A BEHAVIORAL STUDY OF THE SOUND-SHADOW EFFECT IN IMPULSE NOISE.
Abstract
The sound-shadow effect of the human head in an impulse-noise field was studied by exposing 27 subjects to gunfire noise so their left ears were normal to the oncoming shock wave (near ear) and their right ears were protected by the shadow of the head (far ear). Noise exposure was continued until the subject's near ear demonstrated 15 dB temporary threshold shift (TTS) and the post-exposure TTS in near and far ears was compared. Peak pressure level at the entrance of the far ear canal was less than one-half that found at the near ear (153 vs. 161 dB re 0.0002 microbar). Mean TTS was significantly smaller in the far ears than it was in the near ears. The mean 'protection' afforded the far ear by the head's shadow ranged from three dB at 1 kHz to 12 dB at 6 kHz. The implications of the findings for the protection of weapon crewmen are discussed. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Jul 01, 1967
- Accession Number
- AD0659331
Entities
People
- David C. Hodge
- R. Bruce Mccommons
Organizations
- Human Engineering Laboratory