The role of timbre in the segregation of simultaneous voices with intersecting F 0 contours

Abstract

When the fundamental frequency (F 0) contours of two speakers' voices intersect, the listener is presented with a problem. The listener must decide which of the F 0 contours emerging from the intersection is a continuation of which contour entering the intersection: have the F 0 contours crossed or merely approached and parted? In the present experiment, subjects listened to two simultaneous diphthong-like sounds with F 0 contours that either approached and diverged or crossed over. The task was to report whether the pitches "crossed" or "bounced" away from each other. Despite the changing timbres of the two sounds, the subjects were able to discriminate crossing and bouncing F 0s, provided that the timbres of the vowels differed at the moment when their F 0s were the same. When the timbres were the same, the subjects could not make the discrimination and tended to hear a bouncing percept. These results are consistent with the idea that listeners use continuity of timbre rather than continuity of F 0 movement to disambiguate F 0 intersections. © 1993 Psychonomic Society, Inc.