The effect of carrier and modulation frequency on lateralization based on interaural phase and interaural group delay.

The sensitivity of Observers to interaural delay in either the envelope or the carrier of an amplitude-modulated sinusoid was measured in a two-interval forced-choice task as a function of the frequency of the modulation and the frequency of the carrier. The two types of delay were set in opposition with the carrier leading in one ear but the modulation leading in the other. Lateralization appeared to be based on carrier (phase) delay when carrier frequency was below 1500 Hz, whatever the modulation frequency. For carrier frequency greater than 1500 Hz, lateralization performance was dependent both on carrier and on modulation frequency and was based on modulation (group) delay.