Audio adaptation to room

• US 10,244,314 B2
• Filed: 06/29/2017
• Issued: 03/26/2019
• Est. Priority Date: 06/02/2017
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Kriegel, Adam E., Family, Afrooz, Ramprashad, Sean A., Choisel, Sylvain J.
• Primary Examiner(s): Paul, Disler
• Application Number:
  US15/636,967
• Publication Number:
  US 20180352333A1
• Time in Patent Office: 635 Days
• Field of Search: 381 58, 381104-109, 381103, 381 59
• CPC Class Codes: G10L 2021/02082 the noise being echo, reverberation of the speech
• CPC Class Codes: G10L 21/0208 Noise filtering
• CPC Class Codes: H04R 1/403 loud-speakers
• CPC Class Codes: H04R 2227/005 Audio distribution systems for home, i.e. multi-room use
• CPC Class Codes: H04R 27/00 Public address systems circuits for preventing acoustic reaction H04R3/02; circuits for distributing signals to loudspeakers H04R3/12; monitoring or testing arrangements for public address systems H04R29/007; amplifiers H03F
• CPC Class Codes: H04R 29/002 Loudspeaker arrays
• CPC Class Codes: H04R 29/007 for public address systems public address systems per se H04R27/00
• CPC Class Codes: H04R 3/04 for correcting frequency response
• CPC Class Codes: H04R 3/12 for distributing signals to two or more loudspeakers specially adapted for hearing aids H04R25/407
• CPC Class Codes: H04S 7/305 Electronic adaptation of stereophonic audio signals to reverberation of the listening space H04S7/301 takes precedence
• CPC Class Codes: H04S 7/307 Frequency adjustment, e.g. tone control H04S7/301 takes precedence

Abstract

An audio system includes one or more loudspeaker cabinets, each having loudspeakers. The system outputs an omnidirectional sound pattern to determine the acoustic environment. Sensing logic determines an acoustic environment of the loudspeaker cabinets. The sensing logic may include an echo canceller. A playback mode processor adjusts an audio program according to a playback mode determined from the acoustic environment of the audio system. The system may produce a directional pattern superimposed on an omnidirectional pattern, if the acoustic environment is in free space. The system may aim ambient content toward a wall and direct content away from the wall, if the acoustic environment is not in free space. The sensing logic automatically determines the acoustic environment upon initial power up and when position changes of loudspeaker cabinets are detected. Accelerometers may detect position changes of the loudspeaker cabinets.

Claims

1. An audio system comprising:

a loudspeaker cabinet, having integrated therein a plurality of loudspeaker drivers coupled to be driven by an audio power amplifier subsystem and a microphone on an exterior of the loudspeaker cabinet;

a playback mode processor to receive an audio program, adjust the audio program according to a playback mode determined from an acoustic environment of the loudspeaker cabinet, produce driver input audio signals for the plurality of loudspeaker drivers to output portions of the audio program in particular directions from the loudspeaker cabinet according to the adjusted audio program, and provide the driver input audio signals to the audio power amplifier subsystem to output the adjusted audio program through the plurality of loudspeaker drivers in the loudspeaker cabinet;

sensing logic to cause the playback mode processor to output an omnidirectional sound pattern through the plurality of loudspeaker drivers in the loudspeaker cabinet, to collect a plurality of measurements from the microphone on the exterior of the loudspeaker cabinet over a first period of time, each of the plurality of measurements being for a second period of time that is shorter than the first period of time, to compare each of the plurality of measurements to a target level and to determine a proportion of the plurality of measurements that meet the target level, and to determine the acoustic environment of the loudspeaker cabinet includes a wall or a bookshelf close to the loudspeaker cabinet only if the proportion of the plurality of measurements that meet the target level is above a threshold value.

2. The audio system of claim 1, wherein the sensing logic includes an echo canceller to estimate an acoustic path between the plurality of loudspeaker drivers in the loudspeaker cabinet and the microphone on the exterior of the loudspeaker cabinet, and determine the acoustic environment of the loudspeaker cabinet.

3. The audio system of claim 1, wherein the second period of time is between 10 milliseconds and 500 milliseconds and the first period of time is at least ten times the second period of time.

4. The audio system of claim 1, further comprising a low frequency correction filter to receive the audio program, produce the driver input audio signals that correct the audio program for room effects for the loudspeaker cabinet, responsive to the acoustic environment of the loudspeaker cabinet, and provide the driver input audio signals to the audio power amplifier subsystem to output the corrected audio program through the plurality of loudspeaker drivers in the loudspeaker cabinet.

5. The audio system of claim 1, wherein if the acoustic environment includes a wall or a bookshelf close to the loudspeaker cabinet, the playback mode processor adjusts the audio program to produce a directional pattern superimposed on an omnidirectional pattern.

6. The audio system of claim 1, wherein if the acoustic environment includes a wall or a bookshelf close to the loudspeaker cabinet, the playback mode processor adjusts the audio program to aim ambient content of the audio program toward the wall or the bookshelf, and to aim direct content of the audio program away from the wall or the bookshelf.

7. The audio system of claim 1, wherein the sensing logic configures the driver input audio signals to output a low frequency sound pattern through the plurality of loudspeaker drivers to determine a direction of an obstacle.

8. The audio system of claim 1, wherein the sensing logic automatically determines the acoustic environment of the audio system upon initial power up of the audio system and when a change in a position of the loudspeaker cabinet is detected.

9. The audio system of claim 8, further comprising an accelerometer coupled to the loudspeaker cabinet to detect the change in the position of the loudspeaker cabinet.

10. The audio system of claim 1, wherein the sensing logic automatically detects a change in a position of the loudspeaker cabinet and re-determines the acoustic environment of the loudspeaker cabinet, and the adjustment of the audio program by the playback mode processor is responsive to the re-determined acoustic environment of the loudspeaker cabinet.

11. A method for outputting an audio program through a plurality of loudspeaker drivers in a loudspeaker cabinet, the method comprising:

determining an acoustic environment of the loudspeaker cabinet, the determination including

outputting an omnidirectional sound pattern through the plurality of loudspeaker drivers,

collecting a plurality of measurements from a microphone on the exterior of the loudspeaker cabinet over a first period of time, each of the plurality of measurements being for a second period of time that is shorter than the first period of time,

comparing each of the plurality of measurements to a target level to determine a proportion of the plurality of measurements that meet the target level, and

only if the proportion of the plurality of measurements that meet the target level is above a threshold value, determining the acoustic environment of the loudspeaker cabinet includes a wall or a bookshelf close to the loudspeaker cabinet;

determining a playback mode based on the acoustic environment of the loudspeaker cabinet;

adjusting the audio program to produce a plurality of audio signals; and

outputting the plurality of audio signals through the plurality of loudspeaker drivers in the loudspeaker cabinet, wherein portions of the audio program are output in particular directions from the loudspeaker cabinet according to the playback mode.

12. The method of claim 11, wherein determining the acoustic environment of the plurality of loudspeaker drivers further comprises estimating an acoustic path between the plurality of loudspeaker drivers in the loudspeaker cabinet and the microphone on the exterior of the loudspeaker cabinet using an echo canceller.

13. The method of claim 11, wherein the second period of time is between 10 milliseconds and 500 milliseconds and the first period of time is at least ten times the second period of time.

14. The method of claim 11 further comprising:

determining a low frequency correction filter to correct for room effects responsive to the acoustic environment of the loudspeaker cabinet; and

applying the low frequency correction filter to the audio program to correct the plurality of audio signals.

15. The method of claim 11, wherein if the acoustic environment includes a wall or a bookshelf close to the loudspeaker cabinet, the playback mode produces a directional pattern superimposed on an omnidirectional pattern.

16. The method of claim 11, wherein if the acoustic environment includes a wall or a bookshelf close to the loudspeaker cabinet, the playback mode aims ambient content of the audio program toward the wall or the bookshelf, and aims direct content of the audio program away from the wall or the bookshelf.

17. The method of claim 11, wherein determining the acoustic environment of the loudspeaker cabinet comprises determining a direction of an obstacle using a low frequency sound pattern.

18. The method of claim 11, wherein the determining the acoustic environment of the loudspeaker cabinet is automatically performed upon initial power up of the loudspeaker cabinet and when a change in a position of the loudspeaker cabinet is detected.

19. The method of claim 18, wherein the change in the position of the loudspeaker cabinet is detected using an accelerometer.

20. The method of claim 11 further comprising:

determining whether a change in position of the loudspeaker cabinet has occurred;

in accordance with a determination that the change in position has occurred,

determining the acoustic environment of the loudspeaker cabinet,

determining the playback mode based on the acoustic environment of the loudspeaker cabinet, wherein the plurality of audio signals are output through the plurality of loudspeaker drivers according to the playback mode,

adjusting the audio program to produce the plurality of audio signals that output portions of the audio program in particular directions from the loudspeaker cabinet, and

outputting the plurality of audio signals through the plurality of loudspeaker drivers.

21. An article of manufacture comprising a machine-readable non-transitory medium having instructions stored therein that, when executed by a processor:

determine an acoustic environment of a loudspeaker cabinet having a plurality of loudspeaker drivers therein, the determination including

outputting an omnidirectional sound pattern through the plurality of loudspeaker drivers,

collecting a plurality of measurements from a microphone on the exterior of the loudspeaker cabinet over a first period of time, each of the plurality of measurements being for a second period of time that is shorter than the first period of time,

comparing each of the plurality of measurements to a target level to determine a proportion of the plurality of measurements that meet the target level, and

only if the proportion of the plurality of measurements that meet the target level is above a threshold value, determining the acoustic environment of the loudspeaker cabinet includes a wall or a bookshelf close to the loudspeaker cabinet;

determine a playback mode based on the acoustic environment of the loudspeaker cabinet;

adjust an audio program to produce a plurality of audio signals; and

output the plurality of audio signals through the plurality of loudspeaker drivers in the loudspeaker cabinet, wherein portions of the audio program are output in particular directions from the loudspeaker cabinet according to the playback mode.

22. The article of manufacture of claim 21, wherein the machine-readable non-transitory medium has additional instructions stored therein that, when executed by the processor:

determine a low frequency correction filter to correct for room effects responsive to the acoustic environment of the loudspeaker cabinet; and

apply the low frequency correction filter to the audio program to produce the plurality of audio signals.

23. The article of manufacture of claim 21, wherein the machine-readable non-transitory medium has additional instructions stored therein that, when executed by the processor:

if the acoustic environment includes a wall or a bookshelf close to the loudspeaker cabinet, produce the plurality of audio signals as defining a directional pattern superimposed on an omnidirectional pattern.

24. The article of manufacture of claim 21, wherein the machine-readable non-transitory medium has additional instructions stored therein that, when executed by the processor:

if the acoustic environment includes a wall or a bookshelf close to the loudspeaker cabinet,

aim ambient content of the audio program toward the wall or the bookshelf, and

aim direct content of the audio program away from the wall or the bookshelf.

25. The article of manufacture of claim 21, wherein the machine-readable non-transitory medium has additional instructions stored therein that, when executed by the processor, automatically determine the acoustic environment of the loudspeaker cabinet upon initial power up of the processor and when a change in a position of the loudspeaker cabinet is detected.