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Effect of Reverberation on Spatial Unmasking for Nearby Speech Sources. Barbara Shinn-Cunningham, Lisa Mraz, and Norbert Kop ã o Hearing Research Center Boston University. Supported by AFOSR. Motivation. “Spatial unmasking” arises when target and masker are spatially separated
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Effect of Reverberationon Spatial Unmaskingfor Nearby Speech Sources Barbara Shinn-Cunningham, Lisa Mraz, and Norbert Kopão Hearing Research Center Boston University Supported by AFOSR
Motivation • “Spatial unmasking” arises when target and masker are spatially separated • changes in energy at the ear • changes in binaural cues • What is tradeoff of including reverberation? • should alter spatial unmasking
Previous Study(Shinn-Cunnningham, et. al., in press) • Nearby speech/masker sources • large interaural level difference • big differences in target/masker ratios at the two ears • Zurek model predicts many results, but not when large ILDs in masker
8 spatial configurations masker (M) target (T) Conditions • 3 listening conditions • binaural, left, right
anechoic Reverberant Head-Related Impulse Responses • 2 room conditions • anechoic • reverberant 1 0 . 8 0 . 6 0 . 4 0 . 2 Impulse Response Pressure 0 • reverberant - 0 . 2 - 0 . 4 - 0 . 6 - 0 . 8 - 1 4 6 8 1 0 1 2 1 4 1 6 1 8 2 0 T i m e ( m s )
Methods • T “clear speech” sentences (thanks to K. Payton) • M speech-shaped noise • Remove overall level effects at better ear • fix masker (M) level at better ear • adaptively vary target (T) level to 50% correct • Block by listening/room condition • Repeat 3 or more runs to get std. err. < 1 dB
Better-Ear Advantage Difference between monaural thresholds at better and worse ears
Better-Ear Advantage • Predict no significant difference • M = masker • T = target
Better-Ear Advantage • Predict ordinary head-shadow difference • M = masker • T = target
Better-Ear Advantage • Predict larger-than-normal difference • M = masker • T = target
Better-Ear Advantage • Predict very large difference • M = masker • T = target
Better-Ear Advantage Better Ear - Worse Ear Threshold (dB)
Better-Ear Advantage Better Ear - Worse Ear Threshold (dB)
Better-Ear Advantage Better Ear - Worse Ear Threshold (dB)
Better-Ear Advantage Better Ear - Worse Ear Threshold (dB)
Better-Ear AdvantageReverberant Conditions If anything, expect reduced better-ear advantage
Better-Ear Advantage Better Ear - Worse Ear Threshold (dB)
Binaural Advantage Difference between binaural and better ear thresholds
Binaural Advantage • Predict little binaural advantage • M = masker • T = target
Binaural Advantage • Predict binaural advantage • M = masker • T = target
Binaural Advantage • Predict samebinaural advantage • M = masker • T = target
Binaural Advantage Binaural - Better Ear Threshold (dB)
Binaural Advantage Binaural - Better Ear Threshold (dB)
Binaural Advantage Binaural - Better Ear Threshold (dB)
Binaural AdvantageReverberant Conditions If anything, expect reduced binaural gain
Binaural Advantage Binaural - Better Ear Threshold (dB)
Binaural Advantage Binaural - Better Ear Threshold (dB)
Conclusions • Better-ear advantage can be very large • Reverberation reduces the better-ear advantage • Binaural-processing advantage only present if • T and M in different directions • Masker ILD is not extraordinarily large • Reverberation reduces binaural gain