Investigating Hearing Loss Effects of Small Arms Fire


A human surrogate was developed to emulate the acoustic transmission path of a human ear. The physical model was used to study solider exposure to impulsive small weapons fire. The ear response of the surrogate and human data were in very good areement. The effect of the helmet and body armor equipment on a soldier's hearing was determined in this project through laboratory and firing range measurements. A sound pressure level (SPL) reduction of 2 to 3 dB on both left and right inner ears of the surrogate was found when a helmet was worn. This reduction was probably due to the helmet blocking the direct acoustic path from the weapon muzzle to the ear. Body armor appears to have very little effect on the sound reaching the inner ear. This implies taht reflections from the torso are a second order effect when compared to the direct acoustic path. The physics of the direct acoustic path from the weapon muzzle to the ears appears to be the most important acoustic mechanism affecting the innear ear SPL levels.

Key Publications

[pdf] P. C. Herdic, J. McMahon, B. R. Dzikowicz, B. H. Houston, and G. K. Hubler. Nrl technical year end progress report for mcsc pm-ice fy11 sow tasks 1 and 2 - hearing loss research. Technical Report MCSC PM-ICE, The Naval Research Laboratory, Washington, DC, 2012. [ bib ]