Perception of interaural time differences at threshold and suprathreshold levels

Experiments were performed to study and compare the perception of interaural time dierences (ITDs) at threshold and suprathreshold levels. In a rst experiment, ITD thresholds were measured for 1-ERB-wide stimuli centered at frequencies between 150 and 1500 Hz. The interaural correlation was systematically varied between 1 and 0.85. For fully correlated signals, the dependence of the thresholds on the center frequency was in line with previous results, showing the highest ITD sensitivity between 750 and 1000 Hz. Thresholds measured for partially correlated stimuli were elevated but showed a similar dependence on frequency as the thresholds measured for fully correlated stimuli. In a second experiment, the task of the listeners was to align a broadband pointer signal carrying a single ITD, on a broadband target signal that carried a dierent ITD in each frequency band. The ITDs in the target signals were either close to threshold or at suprathreshold levels. The results showed that, in contrast to the dominance region between 750 and 1000 Hz observed in the case of close-to-thresholds presentation, ITD information is equally integrated across frequency for suprathreshold values.