On Sound Localization

Abstract

The binaural cues for sound localization are effective only in determining the angle between a given direction of sound and the axis of the ears (lateral angle). Since there is localization in the median plane, a second factor should be found which determines the direction of sound in this dimension.Head movement during sound localization might yield such a factor. With head movement the lateral angle of the sound changes giving a sequence of lateral angles characterizing the direction of sound geometrically in both dimensions.That sound localization actually works on this principle is proved by experiments in which directions of sound are synthetically produced. The sequence of lateral angles which a certain elevated direction of sound would yield with a certain head movement was determined. While the observer performed this head movement a sound was shifted in the horizontal plane in a way to present the same sequence of lateral angles. The observer perceived the sound in the direction from which the presented sequence of lateral angles was derived instead of in the actually given shifting position.