Comfortable Listening Levels for Pure Tones in Quiet and Noise

Abstract

The most comfortable listening level and the range of comfortable listening levels for pure tones were determined for a group of normal (nonclinical) listeners in the quiet and against various levels of background noise. In general, the most comfortable listening (mcl) level contour has the general shape of the equal-loudness contour at intermediate loudness levels—lowest intensity at the middle frequencies and highest intensity at the lower frequencies. The range of listening levels considered “comfortable” against a quiet background varies from about 20 db at the lowest frequencies to about 35 db at the middle frequencies. The variability of the mcl is larger at high frequencies than at low frequencies, and it is about the same magnitude as the variability of heterophonic equal-loudness matches. The effect of noise is primarily to raise the lower limit of the range of comfortable listening levels and only secondarily to raise the upper limit. As a result, the range of comfortable listening levels is decreased in noise. The possible use of the comfortable listening level test as a gross diagnostic tool in the detection of nerve-type deafness is discussed.