The role of interaural time difference and fundamental frequency difference in the identification of concurrent vowel pairs.

The ability of subjects to identify both components of a concurrent vowel pair was determined when vowel fundamental frequency difference and an interaural time difference (ITD) in one of the vowels were introduced. In agreement with earlier studies it was found that introduction of a fundamental frequency difference significantly improved detection performance (by 22% for a 1 semitone difference). Identification performance improved as the ITD was made larger but this improvement was small compared to the fundamental frequency difference effect (7% improvement between 0 and 400 ps).