1. Acoustical Society of America, Chicago 7 June 2001 Effect of Reverberation on Spatial Unmasking for Nearby Speech Sources Barbara Shinn-Cunningham, Lisa Mraz, and Norbert Kopão Hearing Research Center Boston University Supported by AFOSR

2. Acoustical Society of America, Chicago 7 June 2001 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

3. Acoustical Society of America, Chicago 7 June 2001 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

4. Acoustical Society of America, Chicago 7 June 2001 Conditions 3 listening conditions binaural, left, right 8 spatial configurations masker (M) target (T)

5. Acoustical Society of America, Chicago 7 June 2001 Reverberant Head-Related Impulse Responses 468101214161820 -1 -0.8 -0.6 -0.4 -0.2 0 0.2 0.4 0.6 0.8 1 Time (ms) Impulse Response Pressure anechoic reverberant 2 room conditions anechoic reverberant

6. Acoustical Society of America, Chicago 7 June 2001 T “clear speech” sentences (thanks to K. Payton) M speech-shaped noise Methods 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

7. Acoustical Society of America, Chicago 7 June 2001 Speech: T @ (0˚, 15 cm)

8. Acoustical Society of America, Chicago 7 June 2001 Better-Ear Advantage Difference between monaural thresholds at better and worse ears

9. Acoustical Society of America, Chicago 7 June 2001 Better-Ear Advantage Predict no significant difference M = masker T = target

10. Acoustical Society of America, Chicago 7 June 2001 Better-Ear Advantage Predict ordinary head-shadow difference M = masker T = target

11. Acoustical Society of America, Chicago 7 June 2001 Better-Ear Advantage Predict larger-than-normal difference M = masker T = target

12. Acoustical Society of America, Chicago 7 June 2001 Better-Ear Advantage Predict very large difference M = masker T = target

13. Acoustical Society of America, Chicago 7 June 2001 Better-Ear Advantage Better Ear - Worse Ear Threshold (dB)

14. Acoustical Society of America, Chicago 7 June 2001 Better-Ear Advantage Better Ear - Worse Ear Threshold (dB)

15. Acoustical Society of America, Chicago 7 June 2001 Better-Ear Advantage Better Ear - Worse Ear Threshold (dB)

16. Acoustical Society of America, Chicago 7 June 2001 Better-Ear Advantage Better Ear - Worse Ear Threshold (dB)

17. Acoustical Society of America, Chicago 7 June 2001 Better-Ear Advantage Reverberant Conditions If anything, expect reduced better-ear advantage

18. Acoustical Society of America, Chicago 7 June 2001 Better-Ear Advantage Better Ear - Worse Ear Threshold (dB)

19. Acoustical Society of America, Chicago 7 June 2001 Binaural Advantage Difference between binaural and better ear thresholds

20. Acoustical Society of America, Chicago 7 June 2001 Binaural Advantage Predict little binaural advantage M = masker T = target

21. Acoustical Society of America, Chicago 7 June 2001 Binaural Advantage Predict binaural advantage M = masker T = target

22. Acoustical Society of America, Chicago 7 June 2001 Binaural Advantage Predict same binaural advantage M = masker T = target

23. Acoustical Society of America, Chicago 7 June 2001 Binaural Advantage Binaural - Better Ear Threshold (dB)

24. Acoustical Society of America, Chicago 7 June 2001 Binaural Advantage Binaural - Better Ear Threshold (dB)

25. Acoustical Society of America, Chicago 7 June 2001 Binaural Advantage Binaural - Better Ear Threshold (dB)

26. Acoustical Society of America, Chicago 7 June 2001 Binaural Advantage Reverberant Conditions If anything, expect reduced binaural gain

27. Acoustical Society of America, Chicago 7 June 2001 Binaural Advantage Binaural - Better Ear Threshold (dB)

28. Acoustical Society of America, Chicago 7 June 2001 Binaural Advantage Binaural - Better Ear Threshold (dB)

29. Acoustical Society of America, Chicago 7 June 2001 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

30. Acoustical Society of America, Chicago 7 June 2001