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Abstract:
This report summarizes the results of the research performed at Boston University (and in collaboration with researchers at the Air Force Research Laboratory Hurnan Effectiveness Branch) on the acoustics and psychoacoustics of sound localization for sound sources near a listener's head, particularly in rooms where the effects of reverberation influence performance. The results of this work are unique in that little previous work has examined how the acoustics of the signals reaching a listener depend on the environment. Detailed analysis of the acoustic signals reaching a listener in a classroom demonstrate that the listener location relative to nearby walls has a dramatic impact on spatial acoustic cues. Source location relative to the listener also has a large impact; distortion of spatial cues generally grows with source distance and with source laterality. The ability to detect and understanding a sound source in the presence of a masker sound source improves when the competing sources are in different source locations. Results studying the effects of this "spatial unmasking" for nearby sources shows that the large interaural level differences that arise for nearby sources have an important influence on spatial unmasking. Furthermore, the influence of spatial unmasking decreases with growing levels of reverberant energy if the masker is a steady- state signal. However, the unmasking is robust in cases where the masking source is speech. The results suggest that even noisy, distorted spatial cues are sufficient to mediate competition between competing sources that are spectro- temporally complex, conditions in which "informational masking" dominates behavior.
| Limitations: |
 APPROVED FOR PUBLIC RELEASE |
| Description: |
Final rept. 1 Dec 2000-14 Jan 2004 |
| Pages: |
11 |
| Report Date: |
20 APR 2004 |
| Contract Number: |
F49620-01-1-0005 |
| Report Number: |
A872224 |
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Keywords relating to this report:
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