A new nonlinear earplug for use in high-level impulse noise environment
Armand L. Dancer, Pascal J. F. Hamery · The Journal of the Acoustical Society of America · 1998
A nonlinear earplug allows speech communication, detection and localization of acoustic sources, and prevents hearing hazard from high-peak pressure impulses. Improved physical characteristics of a nonlinear earplug are explained: nonlinear attenuation starting with relatively small level (110 dB peak) and improvement of nonlinear attenuation for high levels. Such an earplug is especially designed against weapon noises (up to 190 dB peak). The study is based on experimental approach. Moreover, a theoretical model has been developed to explain the experimental results and to optimize the acoustic nonlinear filter dimensions and configuration. The nonlinearity of such a filter is due to one (or several) little hole(s), the acoustic impedance of which is essentially a viscous resistive one and depends on the particulate velocity in its center.