Breakdown of echo suppression with multiple echoes

If a sound is followed a few milliseconds later by its echo, the echo is often suppressed. If a train of repeating sources and echoes is established and then the source and echo are reversed, there is a temporary breakdown of echo suppression. A procedure has been developed for studying echo suppression in which listeners attend to the last sounds in a series of repeating sounds. Using this procedure the effect of multiple echoes (up to seven) on echo suppression and the breakdown of echo suppression was investigated. In all cases there is a breakdown in echo suppression when the echoes are changed in a number of ways. The results indicate an interaction among number of echoes, spatial location of the echoes, and the timing among the echoes in both echo suppression and its breakdown. The results will be discussed in terms of the concept that echo suppression depends on the listener’s prior experience in the acoustic environment. [Work supported by NIDCD and AFOSR.]