In considering the sensitivity of the ear, we made use of a pair of curves by Sivian and White showing the minimum audible sound levels at different frequencies. These have been the standard “threshold” curves for much of auditory work for the decades since. It can hardly be claimed, however, that they represent a formal standard for normal pure-tone thresholds. They were taken on 9 people at the Bell Laboratories who presumably had normal hearing, but were selected mostly for convenience. The measurements were taken in an acoustic environment that is ideal for measuring absolute sensitivity, but not easy to duplicate—namely a well isolated, anechoic chamber. When we prepare to work with or to understand auditory systems that are not functioning normally different considerations apply in setting a baseline for normal hearing for pure tones.
KeywordsSound Pressure Level Pure Tone Bone Conduction Ossicular Chain American National Standard Institute
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