Hearing Protection and Speech Communication Characteristics of Selected USAF Inflight Helmets.
Abstract
Hearing protection and speech intelligibility were measured on three widely used flight helmets: the HGU-26/P with standard earcups, HGU-26/P with custom earcups and the DH-151. The following results were obtained: (1) Attenuation tests demonstrated the DH-151 and the standard HGU-26/P generally provide equivalent hearing protection with the former providing somewhat greater protection at the low and high frequencies, but the latter providing somewhat greater protection at the middle frequency region. The custom HGU-26/P provided less hearing protection than both of the above. (2) Replacing earcup assemblies with standard MX8376/AR earcups resulted in equal or improved hearing protection for the HGU-26/P helmet. In the DH-151 helmet, this resulted in less protection at the lower frequencies, but improved protection in the middle frequency range, and no change in the higher frequency range. (3) Speech intelligibility was determined by calculating the articulation index. Both the standard HGU-26/P and the DH-151 provide excellent speech intelligibility. The custom HGU-26/P was found to provide less speech intelligibility than the other two helmets. Never-the-less, we believe it would also permit adequate inflight speech communication. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 01, 1980
- Accession Number
- ADA088099
Entities
People
- Donald G. Tomerlin
- Mark R. Stephenson
Organizations
- Air Force Research Laboratory