Abstract
A measure of the sound field at the base of the concha, obtained by using a miniature microphone located within the ear, provides information on the acoustical signal entering the ear canal. When combined with a portable tape recorder, the apparatus can be used to evaluate an individual's exposure to noise and appears to be particularly suited for use in directional sound fields that vary in the vicinity of the head. In order to compare the data obtained with existing criteria for hearing conservation, or sound level meter measurements in a diffuse field, a transfer function is used to produce the equivalent diffuse field that would exist at the center of the head in the absence of the subject. The device has been used to measure the noise levels experienced by operators of snowmobiles and chain saws as a function of time, and the attenuation and, in some cases, amplification of sound produced by some common forms of crash helmet and headgear. An over-all accuracy of ±2 dB is obtained from 100 to 5000 Hz by using a spectrum shaper and a built-in calibration system.
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call