Abstract
Minimum audible angles (m.a.a.s) of untrained subjects were measured in a room using pure tone (0.5 to 8 kHz) and click train (noise) stimuli (two alternative, forcedchoice, constant stimulus with feedback and head movements permitted, horizontal plane, 0° azimuth). The m.a.a.s and standard deviations (SD) were 3.0°±5.2° for click trains and 10.9°±21.0° for pure tones. The m.a.a.s did not vary significantly with frequency. The m.a.a.s and their SDs matched values reported from localization error studies. Narrowing the testing range from 32° to 8° resulted in random responses to the pure tones, though the click trains were readily localized. One subject presented with 2500 trials using an 8 kHz pure tone (with feedback, 16° range) increased her responses from random to 88% correct during the testing. The click train m.a.a.s probably reflect the typical noise localizational abilities of the general population. For pure-tone m.a.a.s, experience/training may result in improved accuracy not applicable to the general public. The presence of a well defined time clue and a broad bandwidth sound results in significantly lower m.a.a.s than were obtained using pure tones which presumably present only interaural phase or intensity clues.
