 18 are input to the amplifier controller 20 and used for output control of the amplifier 19. The reason is as follows. Since the measurement is continuously performed at each rotational position (angle) while rotating the sound source 12, the measurement level at the reference point (sound pressure measurement point) or response point (acceleration measurement point) depends on the direction of the sound source 12. It will be different. As a result, the range of measurement may change, and it is predicted that overload or underload will occur.

  The accuracy is improved by adjusting the sound pressure level range each time the direction of the sound source 12 is changed, but the measurement man-hour (time) is increased. Therefore, the output of the sound pressure sensor 13 is input to the amplifier controller 20 and output from the sound source 12 so that the level at the reference point (sound pressure measurement point) and response point (acceleration measurement point) is in an appropriate range. Feedback control of sound pressure level. Alternatively, the relationship between the sound pressure level and the rotation angle is obtained in advance and stored in the memory of the amplifier controller 20, and the relationship is referred to so that feedback control is performed from the output (angle) of the angle detector 18. Instead, the above sound pressure level adjustment may be realized.

  FIG. 3 is a top view showing an example of arrangement of sound sources according to an embodiment of the present invention. The vehicle 30 includes a trunk room 31 and a passenger compartment 32 having front seats 33 and 34 and a rear seat 35. The sound source 35 is installed in the front seat 33 in front of the handle 36. In this case, according to the reciprocity theorem, the acoustic sensitivity near the position of the driver, more precisely near the position of the driver's ear, is obtained. The sound source 35 can be placed at an arbitrary position to be measured. For example, if the sound source 35 is installed in the front seat 34, it is possible to obtain the acoustic sensitivity that a passenger sitting in the seat will hear.

  FIG. 4 is a diagram illustrating a state of rotation of the sound source according to the embodiment of the present invention. FIG. 4 shows only the periphery of the front seats 33 and 34 of FIG. (A) is an example when a cone-type speaker is used as the sound source 35. (B) is an example when a flat speaker is used as the sound source 35.

  In FIG. 4A, the cone type speaker of the sound source 35 can be regarded as one point sound source 38, and the sound spreads with the distance, and the attenuation of the sound pressure with the distance increases. By rotating the sound source 35, a spherical wave (respiratory sphere) can be simulated from the plane wave output from the sound source 35. At that time, a finer rotation angle (rotation step) of one step is closer to a spherical wave, but the number of measurements increases, leading to an increase in the number of measurement steps. Conversely, if the rotation step is too small, it cannot be captured as a spherical wave, leading to a decrease in accuracy. In order to ensure accuracy up to a medium frequency (up to 500 Hz), it is desirable that the rotation step θ is performed at about 15 degrees or less (equivalent to a regular dodecagon) or more as shown in the figure.

In FIG. 4B, the plane speaker of the sound source 35 is a plane sound source whose entire surface vibrates in the same direction, and the generated sound is a plane wave. There is little spread of sound due to distance, and there is little attenuation of sound pressure due to distance. In this case, if the width of the plane wave coming out of the speaker 35 (≈the width of the speaker) is d and the distance from the front surface of the speaker 35 to the wall surface of the passenger compartment 32 is r, as shown in the figure, the rotation step θ is For example, the following equation can be obtained.

  In one embodiment of the present invention, a normal random signal is used as the output of the noise generator 21, that is, the input of the amplifier 19. The reason is as follows. When measuring the frequency response over the entire measured frequency band, there are a method of inputting an impulse signal and a method of inputting a signal obtained by sweeping a sine wave. Generally, excitation (input) to a sound source is performed.

  White noise is a random wave having a constant amplitude with respect to frequency, and a normal random number is used in engineering. As a feature of normal random numbers, an average over a certain period of time can be regarded as white noise, so it is necessary to wait until the measurement result is stabilized (converged).

  FIG. 5 is a diagram showing the relationship between the number of times of averaging data and the data error (dB). As shown in the graph of FIG. 5, a certain average number of times (about 20 in the example of FIG. 5) is required until the error is reduced. In addition, since it is a random signal, it does not always become a graph like FIG. Therefore, the measurement at each rotation step of the sound source is controlled to proceed to the next rotation step after entering the specified number of consecutive times within an error range with an average change or after performing the averaging process more than the specified number of times. I do. In other words, it is desirable to calculate the acoustic sensitivity or the like until the rate of change of the sound pressure and the acceleration becomes a predetermined value or less.

In one embodiment of the present invention, rotation may become excessive depending on measurement conditions. In that case, weighting is performed by averaging the excess amount so that the average of the acoustic sensitivity for one round (360 degrees) is obtained. If the acoustic sensitivity measured at the i-th time is Rsi and the weight is Ai, the average acoustic sensitivity Rs can be obtained by the following equation.

FIG. 6 is a diagram showing an acoustic sensitivity measurement flow according to an embodiment of the present invention. The following description is based on the configuration example of FIG. In step S1, the rotation angle of the sound source 12 is set. An initial value θ ₀ , a final predetermined angle θ _n and an angle Δθ of one rotation step are set. The rotation angle of the sound source 12 is stepped every Δθ from the initial value θ ₀ to the predetermined angle θ _n . In step S2, the rotation angle of the sound source is detected. As described above, this detection signal is used for the rotation control 17 of the motor 16 and the control of the amplifier 19 of the sound source.

  In step S <b> 3, a noise signal such as a normal random number is output from the noise generator 21 to the amplifier 19 of the sound source 12. In step S4, the output voltage of the amplifier 19 is set. The sound source 12 outputs a sound (sound) corresponding to a noise signal having a predetermined magnitude (amplitude) input from the amplifier 19.

  In step S5, it is determined whether or not the sound pressure detected by the sound pressure sensor 13 is a predetermined signal level. The reason is that, as already explained, the signal level (range) of the detected sound pressure and acceleration is within an appropriate range. If this determination is No, the process returns to step S4, and the output voltage of the amplifier 19 is reset. When this determination is Yes, the process proceeds to step S6, where the sound pressure signal (data) detected by the sound pressure sensor 13 and the acceleration signal (data) detected by the acceleration sensor 14 are collected by the data collector 23.

In step S7, the acoustic sensitivity calculation means 15 calculates the volume acceleration Av (m ³ / s ² ) and the acoustic sensitivity Rs (Pa / N) based on the collected data. In the calculation, as described with reference to FIG. 5, the final calculation result is obtained after the measurement result is stable, that is, the data error (dB) is within a predetermined error range.

In step S8, the rotation angle of the sound source it is determined whether or not the last of a predetermined angle theta _n. If this determination is No, the process returns to step S1, the rotation angle of the sound source is stepped one step, the next rotation angle is set, and step S2 and subsequent steps are repeated. If this determination is Yes, the measurement is terminated.

  In the embodiment described above, the case where sound measurement is performed while rotating the sound source around a substantially vertical rotation axis (for example, 11 in FIG. 2) has been described. However, as a form of the sound source of the present invention, for example, as shown in FIG. 7, a sound source that can rotate around a substantially horizontal rotation axis as well as a substantially vertical rotation axis may be used. In that case, the sound source speaker can rotate around a substantially horizontal rotation axis and a substantially vertical rotation axis, so the direction of the sound source can be freely changed according to the measurement environment, and the acoustic sensitivity can be measured more accurately. It becomes possible.

  FIG. 7 is a diagram showing a configuration of a sound source according to an embodiment of the present invention. (A) of FIG. 7 is the figure which looked at the sound source from diagonally forward, (b) is the figure seen from diagonally backward. In FIG. 7, the speaker 40 is installed in a housing 41. The housing 41 extends in the horizontal direction and supports a substantially horizontal rotating shaft 42 of the speaker 40. The speaker 40 has flat portions 43 at two end portions in the axial direction of the substantially horizontal rotation axis. A driving unit 45 driven by the second motor 44 is supported coaxially with the substantially horizontal rotating shaft 42 of the speaker 40 between the flat portion 43 and the housing 41. The drive unit 45 transmits the rotational force of the second motor 44 to the substantially horizontal rotation shaft 42 of the speaker 40 by the belt 46. Due to the rotational force of the second motor 44, the speaker 40 rotates around a substantially horizontal rotation shaft 42.

  Further, a first motor 48 that rotates the housing 41 around a substantially vertical rotation shaft 47 is provided on the lower side of the housing 41, and the speaker 40 together with the housing 41 is provided by the rotational force of the first motor 48. It rotates around a substantially vertical rotating shaft 47. As in the case of the sound source 12 shown in FIG. 2 described above, the speaker 40 rotates while rotating about a predetermined rotation step (angle Δθ) around a substantially horizontal rotation shaft 42 and a substantially vertical rotation shaft 47. The cone 49 is vibrated at a position (angle) to output sound.

  As described above, according to the embodiment of the sound source of FIG. 7, since the speaker as the sound source can rotate around the substantially horizontal rotation axis and the substantially vertical rotation axis, the direction of the sound source can be freely changed according to the measurement environment. Therefore, it is possible to measure the acoustic sensitivity with higher accuracy.

Finally, the effects according to the embodiment of the present invention are listed below.
(1) Since the direction of the sound source can be easily changed and a plurality of sound sources (cones) are not required, the cost for measurement can be reduced.
(2) The acoustic sensitivity calculation means measures the volume acceleration received by the sound and the acceleration of the response point, and when obtaining the acoustic sensitivity from the quotient thereof, the diaphragm is regarded as a rigid body and represents the acceleration at a certain point, Volume acceleration is calculated. However, in the measurement at a medium frequency or higher, the vibration plate may not be assumed to be a rigid body, and it is difficult to obtain the volume acceleration received by the sound from the acceleration of the sound source as in the conventional case. Therefore, in the present invention, the difficulty is overcome by measuring the sound pressure by a sound pressure sensor installed immediately before the sound source, calculating the volume acceleration as needed, and obtaining the acoustic sensitivity by obtaining the quotient with them.
(3) Since the place where the sound source is installed is the position of each passenger's ear, it is greatly deviated from the center point in the passenger compartment, and the distance from the front of the sound source to the wall surface is not constant. Therefore, the volume acceleration received by the sound changes depending on the direction of the sound source, the vibration level at the acceleration detection point changes significantly, and it becomes difficult to keep the signal S / N ratio constant. Therefore, feedback control is performed according to the output level of the sound pressure sensor used to calculate the volume acceleration, and the signal input to the sound source is controlled to suppress changes in the S / N ratio and range of the signal. can do. Further, it is possible to continuously perform measurement without having to adjust the output range of the sensor every time the direction of the sound source is changed.
(4) A normal random number signal (white noise) is input to the sound source in order to input a uniform volume acceleration in the entire frequency range. Since white noise requires a certain amount of time to converge, the sound source is rotated by a stepping motor, and the direction is changed after the measurement data converges. This eliminates the need for correction of the motor noise accompanying rotation and the Doppler effect of acoustic acceleration.

  The above-described embodiment is an example, and the present invention is not limited to this. The present invention is applicable not only to the interior of a vehicle but basically to acoustic sensitivity measurement in an arbitrary closed space.

Claims (5)

A sound source that is attached to a rotatable fixing member disposed in the cab and rotates with the rotation of the fixing member;
A sound pressure sensor for detecting sound pressure due to sound emitted from the sound source;
An acceleration sensor provided on the surface of the cab and detecting acceleration due to the sound;
Acoustic sensitivity calculating means for calculating acoustic sensitivity from the sound pressure and the acceleration,
The acoustic sensitivity calculation means calculates acoustic sensitivity from the sound pressure and acceleration obtained under the sound emitted by the sound source at each rotational position.
Acoustic sensitivity measuring device.   The acoustic sensitivity measuring apparatus according to claim 1, wherein the sound pressure sensor is attached to the fixing member, rotates with the sound source, and detects a sound pressure at a predetermined distance in front of the sound source. An angle sensor for detecting a rotation angle of the sound source;
A control device for controlling the input voltage of the sound source,
The acoustic sensitivity measuring device according to claim 1, wherein the control device changes the input voltage according to at least one of a rotation angle of the sound source and the sound pressure. A noise generator for sending a noise signal to be input to the sound source to the control device;
The acoustic sensitivity calculation means calculates the acoustic sensitivity until the change rate of the input sound pressure and acceleration is equal to or lower than a predetermined value when the sound source emits sound based on the noise signal. The acoustic sensitivity measuring apparatus in any one. The sound source is
Speakers,
A housing extending in a horizontal direction and supporting a substantially horizontal rotation shaft of the speaker;
A first motor that rotates the housing about a substantially vertical axis of rotation;
A second motor for rotating the speaker around the substantially horizontal rotation axis;
The speaker has a flat portion provided at an axial end portion of the substantially horizontal rotation shaft, and a drive unit driven by the second motor is provided between the flat portion and the housing. The acoustic sensitivity measuring apparatus according to claim 1, wherein the acoustic sensitivity measuring apparatus is supported coaxially with a substantially horizontal rotation axis of the speaker.

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