Abstract:

When listeners are presented with lead and lag pairs of clicks from two loudspeakers in an anechoic room, they hear a single image near the location of the lead loudspeaker, provided that the delay of the lag is only a few ms. However, Thurlow and Parks [Perceptual and Motor Skills 13, 7--12 (1961)] reported that the addition of a continuous background of noise from a single loudspeaker causes the lag click to become audible as a separate auditory event. The current experiment investigated whether this apparent breakdown of echo suppression would also occur if the background noise was presented from two loudspeakers with one delayed relative to the other. The signal was a pair of brief white-noise bursts presented from loudspeakers located at 45 deg right and 45 deg left in an anechoic chamber, with delays ranging from 2 to 14 ms. A continuous background white noise presented from the same two loudspeakers disrupted echo suppression only when the direction of its time delay was inconsistent with the signal delay. One interpretation is that echo suppression was broken because stimulus and noise provided conflicting information about the acoustics of the room. [Work supported by NIH DC01625.]