3aNS12. Low-frequency improvement for hearing protection devices.

Session: Wednesday Morning, December 4

Time: 11:30

Author: Jorge P. Arenas
Location: Inst. of Acoust., Univ. Austral de Chile, P.O. Box 567, Valdivia, Chile
Author: Juan A. Munita
Location: Microlab, Univ. Austral de Chile, Valdivia, Chile
Author: Ana M. Monsalve
Location: Herthastrasse 1m, 14193, Berlin, Germany
Author: Ana M. Salazar
Location: Asociacion Chilena de Seguridad, Santiago, Chile


The use of hearing protection devices has become a common measure of noise control in working environments. An efficient device must shield the receiver against the sound energy radiated from the noise sources in a wide range of frequencies. If the hearing protection made available is not potentially effective in preventing on-the-job excessive exposures, then the hearing conservation program will not achieve its goal of adequately protecting the noise exposed population. However, the commonly used hearing protection devices do not have a significant effect on low-frequency noise. The objective of this work is to develop an electronic device following the concepts showed by Conover's design based on superposition. The sound is decomposed by filtering, processing, and inverting in the ear channel. It must be noted that low-cost electronic components were used, allowing it to be incorporated in hearing protectors which had already been made. Improvement of insertion loss is calculated by means of standardized procedures in order to estimate practical applications, reduction in dB(A), and transfer functions in frequency domain. The performance of conventional hearing protectors used in industrial-noise control can be improved in some cases (low frequency), producing a significant increase in IL. [Work supported by ACHS.]

ASA 132nd meeting - Hawaii, December 1996