1. 3-D Sound and Spatial Audio MUS_TECH 348

2. Stereo Loudspeaker Reproduction

3. Intensity Stereo Side Image

4. Intensity Stereo Center Image

5. Typical Pop/Rock and Classical Spatial Distribution

6. Off-Center Listening

7. “Precedence Effect”

8. Mono Compatibility

9. Why can’t we just reproduce binaural recordings over loudspeakers?

10. Binaural Recording with Loudspeaker Reproduction

11. Stereo Loudspeaker Reproduction Creates Notch at 2kHz

12. How to Eliminate Crosstalk? 1) Use a baffle

13. 2) Use out-of-phase signals

14. 180° Out of Phase Signals

15. 180° Out of Phase Loudspeakers

16. Alternatively

17. How to make Loudspeaker Reproduction Transparent?

18. 3) Crosstalk Cancellation from Manfred Schroeder (late 1950s) Exact Solution Make loudspeaker listening more like headphones All sounds externalized

19. Schroeder’s Cross-talk Cancellation System

21. One Step at a Time: Equalization of Loudspeaker Response EQ Filter Result

22. But…

23. Introduce cross-talk cancellation signal:

25. But… There is crosstalk for the crosstalk cancellation signal!

26. Full Cross-talk Cancellation Solution:

27. “Sweet Spot”

28. The Problems? 1.Off-center positions. Only one sweet spot. 2.Individual Differences. Listener’s HRTFs, including H 30 and H 330, don’t match. 3.High frequency cancellation. Wave lengths are so short that very slight shifts in position throw everything off. 4.1/H 30. Inverting the notches creates big peaks that probably don’t match the listener. 5.Room Acoustics. Indirection sound reaches the listener.

29. Off-Center Seating in Larger Spaces Good Each seating position has unique time of arrival delay and level differences. Only the center seats can provide spatial imagery.

30. Off-Center Seating in Larger Spaces The separation of the stereo loudspeakers creates different ranges of differences for time of arrival delay.

31. Off-Center Seating in Larger Spaces Delayed signal from loudspeaker can create a wide range of subjective impressions!

32. Off-Center Seating in Larger Spaces The range of time of arrival delays for typical loudspeaker separatations puts the delay in the range of these different subjective impressions

33. Loudspeaker Reproduction in Natural Environments Loudspeakers themselves create indirect sound.

34. Frequency and Time Response of Loudspeaker in an Empty Room Impulse response and amplitude response from the loudspeaker to the listener in an empty test room.

35. Figure 2 shows change with a few absorption panels in place.

36. More,

37. Figure 6 finally shows a rooms with only slight indirect sound between the loudspeaker and the listener.

38. Figure 6 impulse response and amplitude response.