What can active noise reduction headsets do for you?
Nixon-CW; McKinley-RL; Steuver-JW; McCavitt-AR
Proceedings: 1992 hearing conservation conference, April 1-4, 1992. Cincinnati, OH: U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, task order 91-37982, 1992 Apr; :107-110
The active noise reduction (ANR) performance of voice communication headsets used by the United States Air Force was evaluated. Data from laboratory investigations included total and passive sound attenuation of the headset units. Active cancellation was calculated as the difference between total and passive attenuation at each of the one third octave band test signals. Overall sound attenuation was measured for some headsets at selected sound pressure levels ranging from 120 to 135 decibels (dB). Personal communications with developers, users, and other investigators provided additional insight on performance and utility of ANR headsets in real world situations. Results showed that maximum active attenuation in four circumaural devices tested was 15 to 22dB, and that this occurred at 100 to 250 Hertz. Of three devices tested at very high pink noise levels, two continued to operate at the 135dB sound pressure level (SPL), but the amount of ANR was 0dB to 5dB. The third headset provided effective ANR at lower SPLs, but ceased to function above 130dB. Aircrew comments on flight test experience indicated active attenuation and clearly much less noise at the ears, as well as improved quality and clarity of speech due to a better signal to noise ratio. Speech intelligibility measured in the presence of pink noise showed improvements of 5% to 10%. The role of headsets in hearing conservation within military noise environments was discussed. The authors conclude that ANR headsets provide capabilities that permit personnel to safely remain in certain noise environments for longer periods, and improve voice communication, but do not provide any change of noise with a high frequency spectrum.
Audiometry; Ear-protectors; Hearing-disorders; Military-personnel; Noise-induced-hearing-loss; Speech-transmission; Noise-measurement; Noise-levels; Voice-communication
Proceedings: 1992 hearing conservation conference, April 1-4, 1992