[Buildup of echo suppression for the high frequency signal]

The buildup of echo suppression for noise bursts in the band of 5-18 kHz was studied. Durations of the bursts were 5, 10, 20 and 100 ms. Test stimulus were preceded by a train of stimuli. The stimulus was a noise burst pair, in which the lead burst was presented from either the left (+45 deg) or right (-45 deg) side, and the lag burst was presented from the opposite side. The train consisted of 10 stimuli. The echo delays were 1, 2, 4, 8, 16, 32, 64 and 125ms. The echo threshold was measured as the minimum echo delay at which subjects reported hearing one sound rather than two sounds. The average echo thresholds were significantly elevated for all durations of bursts for buildup condition. However, despite the fact that the average threshold was slightly higher in case of the right-side lead signal presentation than that in case of its left-side presentation, there was no significant difference for the signals of 5, 10, 20, and 100 ms in duration (p > 0.05).