[Development of a computerized sound attenuation measurement system of hearing protectors based on Japanese...

Sound attenuation measurement of hearing protectors is done in accordance with JIS T 8161 in Japan. In the JIS T 8161 it is stated that more than three non-coherent sets which include a noise generator, one-third octave band-pass filter, amplifier, calibrated attenuator and signal interrupter are required. To realize this measurement system, various expenses and a large space are required. In our study, four channel test signals were generated by our programs, and fed to a digital/analog converter. Consequently, the hardware of a noise generator and one-third octave band-pass filter could be reduced. Moreover, a program, which automatically controlled sound pressure level by digitally controlled attenuators, was developed with the result that the sound attenuation measurement could be performed by operating the mouse. Furthermore, sound attenuation of the earplug was measured in accordance with JIS T 8161 to evaluate our system. The result showed that practical sound attenuation values were obtained by easy operation. It was considered that this system was effective in hardware reduction, and useful for sound attenuation measurement of hearing protectors.