JP2010171745A - Hearing protection method and hearing protection system in organoleptic assessment of abnormal sound emitted from electroacoustic transduction apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hearing protection method and a hearing protection system in the organoleptic assessment of an abnormal sound emitted from an electroacoustic transduction apparatus that can lower sound pressure by reducing a fundamental wave component of a sound wave emitted from the electroacoustic transduction apparatus. <P>SOLUTION: Electric continuous vibrations are supplied to the specified electroacoustic transduction apparatus 13 to output a sound wave S, which is picked up by a sound pickup microphone 15 and outputted to be heard with headphones 20, wherein sound pressure applied to the ears of a listening worker is lowered by reducing the fundamental wave component thereof to facilitate the discrimination of the abnormal sound emitted from the electroacoustic transduction apparatus 13 itself. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention is intended to prevent a hearing worker from causing a significant burden on the ear and causing a decrease in hearing when a hearing worker performs a sensory test for the presence or absence of abnormal sounds generated by electroacoustic transducers such as headphones and speakers. The present invention relates to a hearing protection method and a hearing protection system during sensory inspection of abnormal sounds emitted from electroacoustic transducers.

  Individual electroacoustic transducers such as headphones and speakers may generate a specific abnormal sound due to a defect in the vibration unit. As a method for detecting this, for example, a detection method described in Non-Patent Document 1 below Has already been proposed.

Journal of the Acoustical Society of Japan, Vol. 47, No. 7 (1991), p.484

  According to the said nonpatent literature 1, it is supposed that the cause of generation | occurrence | production of a sound with a rattle exists in the nonlinear phenomenon which a diaphragm or a voice coil contacts a flame | frame, a yoke, a magnet, etc. by rolling of a voice coil.

  As for the signal processing method that automatically detects the occurrence of a sound with a chatter, a method is adopted in which a judgment is made based on the autocorrelation of the time envelope of the signal obtained by band-filtering the output sound. It has been proved that the presence or absence of billiness can be determined with extremely high accuracy when this method is applied.

  However, a device that realizes the technique disclosed in Non-Patent Document 1 is a complex and expensive product that is produced at a site that produces electroacoustic transducers such as headphones and speakers that are inexpensive units. From the viewpoint of cost reduction, there is a disadvantage that it cannot be easily introduced.

  For this reason, the individual inspection of abnormal sound of the electroacoustic transducer, which is such an inexpensive unit, does not rely on the sensory inspection by the ear of the listening worker under the condition that a large sound wave is generated to make it easy to hear. Therefore, there has been a demand for a simple hearing protection method for preventing hearing loss even when engaged in work for a long time.

  In view of the above-mentioned problems of the prior art, the present invention collects sound waves generated by individual electroacoustic transducers with a sound-collecting on-microphone, and reduces the sound pressure applied to the ear of the hearing worker by reducing the fundamental component. An object of the present invention is to provide a hearing protection method and a hearing protection system at the time of a sensory test for abnormal sounds generated by an electroacoustic transducer capable of performing sound.

  The present invention has been made to achieve the above object, and the first invention (method) of the invention is to apply an electrical continuous vibration to a specific electroacoustic transducer to output it as a sound wave, and to output the sound wave. Abnormal sound generated by the electroacoustic conversion device itself by reducing the sound pressure applied to the ear of the listening worker by reducing the fundamental component when the sound is picked up by the sound collecting microphone and output through the headphones is possible. The main feature is to facilitate the discrimination.

  The second invention (system) includes an oscillator that generates an electrical continuous vibration, a power amplifier that amplifies the continuous vibration from the oscillator, and the continuous vibration amplified through the power amplifier as sound waves. An electroacoustic transducer that outputs, a sound collecting microphone that picks up sound waves output from the electroacoustic transducer, a control amplifier that adjusts sound waves picked up by the sound collecting microphone, and an adjustment through the control amplifier A headphone for listening to the generated sound wave, and a fundamental circuit component is reduced by interposing a subtraction circuit between the headphone and the control amplifier, and a delay circuit between the subtraction circuit and the oscillator. Thus, the main feature is that the sound pressure applied to the ear of the listening worker is reduced.

  According to the present invention, when an electrical continuous vibration is applied to a specific electroacoustic transducer and output as a sound wave, the sound wave is collected by a sound collecting microphone, and the sound can be output through headphones. By reducing the wave component, the sound pressure applied to the ear of the hearing worker is reduced to facilitate the discrimination of abnormal sounds generated by the electroacoustic transducer itself, so that the hearing worker performs a sensory test over a long period of time. However, it is possible to prevent hearing loss.

The block diagram which shows the structural example of the 2nd invention (system) with which the 1st invention (method) is applied.

  FIG. 1 is a block diagram showing a configuration example of a second invention (system) to which the first invention (method) is applied. According to the figure, the whole is an oscillator 11 that generates an electric continuous vibration, a power amplifier 12 that amplifies the continuous vibration from the oscillator 11, and the continuous vibration that is amplified through the power amplifier 12. Is converted as a sound wave S, a sound collecting microphone 15 that picks up the sound wave S output from the electro sound converting device 13, and a sound wave signal collected by the sound collecting microphone 15 is adjusted. A control amplifier 16, a power amplifier 19 that amplifies the sound wave signal adjusted through the control amplifier 16, and a headphone 20 that converts the sound wave signal amplified through the power amplifier 19 into a sound wave so that the sound can be heard. Configured.

  Further, a subtracting circuit 18 is connected between the control amplifier 16 and the power amplifier 19, and a delay circuit 18 is interposed between the oscillator 11 and the subtracting circuit 18, respectively.

  In this case, the oscillator 11 is configured as an electronic circuit that generates a required electrical continuous waveform such as a sine wave under an active element such as a transistor or FET.

  The power amplifier 12 connected to the subsequent stage of the oscillator 11 is also called a main amplifier, and is arranged to supply a large current to the electroacoustic conversion device 13 having a low impedance of several Ω.

  The electroacoustic conversion device 13 as an inspection target connected to the output side of the power amplifier 12 includes a speaker 14 as shown in the figure, headphones (not shown), and the like, and generates itself upon receiving an input signal. A sound wave S including abnormal sound (billed sound) is output for a predetermined time.

  The sound collection microphone 15 arranged on the sound emission side of the electroacoustic conversion device 13 is arranged for collecting the sound wave S emitted from the electroacoustic conversion device 13 and converting it into a corresponding sound wave signal (electric signal). For example, an omnidirectional condenser microphone can be preferably used.

  The control amplifier 16 connected to the output side of the sound collection microphone 15 is also referred to as a preamplifier, and is arranged so that the sound wave signal output from the sound collection microphone 15 can be adjusted and output to the subsequent stage.

  A subtraction circuit 18 is disposed between the control amplifier 16 and the power amplifier 19. The subtracting circuit 18 is connected to the oscillator 11 via a delay circuit 17 that delays by the same time as the time interval of the sound wave S emitted from the electroacoustic transducer 13, and is connected to the input voltage from the control amplifier 16. An output proportional to the difference from the input voltage from the oscillator 11 is obtained.

  That is, the delay circuit 17 and the subtraction circuit 18 play a role of reducing the fundamental wave component by subtracting the signal that drives the electroacoustic conversion device 13 by delaying the signal by the same time.

  Thus, the output through the subtracting circuit 18 is input to the headphone 20 through the power amplifier 19 under a state in which the fundamental wave component is reduced, while reducing the sound pressure applied to the ear of the listening worker, It will be easy to hear the sound.

  Therefore, according to the present invention, the electrical continuous vibration generated by the oscillator 11 is applied to the specific electroacoustic transducer 13 and output as the sound wave S under the inexpensive system configuration, and the sound wave S is collected. When the sound is picked up by the microphone 15 and output from the headphone 20 is possible, the electroacoustic conversion device 13 itself reduces the sound pressure caused by the unpleasant sound applied to the ear of the listening worker by reducing the fundamental wave component. By facilitating the discrimination of abnormal sounds that occur, it is possible to prevent hearing impairment from occurring even if the listening worker performs a sensory test for a long time.

DESCRIPTION OF SYMBOLS 11 Oscillator 12 Power amplifier 13 Electroacoustic transducer 14 Speaker 15 Sound collection microphone 16 Control amplifier 17 Delay circuit 18 Subtraction circuit 19 Power amplifier 20 Headphone S Sound wave

Claims (2)

By applying an electrical continuous vibration to a specific electroacoustic transducer and outputting it as a sound wave, collecting the sound wave with a sound collecting microphone and outputting the sound through headphones, the fundamental wave component can be reduced. Hearing protection at the time of sensory inspection of abnormal sound generated by the electroacoustic transducer, characterized by reducing the sound pressure applied to the ear of the hearing worker and facilitating discrimination of the abnormal sound generated by the electroacoustic transducer itself Method. An oscillator that generates an electrical continuous vibration, a power amplifier that amplifies the continuous vibration from the oscillator, an electroacoustic transducer that outputs the continuous vibration amplified through the power amplifier as a sound wave, and the electroacoustic A sound collecting microphone that picks up sound waves output from the conversion device, a control amplifier that adjusts sound wave signals picked up by the sound collecting microphone, and a power amplifier that amplifies sound wave signals adjusted through the control amplifier, A headphone that converts the sound wave signal amplified through the power amplifier into a sound wave to enable listening,
A subtracting circuit is interposed between the control amplifier and the power amplifier, and a delay circuit is interposed between the subtracting circuit and the oscillator to reduce the fundamental wave component, thereby reducing the sound applied to the hearing worker's ear. Hearing protection system at the time of sensory inspection of abnormal sound emitted by an electroacoustic transducer characterized by lowering pressure.

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