Experienced Ss identified (2IFC) the signal complex that contained a gap. When the complexes were of the same frequency, gap detection remained constant over the durations employed (up to 300 msec). When duration of the signal was 10 msec no changes in gap threshold occurred over the range of frequency disparities between signals (up to 120 Hz at F0 = 1 kHz). However, as signal duration increased (beyond 10 msec) there was an increase in gap threshold with increased frequency disparity. The degradation in gap threshold was greater for longer-duration events. Gap threshold was shown to decrease as a function of increase in intensity of the signals.