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The current status of standards for testing electroacoustic hearing protectors.
Murphy WJ; Franks JR
First Pan-American/Iberian Meeting on Acoustics/144th Meeting of the Acoustical Society of America, Cancun, Mexico, Dec 2-6, 2002. Melville, NY: Acoustical Society of America, 2002 Dec; :1-15
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
National Institute for Occupational Safety and Health, Hearing Loss Prevention Section, 4676 Columbia Parkway, MS C-27, Cincinnati, OH 45226-1998
First Pan-American/Iberian Meeting on Acoustics/144th Meeting of the Acoustical Society of America, Cancun, Mexico
Page last reviewed: March 3, 2021
Content source: National Institute for Occupational Safety and Health Education and Information Division