Minimum auditory movement angle: Binaural localization of moving sound sources

Abstract

Subjects [human] were asked to discriminate whether a sound was emanating from a moving or stationary source. The minimum audible movement angle (MAMA) thus defined increased as the source velocity increased. MAMA ranged from a low of 8.3.degree. with the slowest velocity employed (90.degree./s) to a high of 21.2.degree. with the fastest velocity (360.degree./s). In the 2nd experiment, subjects were asked to localize where the moving source was, at signal on and offset. The apparent onset was displaced in the direction of motion, and the amount of this displacement was directly related to source velocity. Less consistent results were observed with signal offset. The binaural system may be relatively insensitive to motion.