Lateralization of pulsed sinusoids based on interaural onset, ongoing, and offset temporal differences.

When pulsed sinusoids are presented to the ears with an interaural temporal difference but with no rise–decay time or filtering, three values of interaural time are present: onset, ongoing, and offset interaural differences. Lateral discrimination based on interaural temporal differences was studied for such stimuli. The sinusoids were either equal‐energy or constant‐intensity 65 dB SPL tones. The frequencies of the tones ranged from 150 to 4050 Hz and the durations covered a range of 2 msec–1 sec. The threshold value of interaural time obtained in the lateral discrimination task increased as a function of increasing frequency when intensity was maintained constant. When equal‐energy signals were used, the change in lateralization as a function of changes in frequency depended on signal duration. All lateral discrimination thresholds were approximately the same when the onset and offset temporal differences were reduced or eliminated by applying a bandpass filter, high‐pass filter, or a rise–decay time, or by presenting the signals with only an ongoing temporal difference. Low‐pass filtering the 4050‐Hz signals produced lateral discriminations approximately equal to those obtained with no filtering. These results suggest that low‐frequency information is the crucial variable for lateralization sinusoidal stimuli presented with onset, ongoing, and offset interaural temporal differences.