Localization of amplitude-modulated high-frequency noise

This study investigated whether listeners can use interaural time differenc es (ITDs) in the amplitude envelope to localize high-frequency sounds in a free field. Localization accuracy was measured for high-frequency (7 to 14 kHz) noise with and without an imposed amplitude modulation (AM) at 20, 80 or 320 Hz. Only AM at 320 Hz led to more accurate localization relative to the nonmodulated condition. The results of a control experiment suggest tha t the improvement in localization accuracy was due to an increase in stimul us bandwidth, rather than the temporal cues provided by the modulation. (C) 2000 Acoustical Society of America. [S0001-4966(00)03306-3].