JP2013148374A - Apparatus and method of measuring mechanical noise of headphone - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an apparatus and a method of measuring mechanical noise of a headphone, which can quantitatively evaluate mechanical noise that affects on a use feeling of a headphone.SOLUTION: An apparatus for measuring mechanical noise of a headphone includes: fixing means 1 for acoustically combining and fixing a headphone 2 and a microphone 3, support means 4 for supporting a part of a cable 2b or a plug in a state that no tension is applied to the cable 2b of the headphone 2; excitation means 5 for mechanically exciting the cable 2b between an attachment part of the headphone 2 in the fixing means 1 and the support means 4; and evaluation means 6 for evaluating an acoustic signal measured by the microphone 2.

Description

  The present invention relates to a measuring apparatus and a measuring method for measuring mechanical noise of headphones.

  In headphones, mechanical noise generated in a cable, so-called touch noise, may be detected as sound, and in the insert type, since the external auditory canal is sealed, it tends to cause discomfort as a loud sound. Cable touch noise occurs when a cable is touched or a cable hits another object. Mechanical noise is generated regardless of the electrical signal and greatly affects the feeling of use.

  In order to reduce touch noise, it is known that it is effective to turn the cable behind the ear when wearing headphones, or to attach a clip in the middle of the cable and fix it to clothes etc., for example, Patent Document No. 1 describes a method in which the bush is rotatable so that the protruding portion of the headphone cable is on the upper side, and the cable coming out of the bush is attached to the back of the auricle.

  By fixing a part of the cable, when the cable vibrates, the vibration is attenuated at the fixing portion, and touch noise can be reduced.

  Further, Patent Document 2 describes a headphone in which a member having elasticity is interposed at a connecting portion between a cable and a housing in order to prevent noise generated by propagation of vibration generated in the cable. ing.

JP 2011-77762 A JP 2011-77763 A

  As described above, since mechanical noise generated in headphones greatly affects the feeling of use, it has been proposed to reduce the vibration of the cable so that it does not propagate. However, the mechanical noise is quantitatively evaluated. No attempt has been made.

  The present invention has been proposed in view of the above, and an object of the present invention is to provide an apparatus for measuring mechanical noise of headphones that enables quantitative evaluation of mechanical noise that affects the feeling of use of the headphones. And providing a measuring method.

  In order to solve the above-described problem, the headphone mechanical noise measuring device according to the first aspect of the present invention includes a headphone 2 and a fixing means 1 for acoustically coupling and fixing the headphone 2 and the microphone 3; Supporting means 4 for supporting a part of the cable 2b or a plug without applying tension to the cable 2b of the headphone 2, and a cable between the mounting part of the headphone 2 in the fixing means 1 and the supporting means 4 A vibration means 5 for mechanically vibrating 2b; and an evaluation means 6 for evaluating an acoustic signal measured by the microphone 2 when the vibration means 5 vibrates the cable 2b. And

  According to a second aspect of the present invention, in the apparatus for measuring mechanical noise of a headphone according to the first aspect, the mounting portion on which the headphone 2 is mounted is made of an elastomer, and preferably has an audible frequency band of 20-20 KHz. The elastic modulus is 1 MPa or less.

  Further, according to a third aspect of the present invention, in the apparatus for measuring mechanical noise of headphones according to the first or second aspect, the vibration means 5 is a machine lower than a part of the headphone 2 to be vibrated. It has an impedance.

  Furthermore, in the method for measuring mechanical noise of headphones according to a fourth aspect of the present invention, the headphones 2 and the microphones 3 are acoustically coupled and fixed, and a part of a cable 2b or a plug of the headphones 2 is connected to the cable. 2b is supported in a state where no tension is applied, and the acoustic signal measured by the microphone 2 is mechanically vibrated between the mounting portion of the headphone 2 and a part of the cable 2b or the support portion 4 of the plug. It is characterized by evaluating.

  The invention according to claim 5 is the method for measuring mechanical noise of headphones according to claim 4, wherein the excitation source includes impulse, M-sequence, chirp or white noise, and the frequency characteristics of the excitation force are less uneven. It is characterized by that.

  The invention according to claim 6 is the method for measuring mechanical noise of headphones according to claim 4 or 5, wherein the A characteristic, B, C characteristic, or masking effect is considered for the obtained acoustic signal. An evaluation result is obtained by performing processing in consideration of an auditory characteristic including at least one of loudness.

  According to a seventh aspect of the present invention, in the method for measuring mechanical noise of headphones according to the sixth aspect, the evaluation result has a high correlation with a psychological experiment result.

  According to the first aspect of the present invention, the mechanical noise that affects the feeling of use of the headphones can be quantitatively evaluated by mechanically vibrating the cable and evaluating the acoustic signal measured by the microphone by the evaluation means. A measuring device is obtained which becomes possible.

  According to the second aspect of the present invention, the headphone mounting portion is made flexible so that it is close to the case where the headphone is worn on a person's auricle during actual use including the influence of mechanical vibration of the headphone itself. Close characteristics can be obtained.

  According to the third aspect of the present invention, the vibration transmitted from the vibrating means to the headphones can be reduced by making the mechanical impedance of the vibrating means lower than that of a part of the headphone to be excited. The influence on the measured value by the vibration means can be reduced.

  Furthermore, according to the present invention, the mechanical noise that affects the feeling of use of the headphones can be quantitatively evaluated by mechanically vibrating the cable and evaluating the acoustic signal measured by the microphone. A possible measurement method is obtained.

  In this invention of Claim 5, the precision of a measured value can be raised except the influence of the frequency characteristic of an excitation source.

  In this invention of Claim 6, the evaluation result close | similar to the magnitude of the sound which a person feels can be obtained by performing the process which considered the auditory characteristic with respect to the acoustic signal.

  In this invention of Claim 7, it has a high correlation with a psychological experiment result, and the measurement result close | similar to the usability of headphones is guaranteed.

It is a figure which shows schematic structure of the measurement apparatus of the mechanical noise of the headphones which concerns on the Example of this invention. It is a figure which shows the relationship between the magnitude | size of the mechanical noise in a psychological experiment, and the measured value by the measuring apparatus of this invention. 4 is a flowchart illustrating a method for measuring mechanical noise of headphones according to an embodiment of the present invention.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a diagram showing a schematic configuration of a headphone mechanical noise measuring apparatus according to an embodiment of the present invention. This measuring apparatus includes a headphone mounting portion (fixing means) 1, a support portion (support means) 4, an excitation source (excitation means) 5, an evaluation device (evaluation means) 6, and the like. The headphone mounting unit 1 and the support unit 4 are mounted and installed on a stand (not shown), for example.

  A microphone 3 is mounted on the headphone mounting unit 1 in advance, and the ear chip 2a of the headphone 2 to be measured is inserted into the headphone mounting unit 1 for mounting, and the headphone 2 and the microphone 3 are acoustically coupled. To be fixed. The headphone wearing section 1 is made of, for example, an elastomer, and preferably has an elastic modulus of 1 MPa or less in an audible band with a frequency of 20 to 20 KHz, and can be measured in a state close to that when worn on a human auricle. Further, by forming the headphone mounting portion 1 from a flexible material, it is possible to obtain characteristics close to those in actual use including the influence of mechanical vibration of the headphones 2 themselves.

  The support portion 4 supports a part (or plug) of the cable 2b in a state where no tension is applied to the cable 2b of the headphones 2. The headphone mounting portion 1 and the support portion 4 of the cable 2b are mechanically vibrated by the vibration source 5. A pendulum or a spring may be used as the excitation source 5 and the cable may be hit with a fixed force.

  That is, the cable 2b is vibrated by swinging the pendulum with an appropriate amplitude and bringing the pendulum into contact with the cable 2b at an appropriate position. Since the vibration generated by the impact is pulsed, the unevenness of the frequency characteristics can be suppressed to a small level.

  Here, by making the mechanical impedance of the vibration source 5 lower than a part of the headphone 2 that is the vibration target, the same level of vibration can be realized regardless of the type of the headphones, and the measured value based on the vibration characteristics Can be reduced. For example, a pendulum using a weight that is sufficiently lighter than the weight of the cable 2b may be used for the thread that is sufficiently lighter than the weight. Since there are few unevenness | corrugations of the frequency characteristic of the vibration source 5, the accuracy of a measured value can be raised except the influence on the frequency characteristic of the vibration source itself.

  When the vibration source 5 vibrates the cable 2b, the acoustic signal measured by the microphone 3 is input to the evaluation device 6 and the mechanical noise of the headphones 2 is measured. That is, an acoustic signal obtained from the microphone 3 is taken into an evaluation device 6 such as a personal computer, and an A characteristic, a B characteristic, a C characteristic, or a loudness such as a loudness in consideration of a masking effect according to a predetermined evaluation algorithm. Performs processing considering characteristics and obtains evaluation results. This evaluation result has a high correlation with the psychological experiment result as shown in FIG. 2 by the process considering the auditory characteristics.

  FIG. 2 shows the relationship between the magnitude of mechanical noise in a psychological experiment and the measured value using the measuring apparatus according to the present invention. As shown in the figure, the measured value increases as the mechanical noise increases, and the regression line by the least square method becomes as shown by a broken line, and the correlation coefficient may be as high as about 0.9. I understand.

  Next, a method for measuring the mechanical noise of the headphones according to the embodiment of the present invention will be described in detail with reference to the flowchart of FIG. First, the headphone 2 and the microphone 3 are acoustically coupled and fixed, and a part of the cable 2b or the plug of the headphone 2 is supported without applying tension to the cable 2b (S1). In this state, the headphone mounting part 1 and part of the cable 2b or the plug support part 4 are mechanically vibrated (S2).

  In the evaluation, an acoustic signal obtained from the microphone 3 is taken into the evaluation device 6 (S3), and processing is performed in consideration of auditory characteristics (A characteristics, B characteristics, C characteristics, loudness considering masking effects, etc.). S4) Thus, evaluation including psychological elements is performed.

  For example, a single noise exposure level may be used in the processing (S4) in consideration of the auditory characteristics.

  Here, the A characteristic is a human auditory characteristic, and the A characteristic sound pressure level corresponds to the noise level. The C characteristic is a correction characteristic for a loud sound, and the B characteristic is an intermediate characteristic between the A characteristic and the B characteristic. The masking effect sounds twice as loud when the two sounds are separated when the two pure tones are heard at the same volume, but it is not twice as loud when the sounds are close in frequency. It is a phenomenon that can be heard as a smaller sound.

  On the other hand, loudness is the volume of sound perceived by humans. If the frequency is different even at the same sound pressure level, the volume of the sound varies. In order to measure this loudness, “auditory frequency characteristics” and “auditory masking effect” are two important factors. In the case of noise including various frequencies, it does not coincide with the volume of sound felt by a person. Therefore, by evaluating the auditory characteristics such as loudness in consideration of the masking effect, it is possible to make an evaluation more suited to human hearing.

  In this way, it is possible to quantitatively evaluate mechanical noise that affects the feeling of use of the headphones. Moreover, an evaluation result close to the level of sound felt by a person can be obtained by performing processing in consideration of auditory characteristics on the acoustic signal. As a result, a measurement result closer to the feeling of use of the headphones can be obtained.

  Therefore, according to the present invention, it is possible to provide a measurement device and a measurement method for headphone mechanical noise that enables quantitative evaluation of mechanical noise that affects the feeling of use of the headphone.

  Although the present invention has been described with reference to the embodiments, the present invention is not limited to the above embodiments, and various modifications can be made without departing from the scope of the invention at the stage of implementation.

1 Headphone wearing part (fixing means)
2 Headphone 2a Ear chip 2b Cable 3 Microphone 4 Cable support (support means)
5 Excitation source (excitation means)
6 Evaluation device (Evaluation means)

Claims (7)

  With the headphones (2) attached, the fixing means (1) for acoustically coupling and fixing the headphones (2) and the microphone (3), and the cable (2b) of the headphones (2) without tension. A support means (4) for supporting a part of the cable (2b) or a plug, and a cable (2b) between the mounting means of the headphones (2) and the support means (4) in the fixing means (1) And an evaluation means for evaluating the acoustic signal measured by the microphone (2) when the vibration means (5) vibrates the cable (2b). 6) A device for measuring mechanical noise of headphones.   The headphone (2) mounting portion is made of an elastomer, and preferably has an elastic modulus of 1 MPa or less in an audible band having a frequency of 20 to 20 KHz. measuring device.   The apparatus for measuring mechanical noise of headphones according to claim 1 or 2, wherein the vibration means (5) has a mechanical impedance lower than that of a part of the headphone (2) to be vibrated.   The headphone (2) and the microphone (3) are acoustically coupled and fixed, and a part of the cable (2b) or the plug of the headphone (2) is supported without tensioning the cable (2b), Mechanically oscillating between the mounting part of the headphone (2) and a part of the cable (2b) or the support part (4) of the plug, and evaluating the acoustic signal measured by the microphone (2). A measurement method of mechanical noise of headphones characterized by the above.   5. The method of measuring mechanical noise of headphones according to claim 4, wherein the excitation source has less irregularities in the frequency characteristics of the excitation force including impulse, M series, chirp or white noise.   The obtained acoustic signal is processed in consideration of auditory characteristics including at least one of A characteristic, B characteristic, C characteristic, or loudness considering masking effect, and an evaluation result is obtained. A method for measuring mechanical noise of headphones according to claim 4 or 5. 7. The method of measuring mechanical noise of headphones according to claim 6, wherein the evaluation result has a high correlation with a psychological experiment result.

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