Doppler compensation in coaxial and offset speakers

1. An audio processor, comprising:

an audio crossover to separate a first frequency band from a second frequency band, the first frequency band having a lower frequency band than the second frequency band;

an excursion estimator to estimate from information of the first frequency band a predicted excursion of a low-frequency driver;

an interpolator to interpolate an adjustment to the second frequency band to compensate for the estimated excursion; and

circuitry to drive the adjusted second frequency band to a receiver.

2. The audio processor of claim 1 , wherein the receiver is a high-frequency driver.

3. The audio processor of claim 2 , further comprising circuitry to drive the first frequency band to the low-frequency driver.

4. The audio processor of claim 3 , wherein the interpolator comprises logic to compute a Doppler compensation for reflection of audio waveforms from the high-frequency driver off of the low-frequency driver.

5. The audio processor of claim 1 , wherein the interpolator comprises a mathematical model of a loudspeaker system containing the audio processor.

6. The audio processor of claim 5 , wherein the model of the loudspeaker system comprises a concentric speaker system, wherein a high-frequency driver is concentric with the low-frequency driver.

7. The audio processor of claim 6 , wherein the interpolator is configured to compute an audio waveform to cancel high-frequency waveforms reflected off of the low-frequency driver.

8. The audio processor of claim 5 , wherein the model of the loudspeaker system comprises an offset speaker system, wherein a high-frequency driver is offset from the low-frequency driver.

9. The audio processor of claim 8 , wherein the interpolator is configured to compute an audio waveform to cancel high-frequency waveforms reflected off of the low-frequency driver.

10. The audio processor of claim 1 , further comprising a linearization subsystem.

11. The audio processor of claim 10 , wherein the linearization subsystem comprises a loudspeaker model in a feedback loop with a non-linear compensator.

12. The audio processor of claim 1 , further comprising circuitry to drive the first frequency band to the low-frequency driver unmodified.

13. An integrated circuit comprising the audio processor of claim 1 .

14. A system-on-a-chip comprising the audio processor of claim 1 .

15. A discrete electronic circuit comprising the audio processor of claim 1 .

16. A loudspeaker system, comprising:

a woofer;

a tweeter; and

an audio processing circuit configured to:

separate a low-frequency band from a high-frequency band;

estimate from the low-frequency band an expected excursion of the woofer in response to the low-frequency band;

compute an adjustment to the high-frequency band to compensate for reflection of a high-frequency audio signal from the tweeter off of the woofer moving at the estimated excursion;

drive the low-frequency band to the woofer; and

drive the adjusted high-frequency band to the tweeter.

17. The loudspeaker system of claim 16 , wherein the audio processing circuit is configured to drive the low-frequency band to the woofer unadjusted.

18. The loudspeaker system of claim 16 , wherein the audio processing circuit is further configured to compute a Doppler compensation for reflection of audio waveforms from the tweeter off of the woofer.

19. A method of performing audio processing for a loudspeaker system, comprising:

separating a first frequency band from a second frequency band, the first frequency band having a lower frequency band than the second frequency band;

estimating from the first frequency band a predicted excursion of a low-frequency driver;

interpolating an adjustment to the second frequency band to compensate for the predicted excursion; and

driving the adjusted second frequency band to a high-frequency driver.

20. The method of claim 19 , wherein interpolating comprises computing a Doppler compensation for reflection of audio waveforms from the high-frequency driver off of the low-frequency driver.

21. The method of claim 19 , further comprising:

driving the first frequency band to the low-frequency driver.

22. The method of claim 21 , further comprising:

computing an audio waveform to cancel high-frequency waveforms reflected off of the low- frequency driver.

23. The method of claim 21 , further comprising:

driving the first frequency band to the low-frequency driver unmodified.

24. One or more non-transitory computer-readable media having instructions stored thereon, wherein the instructions, when executed by a system, cause the system to:

separate a first frequency band from a second frequency band, the first frequency band having a lower frequency band than the second frequency band;

estimate, based at least on information of the first frequency band, a predicted excursion of a low-frequency driver;

interpolate an adjustment to the second frequency band to compensate for the estimated excursion; and

drive the adjusted second frequency band to a receiver.

25. The one or more non-transitory computer-readable media according to claim 24 , wherein the instructions, when executed by a system, cause the system to:

drive the first frequency band to the low-frequency driver.

26. The one or more non-transitory computer-readable media according to claim 24 , wherein the instructions, when executed by a system, cause the system to:

compute a Doppler compensation for reflection of audio waveforms from the receiver off of the low-frequency driver.

27. The one or more non-transitory computer-readable media according to claim 24 , wherein the instructions, when executed by a system, cause the system to:

compute an audio waveform to cancel high-frequency waveforms reflected off of the low- frequency driver.

28. The one or more non-transitory computer-readable media according to claim 24 , wherein the instructions, when executed by a system, cause the system to:

drive the first frequency band to the low-frequency driver unmodified.

29. One or more non-transitory computer-readable media having instructions stored thereon, wherein the instructions, when executed by a system, cause the system to:

separate a low-frequency band from a high-frequency band;

estimate, based at least on the low-frequency band, an expected excursion of a woofer in response to the low-frequency band;

compute an adjustment to the high-frequency band to compensate for reflection of a high- frequency audio signal from a tweeter off of the woofer moving at the estimated excursion;

drive the low-frequency band to the woofer; and

drive the adjusted high-frequency band to the tweeter.

30. The one or more non-transitory computer-readable media according to claim 29 , wherein the instructions, when executed by a system, cause the system to:

drive the low-frequency band to the woofer unadjusted.

31. The one or more non-transitory computer-readable media according to claim 29 , wherein the instructions, when executed by a system, cause the system to:

compute a Doppler compensation for reflection of audio waveforms from the tweeter off of the woofer.

32. The one or more non-transitory computer-readable media according to claim 29 , wherein the instructions, when executed by a system, cause the system to:

cancel high-frequency waveforms that are reflected off of the woofer.

33. The one or more non-transitory computer-readable media according to claim 29 , wherein the system comprises the tweeter being concentric with the woofer.

34. The one or more non-transitory computer-readable media according to claim 29 , wherein the instructions, when executed by a system, cause the system to:

compute an audio waveform to cancel high-frequency waveforms reflected off of the woofer.

35. The one or more non-transitory computer-readable media according to claim 29 , wherein the system comprises the tweeter being offset from the woofer.

36. The one or more non-transitory computer-readable media according to claim 29 , wherein the system comprises two independent drivers and the woofer is a mid-to-low frequency woofer and the tweeter is a high-frequency tweeter.

37. The one or more non-transitory computer-readable media according to claim 29 , wherein time shifting is applied to one or more high-frequency audio signals to compensate for misalignment of a plurality of acoustic centers of a plurality of drivers.

38. The one or more non-transitory computer-readable media according to claim 29 , wherein information about one or more high-frequency signals and their expected interaction with the woofer are provided to the tweeter.

39. The one or more non-transitory computer-readable media according to claim 29 , wherein a predistortion is inserted into one or more signals to the tweeter for canceling one or more reflected high-frequency waves.