Lateralization on the basis of interaural envelope delays: The effect of component starting phase

Threshold interaural envelope delays were measured with a 2 AFC paradigm as a function of modulation frequency (fm = 25, 50, 100, 200, 300, 400, and 500 Hz) for three‐ and five‐component complexes whose center frequencies (fc) were equal to 4000 Hz. Comparisons were made between thresholds obtained when the starting phases were randomized and when they were all set to zero. The level of each component was approximately 50 dB SPL, and the signal duration was 200 ms with 10‐ms linear rise/decay times. While reductions in depth of modulation elevate threshold envelope delays [G. B. Henning, J. Acoust. Soc. Am. 55, 84–90 (1974)], no such effects were found for phase randomization even when modulation rates were low and all components fell within a critical band. This seems surprising in light of the fact that both reduce depth of modulation and phase randomization reduce the peak factors of the waveforms, which is commonly believed to interfere with entrainment by the peripheral auditory system. Efforts to re...