Signal transfer through the hearing protectors with the regulation of damping in the presence of the impulse noise

Abstract

Hearing protectors with the regulation of damping are used ever so more frequently to protect the hearing of persons endangered with the presence of impulse noise. A clear advantage coming from the use of this type of hearing protectors, compared to other types, lies in the improvement of the perception of useful signals. However, in spite of such advantages it is during their use one can observe the effect of “blocking” of the sound transfer underneath the protectors (meaning the limitation of the signal transfer through the protectors), occurring directly after the appearance of the acoustic impulse. The article presents an analysis of the acoustic signal transfer underneath the hearing protectors with the regulation of damping in the situation of the acoustic impulse appearance. The analysis aimed at the definition of the time of the “blocking” of noise transfer underneath the protectors effect as well as the decrease of the acoustic pressure level resulting from the mentioned effect. Towards that goal a special work stand was prepared, consisting of impulse signal source, a set noise and an acoustic tester (artificial head). The research had shown the time of the “blocking” effect during the use of the protectors with the regulation of damping to be reaching 1.2 seconds and the decrease in the value of the mean acoustic pressure level, resulting from such effect, to be exceeding even 16 dB.