Current status of standards for testing electroacoustic hearing protectors.
J Acoust Soc Am 2002 Nov; 112(5)(Part 2):2317
Electroacoustic hearing protectors encompass several classes of electronics: level-limiting, amplitude compression and active noise control (ANC) devices. Each class of protector seeks to enhance performance by overcoming insertion loss and/or improving low-frequency attenuation. Level-limiting devices turn off the amplification when the external sound level exceeds a preset threshold. Amplitude compression devices apply variable gain and limit amplification of signals above the threshold. ANC devices create an out-of-phase signal under the protector to improve the low-frequency attenuation of earmuffs. ANC devices typically perform best in continuous noise that has strong harmonic components that can be predicted and cancelled. The different methods of enhancing protector performance require separate standards to understand both the static and dynamic performance. Testing of ANC devices has further requirements which require knowledge of both passive and active electronic conditions and in noise with different crest factors. This talk will review a variety of tests of the different protector classes.
Hearing-level; Hearing-protection; Hearing-threshold; Ear-protection; Ear-protectors; Noise-absorption; Noise-control; Electronic-components; Electronic-devices; Sound-attenuation; Testing-equipment
William J. Murphy, NIOSH Hearing Loss Prevention Section, 4676 Columbia Pkwy., M.S. C-27, Cincinnati, OH 45226-1998
Journal of the Acoustical Society of America