Helmet Electronics & Display System-Upgradeable Protection (HEaDS-UP) Phase III Assessment: Headgear Effects on Auditory Perception

Report No. ARL-TR-6723
Authors: Angelique A. Scharine; Rachel A. Weatherless
Date/Pages: November 2013; 56 pages
Abstract: Two prototype modular helmet systems were evaluated for their effects on auditory perception. The systems consist of a helmet, eye and mandible protection, and a tactical communications and protection system (TCAPS) that incorporates earmuffs (EM), earplugs (EP), or both. Minor differences in passive directional attenuation were measured for the two systems. The output levels of the situation awareness (SA) microphones of the TCAPS were measured as a function of noise level and amplification setting. It was shown that they limited noise transmission when ambient levels exceeded 85 decibels A-weighted (dB A); however, it was possible to amplify levels at 85 dB A by 20 decibels (dB). The attenuation of 145- and 160-dB peak impulses was measured for the EP and EM with the SA microphones off and when turned on. When the SA microphones were on, the TCAPS provided impulse noise protection equivalent to that of passive protection. When the helmets were worn without mandibles, auditory localization ability was similar to that observed for the Advanced Combat Helmet (ACH). Wearing the mandible caused significant decreases in localization ability. Listeners wearing the TCAPS system showed no impairment of recognition for speech presented in quiet as compared to unaided listening.
Distribution: Approved for public release
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Last Update / Reviewed: November 1, 2013