Systems and methods for surround sound echo reduction

1. A method for echo reduction by an electronic device, comprising:

mixing a set of runtime audio signals based on a set of acoustic paths to determine a reference signal, wherein mixing the set of runtime audio signals comprises applying one of the set of acoustic paths between a first speaker and a first microphone to a second microphone;

receiving at least one composite audio signal that is based on the set of runtime audio signals;

nulling in a direction that is in an acoustic path between a microphone array and at least one speaker based on the at least one composite audio signal; and

reducing echo in the at least one composite audio signal based on the reference signal.

2. The method of claim 1 , further comprising:

outputting a set of output calibration audio signals;

receiving a set of input calibration audio signals based on the set of output calibration audio signals; and

determining the set of acoustic paths based on the set of input calibration audio signals.

3. The method of claim 2 , wherein each of the set of output calibration audio signals is output individually in an output sequence, and wherein each of the set of input calibration audio signals is received individually in an input sequence.

4. The method of claim 1 , wherein the at least one composite audio signal is received by two or more microphones in a wireless communication device, and wherein mixing the set of runtime audio signals and reducing the echo is performed by an audio processing device.

5. The method of claim 1 , further comprising applying a first acoustic path to multiple runtime audio signals.

6. The method of claim 1 , wherein the at least one composite audio signal is received by two or more microphones in a wireless communication device, wherein a mixed-down source per each microphone is communicated, and wherein enhanced speech with echo cancellation/noise suppression is communicated.

7. The method of claim 1 , further comprising determining coefficients for a set of filters that filter speaker audio signals.

8. The method of claim 7 , wherein at least two filters share coefficients.

9. The method of claim 7 , wherein coefficients from a first filter are utilized as coefficients for a second filter.

10. The method of claim 7 , wherein at least one filter is configured to only change an amplitude and delay of an input signal.

11. The method of claim 7 , wherein at least one filter is based on an impulse response.

12. The method of claim 1 , further comprising determining whether to recalibrate based on an adaptive filter.

13. An electronic device for echo reduction, comprising:

mixing circuitry configured to mix a set of runtime audio signals based on a set of acoustic paths to determine a reference signal, wherein the mixing circuitry is configured to apply one of the set of acoustic paths between a first speaker and a first microphone to a second microphone;

two or more microphones configured to receive at least one composite audio signal that is based on the set of runtime audio signals;

beamformer circuitry configured to null in a direction that is in an acoustic path between a microphone array and at least one speaker based on the at least one composite audio signal; and

echo reduction circuitry configured to reduce echo in the at least one composite audio signal based on the reference signal.

14. The electronic device of claim 13 , further comprising:

speakers configured to output a set of output calibration audio signals, wherein the two or more microphones are configured to receive a set of input calibration audio signals based on the set of output calibration audio signals; and

acoustic path determination circuitry configured to determine the set of acoustic paths based on the set of input calibration audio signals.

15. The electronic device of claim 14 , wherein the speakers are configured to output each of the set of output calibration audio signals individually in an output sequence, and wherein the two or more microphones are configured to receive each of the set of input calibration audio signals individually in an input sequence.

16. The electronic device of claim 13 , comprising an audio processing device, wherein the audio processing device is configured to mix the set of runtime audio signals and to reduce the echo.

17. The electronic device of claim 13 , further comprising acoustic path application circuitry configured to apply a first acoustic path to multiple runtime audio signals.

18. The electronic device of claim 13 , wherein the electronic device is configured to communicate a mixed-down source per each microphone and to communicate enhanced speech with echo cancellation/noise suppression.

19. The electronic device of claim 13 , further comprising acoustic path determination circuitry configured to determine coefficients for a set of filters that filter speaker audio signals.

20. The electronic device of claim 19 , wherein at least two filters are configured to share coefficients.

21. The electronic device of claim 19 , wherein a second filter is configured to utilize coefficients from a first filter.

22. The electronic device of claim 19 , wherein at least one filter is configured to only change an amplitude and delay of an input signal.

23. The electronic device of claim 19 , wherein at least one filter is based on an impulse response.

24. The electronic device of claim 13 , further comprising recalibration circuitry configured to determine whether to recalibrate based on an adaptive filter.

25. An apparatus for echo reduction, comprising:

means for mixing a set of runtime audio signals based on a set of acoustic paths to determine a reference signal, wherein the means for mixing the set of runtime audio signals comprises means for applying one of the set of acoustic paths between a first speaker and a first microphone to a second microphone;

means for receiving at least one composite audio signal that is based on the set of runtime audio signals;

means for nulling in a direction that is in an acoustic path between a microphone array and at least one speaker based on the at least one composite audio signal; and

means for reducing echo in the at least one composite audio signal based on the reference signal.

26. The apparatus of claim 25 , further comprising:

means for outputting a set of output calibration audio signals;

means for receiving a set of input calibration audio signals based on the set of output calibration audio signals; and

means for determining the set of acoustic paths based on the set of input calibration audio signals.

27. The apparatus of claim 26 , wherein each of the set of output calibration audio signals is output individually in an output sequence, and wherein each of the set of input calibration audio signals is received individually in an input sequence.

28. The apparatus of claim 25 , wherein the means for mixing the set of runtime audio signals and the means for reducing the echo are included in an audio processing device.

29. The apparatus of claim 25 , further comprising means for applying a first acoustic path to multiple runtime audio signals.

30. The apparatus of claim 25 , wherein a mixed-down source per each microphone is communicated, and wherein enhanced speech with echo cancellation/noise suppression is communicated.

31. The apparatus of claim 25 , further comprising means for determining coefficients for a set of filters that filter speaker audio signals.

32. The apparatus of claim 31 , wherein at least two filters share coefficients.

33. The apparatus of claim 31 , wherein coefficients from a first filter are utilized as coefficients for a second filter.

34. The apparatus of claim 31 , wherein at least one filter is configured to only change the amplitude and delay of an input signal.

35. The apparatus of claim 31 , wherein at least one filter is based on an impulse response.

36. The apparatus of claim 25 , further comprising means for determining whether to recalibrate based on an adaptive filter.

37. A computer-program product for echo reduction, comprising a non-transitory tangible computer-readable medium having instructions thereon, the instructions comprising:

code for causing an electronic device to mix a set of runtime audio signals based on a set of acoustic paths to determine a reference signal, wherein the code for causing the electronic device to mix the set of runtime audio signals comprises code for causing the electronic device to apply one of the set of acoustic paths between a first speaker and a first microphone to a second microphone;

code for causing the electronic device to receive at least one composite audio signal that is based on the set of runtime audio signals;

code for causing the electronic device to null in a direction that is in an acoustic path between a microphone array and at least one speaker based on the at least one composite audio signal; and

code for causing the electronic device to reduce echo in the at least one composite audio signal based on the reference signal.

38. The computer-program product of claim 37 , further comprising:

code for causing the electronic device to output a set of output calibration audio signals;

code for causing the electronic device to receive a set of input calibration audio signals based on the set of output calibration audio signals; and

code for causing the electronic device to determine the set of acoustic paths based on the set of input calibration audio signals.

39. The computer-program product of claim 38 , wherein each of the set of output calibration audio signals is output individually in an output sequence, and wherein each of the set of input calibration audio signals is received individually in an input sequence.

40. The computer-program product of claim 37 , wherein the code for causing the electronic device to mix the set of runtime audio signals and the code for causing the electronic device to reduce the echo are included in an audio processing device.

41. The computer-program product of claim 37 , further comprising code for causing the electronic device to apply a first acoustic path to multiple runtime audio signals.

42. The computer-program product of claim 37 , wherein a mixed-down source per each microphone is communicated, and wherein enhanced speech with echo cancellation/noise suppression is communicated.

43. The computer-program product of claim 37 , further comprising code for causing the electronic device to determine coefficients for a set of filters that filter speaker audio signals.

44. The computer-program product of claim 43 , wherein at least two filters share coefficients.

45. The computer-program product of claim 43 , wherein coefficients from a first filter are utilized as coefficients for a second filter.

46. The computer-program product of claim 43 , wherein at least one filter is configured to only change an amplitude and delay of an input signal.

47. The computer-program product of claim 43 , wherein at least one filter is based on an impulse response.

48. The computer-program product of claim 37 , wherein the instructions further comprise code for causing the electronic device to determine whether to recalibrate based on an adaptive filter.

49. A method for determining a delay by an electronic device, comprising:

performing calibration by running an adaptive filter for surround sound echo reduction;

determining a delay based on an acoustic path between a microphone array and at least one speaker and based on identifying a tap number location of the adaptive filter where there is a maximum amplitude value; and

nulling the at least one speaker based on the delay, wherein the nulling is in a direction that is in the acoustic path between the microphone array and the at least one speaker.

50. The method of claim 49 , wherein nulling the at least one speaker is further based on an inter-loudspeaker delay, wherein the inter-loudspeaker delay is a difference between a time of arrival of a speaker audio signal and a time of arrival of a reference speaker audio signal.

51. The method of claim 50 , wherein the reference speaker audio signal corresponds to a speaker with a shortest delay.

52. The method of claim 50 , further comprising mixing at least two signals based on the inter-loudspeaker delay.

53. An electronic device for determining a delay, comprising:

calibration circuitry configured to perform calibration by running an adaptive filter for surround sound echo reduction and to determine a delay based on an acoustic path between a microphone array and at least one speaker and based on identifying a tap number location of the adaptive filter where there is a maximum amplitude value; and

beamforming circuitry configured to null the at least one speaker based on the delay, wherein the nulling is in a direction that is in the acoustic path between the microphone array and the at least one speaker.

54. The electronic device of claim 53 , wherein the beamforming circuitry is configured to null the at least one speaker further based on an inter-loudspeaker delay, wherein the inter-loudspeaker delay is a difference between a time of arrival of a speaker audio signal and a time of arrival of a reference speaker audio signal.

55. The electronic device of claim 54 , wherein the reference speaker audio signal corresponds to a speaker with a shortest delay.

56. The electronic device of claim 54 , further comprising mixing circuitry configured to mix at least two signals based on the inter-loudspeaker delay.

57. An apparatus for determining a delay, comprising:

means for performing calibration by running an adaptive filter for surround sound echo reduction;

means for determining a delay based on an acoustic path between a microphone array and at least one speaker and based on identifying a tap number location of the adaptive filter where there is a maximum amplitude value; and

means for nulling at least one speaker based on the delay, wherein the nulling is in a direction that is in the acoustic path between the microphone array and the at least one speaker.

58. The apparatus of claim 57 , wherein nulling the at least one speaker is further based on an inter-loudspeaker delay, wherein the inter-loudspeaker delay is a difference between a time of arrival of a speaker audio signal and a time of arrival of a reference speaker audio signal.

59. The apparatus of claim 58 , wherein the reference speaker audio signal corresponds to a speaker with a shortest delay.

60. The apparatus of claim 58 , further comprising means for mixing at least two signals based on the inter-loudspeaker delay.

61. A computer-program product for determining a delay, comprising a non-transitory tangible computer-readable medium having instructions thereon, the instructions comprising:

code for causing an electronic device to perform calibration by running an adaptive filter for surround sound echo reduction;

code for causing the electronic device to determine a delay based on an acoustic path between a microphone array and at least one speaker and based on identifying a tap number location of the adaptive filter where there is a maximum amplitude value; and

code for causing the electronic device to null the at least one speaker based on the delay, wherein the nulling is in a direction that is in the acoustic path between the microphone array and the at least one speaker.

62. The computer-program product of claim 61 , wherein nulling the at least one speaker is further based on an inter-loudspeaker delay, wherein the inter-loudspeaker delay is a difference between a time of arrival of a speaker audio signal and a time of arrival of a reference speaker audio signal.

63. The computer-program product of claim 62 , wherein the reference speaker audio signal corresponds to a speaker with a shortest delay.

64. The computer-program product of claim 62 , further comprising code for causing the electronic device to mix at least two signals based on the inter-loudspeaker delay.