Binaural Loudness Matching with Repeated Short Tones

Abstract

Six experienced and 20 naive observers were tested to determine the effect of tone duration and repetition rate on the normal observer's ability to make a binaural loudness match. Durations from 1 to 200 milliseconds, and repetition rates from 1 to 100/second were used with various frequencies and intensities. The results show that binaural loudness matching is slightly more accurate with low repetition rates, and with either very short, or fairly long, durations. The differences are, however, small compared to the magnitude of the errors (as measured by the standard deviation), and any repeated tone is more accurately matched than a steady tone. Of considerable interest is the fact that differences between subjects in the matching are much greater than differences within subjects. These differences are so large that there is some doubt that intensity per se can operate as a cue for the localization of a sound source. If intensity is used as a cue, then the observers must have learned to compensate for an inherent difference in the loudness of tones in the two ears, since, in many cases, the difference in the match of two observers is greater than the maximum possible difference in intensity between the two ears with a single sound source.