Auditory and Acoustical Evaluation of Several Shoulder-Rifles

摘要

The threshold of audibility of each ear of 178 soldiers was measured before and after firing various types of shoulder rifles at the rate of one trigger pull every five seconds. The acoustical impulses from each type of weapon were evaluated (peak pressure, time history, and spectrum). The peak pressures of the acoustic impulse from firing the weapons were highly correlated with threshold shifts caused by exposure to the gun noise. From these and related data, estimates are made of the expected permanent hearing level in the frequency region from 1000 cps to 6000 cps to be equalled or exceeded in 50, 25, and 10 percent of ears repeatedly exposed to gun noise at various peak sound-pressure levels. (Author)