Robust crosstalk cancellation using a speaker array

Patent metadata

Field	Value
Publication number	US-9756446-B2
Application number	US-201414773280-A
Country	US
Kind code	B2
Filing date	Mar 13, 2014
Priority date	Mar 14, 2013
Publication date	Sep 5, 2017
Grant date	Sep 5, 2017

Abstract

An audio receiver that performs crosstalk cancellation using a speaker array is described. The audio receiver detects the location of a listener in a room and processes a piece of sound program content to be output through the speaker array using one or more beam pattern matrices. The beam pattern matrices are generated according to one or more constraints. The constraints may include increasing a right channel and decreasing a left channel at the right ear of the listener, increasing a left channel and decreasing a right channel at the left ear of the listener, and decreasing sound in all other areas of the room. These constraints cause the audio receiver to beam sound primarily towards the listener and not in other areas of the room such that crosstalk cancellation is achieved with minimal effects due to changes to the frequency response of the room. Other embodiments are also described.

First claim

What is claimed is:

1. A method of performing crosstalk cancellation, comprising:
identifying a location of a listener in a room;
retrieving a previously stored set of beam pattern matrices corresponding to the identified location of the listener from a storage that contains a plurality of beam pattern matrices, each of the plurality of beam pattern matrices corresponding to a particular audio frequency, and each of the plurality of beam pattern matrices having been compensated for effects caused by test sounds propagating through the room during the generation of the plurality of beam pattern matrices using a transfer function for the room; and
driving a speaker array to produce a set of beam patterns based on the retrieved beam pattern matrices, wherein the retrieved beam pattern matrices cause the beam patterns to (1) increase a left channel and decrease a right channel of a piece of sound program content at the left ear of the listener, (2) increase the right channel and decrease the left channel at the right ear of the listener, and (3) decrease sound power in all other areas of the room.

2. The method of claim 1 , wherein identifying the location of the listener in the room comprises performing face detection and tracking.

3. The method of claim 1 , further comprising:
repeatedly identifying the location of the listener in the room while the piece of sound program content continues to be played back.

4. The method of claim 3 , further comprising:
upon determining that the listener has moved to a different location in the room based on the repeated identification, retrieving a new set of beam pattern matrices corresponding to the different location of the listener.

5. The method of claim 4 , further comprising:
driving the speaker array to produce a set of beam patterns based on the retrieved new set of beam pattern matrices.

6. The method of claim 1 , wherein each beam pattern matrix is a set of filter values corresponding to a frequency for driving each transducer in the speaker array.

7. The method of claim 1 , wherein the plurality of beam pattern matrices in the storage each correspond to distinct locations in the room relative to the speaker array and an audio frequency.

8. The method of claim 7 , wherein the plurality of beam pattern matrices are preset during manufacture of the speaker array.

9. A method for generating a beam pattern matrix that causes a speaker array to provide a beam pattern corresponding to a particular audio frequency, comprising:
positioning a first set of microphones in a room, wherein the first set of microphones are positioned to simulate a location of the left ear of a listener;
positioning a second set of microphones in the room, wherein the second set of microphones are positioned to simulate a location of the right ear of the listener;
positioning a third set of microphones in the room separate from the first and second sets of microphones;
driving a speaker array with a left audio channel and a right audio channel;
determining a set of beam patterns that (1) maximize the left audio channel and minimizes the right audio channel at the first set of microphones, (2) maximize the right audio channel and minimizes the left audio channel at the second set of microphones, (3) and minimizes sound sensed by the third set of microphones;
determining a transfer function for the room; and
generating the beam pattern matrix to represent the beam patterns as a set of real values for driving the speaker array for a particular frequency, utilizing the transfer function during the generation of the beam pattern matrix to compensate for effects caused by the right audio channel and the left audio channel propagating through the room.

10. The method of claim 9 , further comprising:
repositioning the first, second, and third sets of microphones to simulate a new location of the listener in the room;
determining a new set of beam patterns that (1) increase the left audio channel and decrease the right audio channel at the first set of microphones, (2) increase the right audio channel and decrease the left audio channel at the second set of microphones, and (3) decrease sound sensed by the third set of microphones; and
generating a new beam pattern matrix to represent the new set of beam patterns as a set of real values for driving the speaker array for a particular frequency.

11. The method of claim 9 , further comprising:
providing the beam pattern matrix to an audio device for use in a different room.

12. The method of claim 9 , wherein the set of beam patterns are determined using a least squares algorithm, where a large weight is applied to maximizing and minimizing the left and right audio channels at the first and second sets of microphones, respectively, and a smaller weight is applied to the third set of microphones.

13. The method of claim 9 , wherein the transfer function for the room is determined corresponding to the location of the listener.

14. A system for generating a beam pattern matrix that causes a speaker array to provide a beam pattern corresponding to a particular audio frequency, comprising:
a first set of microphones representing the left ear of a listener, wherein the listener is located in a room;
a second set of microphones representing the right ear of the listener;
a third set of microphones representing other areas of a room in which the listener is located; and
an audio processor for determining a set of beam patterns for a speaker array that produce a left audio channel at the first set of microphones and a right audio channel at the second set of microphones while minimizing sound sensed by the third set of microphones, wherein the audio processor determines a transfer function for the room, generates the beam pattern matrix to represent the beam patterns as a set of real values for driving the speaker array, and utilizes the transfer function during the generation of the beam pattern matrix to compensate for effects caused by the right audio channel and the left audio channel propagating through the room.

15. The system of claim 14 , wherein the set of beam patterns are determined by the audio processor using a least squares algorithm, where a large weight is applied to producing the left audio channel at the first set of microphones and the right audio channel at the second set of microphones while a smaller weight is applied to the third set of microphones.

16. The system of claim 15 , further comprising:
a transmission unit for transmitting the beam pattern matrix to an external device for use in a different room.

17. The system of claim 14 , wherein the transfer function for the room is determined corresponding to the location of the listener.

18. An article of manufacture, comprising:
a machine-readable storage medium that stores instructions which, when executed by a processor in a computing device,
identify a location of a listener in a room;
retrieve a previously stored beam pattern matrix corresponding to the identified location of the listener from a storage that contains a plurality of beam pattern matrices, each of the plurality of beam pattern matrices corresponding to a particular audio frequency, and each of the plurality of beam pattern matrices having been compensated for effects caused by test sounds propagating through the room during the generation of the plurality of beam pattern matrices using a transfer function for the room; and
drive a speaker array to produce a set of beam patterns based on the retrieved beam pattern matrix, wherein the retrieved be

Assignees

• Apple Inc

Inventors

• Johnson Martin E
• Isaac Ronald N

Classifications

• H04R5/04

  Circuit arrangements, {e.g. for selective connection of amplifier inputs/outputs to loudspeakers, for loudspeaker detection, or for adaptation of settings to personal preferences or hearing impairments (combinations of amplifiers H03F3/68; stereophonic systems H04S)} · CPC title

• H04S3/02

  of the matrix type, i.e. in which input signals are combined algebraically, e.g. after having been phase shifted with respect to each other · CPC title

• H04R2203/12

  Beamforming aspects for stereophonic sound reproduction with loudspeaker arrays · CPC title

• H04R5/02

  Spatial or constructional arrangements of loudspeakers · CPC title

• H04S7/303

  Tracking of listener position or orientation · CPC title