Perception of a secondary auditory image with three sound sources

In a three-sourer sound system, one of which is undelayed and the other two delayed, a listener facing these sources perceives an unexpected secondary auditory image in addition to the expected primary auditory image. The two delayed sources have time delays relative to the undelayed source within t he range in which the precedence effect operates. The secondary auditory im age is believed to be due to summing localization taking place between the two sound sources which have been delayed, when the relative time delay bet ween them is within the range for summing localization to occur.