The influence of pause, attack, and decay duration of the ongoing envelope on the extent of lateralization produced by interaural time differences of high-frequency stimuli

Abstract

Klein-Hennig et al. [J. Acoust. Soc. Am. 129, 3856 (2011)] investigated the influence of the duration of specific modulation cycle segments within the ongoing envelope waveform on the sensitivity to interaural time differences (ITD). The ITD sensitivity, measured in a two alternative forced choice discrimination task, was reported to increase for increasing pause and decreasing attack segment duration. The study also revealed that “on” and decay durations have little to no influence on the threshold ITD. The current study employed a subset of nine envelope shapes from the previous study and measured the extent of lateralization produced by ongoing ITDs with an acoustic pointing task. Lateralization generally increased monotonically with ITD for the measured values of 0.2, 0.6, 1, and 2 ms. An additional condition measured combined lateralization of a 1 ms ITD and an opposing 5 dB interaural level difference. It was observed that the extent of lateralization increases with increasing pause duration or with decreasing attack duration in line with the threshold ITD data. However, the different influence of attack and decay flank on ITD sensitivity translates into significant differences in the extent of lateralization only for a subgroup of subjects.