Cross-Modulation Interference With Lateralization of Mixed-Modulated Waveforms PurposeThis study investigated the ability to use spatial information in mixed-modulated (MM) sounds containing concurrent frequency-modulated (FM) and amplitude-modulated (AM) sounds by exploring patterns of interference when different modulation types originated from different loci as may occur in a multisource acoustic field.MethodInteraural delay thresholds were measured from 5 normal-hearing adults ... Article
Article  |   December 01, 2010
Cross-Modulation Interference With Lateralization of Mixed-Modulated Waveforms
 
Author Affiliations & Notes
  • I-Hui Hsieh
    National Central University, Jhongli City, Taiwan
  • Agavni Petrosyan
    National Central University, Jhongli City, Taiwan
  • Óscar F. Gonçalves
    University of Minho, Braga, Portugal
  • Gregory Hickok
    University of California at Irvine
  • Kourosh Saberi
    University of California at Irvine
  • Contact author: Kourosh Saberi, Department of Cognitive Sciences, University of California, Irvine, Irvine, CA 92692. E-mail: saberi@uci.edu.
Article Information
Hearing & Speech Perception / Acoustics / Speech, Voice & Prosody / Hearing
Article   |   December 01, 2010
Cross-Modulation Interference With Lateralization of Mixed-Modulated Waveforms
Journal of Speech, Language, and Hearing Research, December 2010, Vol. 53, 1417-1428. doi:10.1044/1092-4388(2010/09-0206)
History: Received September 20, 2009 , Accepted March 29, 2010
 
Journal of Speech, Language, and Hearing Research, December 2010, Vol. 53, 1417-1428. doi:10.1044/1092-4388(2010/09-0206)
History: Received September 20, 2009; Accepted March 29, 2010
Web of Science® Times Cited: 2

PurposeThis study investigated the ability to use spatial information in mixed-modulated (MM) sounds containing concurrent frequency-modulated (FM) and amplitude-modulated (AM) sounds by exploring patterns of interference when different modulation types originated from different loci as may occur in a multisource acoustic field.

MethodInteraural delay thresholds were measured from 5 normal-hearing adults for an AM sound in the presence of interfering FM and vice versa as a function of interferer modulation rate. In addition, the effects of near versus remote interferer rates, and fixed versus randomized interferer interaural delay, were investigated.

ResultsAM interfered with lateralization of FM at all modulation rates. However, the FM interfered with AM lateralization only when the FM rate was higher than the AM rate. This rate asymmetry was surprising given the prevalence of low-frequency dominance in lateralization, but was predicted by a cross-correlation model of binaural interaction. Effects were similar for fixed and randomized interferer interaural delays.

ConclusionsThe results suggest that in multisource environments, sources containing different modulation types significantly interfere with localization in complex ways that reveal interactions between modulation type and rate. These findings contribute to the understanding of auditory object formation and localization.

Acknowledgments
This work was supported by Grant NSC 98-2410-H-008-081-MY3 from the National Science Council, Taiwan; Grant BCS0477984 from the National Science Foundation; and Grant R01DC009659 from the National Institutes of Health. We thank Bruce G. Berg and Virginia M. Richards for helpful comments.
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