LATERALIZATION OF COMODULATED COMPLEX WAVE-FORMS

This study examines the ability to lateralize a complex signal charact erized by correlated temporal activity across widely separated frequen cy regions. The high-frequency complex consisted of two narrow-band st imuli. The two stimuli had common interaural delays but different carr iers centered on nonoverlapping critical bands. Two basic conditions w ere examined: The narrow-band stimuli had temporal envelopes which wer e (1) identical or (2) different. In the first experiment, narrow band s of noise were used which either Had identical temporal envelopes (co modulated) or statistically independent envelopes (CFs=2550 and 3350 H z). In the second experiment, two sinusoidally amplitude-modulated (SA M) tones were used whose modulators either had the same starting phase or a different starting phase (CFs=2550 and 4000 Hz). Results of the first experiment showed that for bandwidths narrower than 300 Hz, como dulated bands produced significantly lower interaural-delay thresholds compared to independent bands. Results of the second experiment showe d that when the two SAM tones (100-Hz modulation rate) had the same mo dulator starting phase, interaural-delay thresholds were lowest. (C) 1 995 Acoustical Society of America.