The temporal acuity for processing interaural cues

Abstract

It was during a three month visit of the first author to his Lab in 1998 that Tino pointed out an elegant study on detecting changes in Interaural Cross Correlation of stimuli that were roved in baseline Interaural Time Delay and Interaural Level Difference (Bernstein and Trahiotis, J. Acoust. Soc. Am. 102, 1113). This study showed that, even though ICC can only change due to the presence of dynamically varying ITDs and ILDs, the ICC can be perceived as a separate cue in certain conditions. This articulate notion of three perceptually independent binaural cues, ITD and ILD, relating to perceived laterality, and ICC, related to perceived width, is applied in low bit-rate audio coding where these cues are used to encode the spatial image of stereo sound recordings. The entanglement of these cues on a signal basis raises the question of the time scale at which these three cues are perceptually evaluated. Some recent findings will be discussed that show that the ITD and ICC can be evaluated with a high temporal acuity of less than 10 (ms) in stimuli where these cues alternate periodically, and that these patterns of alternating binaural cues give rise to a modulation percept.