Audio adaptation to room

• US 10,299,039 B2
• Filed: 06/02/2017
• Issued: 05/21/2019
• 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:
  US15/613,049
• Publication Number:
  US 20180352331A1
• Time in Patent Office: 718 Days
• Field of Search: 381 58- 59, 381103
• 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. Sensing logic determines an acoustic environment of the loudspeaker cabinets. The sensing logic may include an echo canceller. A low frequency filter corrects an audio program based on the acoustic environment of the loudspeaker cabinets. The system outputs an omnidirectional sound pattern, which may be low frequency sound, to determine the acoustic environment. 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:

one or more loudspeaker cabinets, having integrated therein one or more loudspeaker drivers;

one or more audio amplifiers, an output of each of the one or more audio amplifiers is coupled to an input of one of the one or more loudspeaker drivers;

sensing logic to determine an acoustic environment of each of the one or more loudspeaker cabinets;

a low frequency correction filter to receive an audio program, produce one or more audio signals that correct the audio program for room effects for each of the one or more loudspeaker cabinets, responsive to the acoustic environment of each of the one or more loudspeaker cabinets, and provide the one or more audio signals to one or more of the audio amplifiers to output the corrected audio program through one or more of the loudspeaker drivers in each of the one or more loudspeaker cabinets; and

a playback mode processor to receive the audio program and produce one or more audio signals that are provided to one or more of the audio amplifiers in each of the loudspeaker cabinets, and adjust the audio program to aim ambient content of the audio program toward a wall and to aim direct content of the audio program away from the wall responsive to the sensing logic having determined that the acoustic environment is not in free space.

2. The audio system of claim 1, wherein the sensing logic produces audio signals having an omnidirectional sound pattern and provides the audio signals having the omnidirectional sound pattern to one or more of the audio amplifiers to output the omnidirectional sound pattern through one or more loudspeaker drivers in each of the one or more loudspeaker cabinets to determine the acoustic environment of each of the one or more loudspeaker cabinets.

3. The audio system of claim 2, wherein the sensing logic includes an echo canceller to estimate an acoustic path between the one or more loudspeaker drivers in each of the one or more loudspeaker cabinets and one or more microphones on the exterior of each of the one or more loudspeaker cabinets and determine the acoustic environment of each of the one or more loudspeaker cabinets.

4. The audio system of claim 3, wherein the sensing logic:

collects a plurality of measurements from each of the one or more microphones 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;

compares 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

disables application of the low frequency correction filter and determination of the acoustic environment of the audio system when the proportion of the plurality of measurements that meet the target level is below a threshold value.

5. The audio system of claim 4, 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.

6. The audio system of claim 1, wherein the playback mode processor further adjusts the audio program to produce audio signals that are provided to a plurality of the audio amplifiers and that yield a directional pattern superimposed on an omnidirectional pattern, responsive to determining that the acoustic environment is in free space.

7. The audio system of claim 1, wherein the sensing logic produces one or more audio signals having a low frequency sound pattern and provides the one or more audio signals having the low frequency sound pattern to one or more of the audio amplifiers to output the low frequency sound pattern through the one or more 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 when a change in a position of the one or more loudspeaker cabinets is detected.

9. The audio system of claim 8, further comprising one or more accelerometers, each of the one or more accelerometers coupled to a different one of the one or more loudspeaker cabinets to detect the change in the position of the one or more loudspeaker cabinets.

10. The audio system of claim 1, wherein the sensing logic automatically detects a change in a position of one of the loudspeaker cabinets and re-determines the acoustic environment of the changed loudspeaker cabinet, and the low frequency correction filter is responsive to the re-determined acoustic environment of the changed loudspeaker cabinet.

11. A method performed by a device to output an audio program through one or more speakers in the device, the method comprising:

determining an acoustic environment of the one or more speakers, by outputting an omnidirectional sound pattern through the one or more speakers, estimating an acoustic path between the one or more speakers and a microphone using an echo canceller,

collecting a plurality of measurements from the microphone over a first period of time, each of the plurality of measurements being for a second period of time, the first period of time being at least ten times the second period of time, and

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;

when the proportion of the plurality of measurements that meet the target level is above a threshold value,

determining a low frequency correction filter to correct for room effects responsive to the acoustic environment of the one or more speakers, and

applying the low frequency correction filter to the audio program to produce one or more audio signals; and

outputting the one or more audio signals through the one or more speakers in the device.

12. 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.

13. The method of claim 11 further comprising determining a playback mode based on the acoustic environment of the one or more speakers, wherein the one or more audio signals are output through the one or more speakers according to the playback mode.

14. The method of claim 13, wherein the playback mode produces a directional pattern superimposed on an omnidirectional pattern, when the acoustic environment of the one or more speakers is in free space.

15. The method of claim 13, wherein the playback mode directs ambient content of the audio program toward a wall and direct content of the audio program away from the wall, when the acoustic environment of the one or more speakers is not in free space.

16. The method of claim 11, wherein determining the acoustic environment of the one or more speakers comprises determining a direction of an obstacle using a low frequency sound pattern.

17. The method of claim 11, wherein the determining the acoustic environment of the one or more speakers is automatically performed upon initial power up of the device and when a change in a position of the one or more speakers is detected.

18. The method of claim 17, wherein the change in the position of the one or more speakers is detected using an accelerometer.

19. The method of claim 11 further comprising:

determining whether a change in position of the one or more speakers has occurred;

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

determining the acoustic environment of the one or more speakers,

determining the low frequency correction filter to correct for room effects responsive to the acoustic environment of the one or more speakers,

applying the low frequency correction filter to the audio program to produce the one or more audio signals, and

outputting the one or more audio signals through the one or more speakers.

20. 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 one or more speakers;

determine a low frequency correction filter to correct for room effects responsive to the acoustic environment of the one or more speakers;

apply the low frequency correction filter to an audio program to produce one or more audio signals;

determine when the acoustic environment is in free space;

when the acoustic environment is in free space, then adjust the audio program to produce a directional pattern superimposed on an omnidirectional pattern as the one or more audio signals;

determine when the acoustic environment is not in free space;

adjust the audio program to aim ambient content of the audio program toward a wall and to aim direct content of the audio program away from the wall, as the one or more audio signals, responsive to determining that the acoustic environment is not in free space; and

output the one or more audio signals through the one or more speakers.

21. The article of manufacture of claim 20, wherein the machine-readable non-transitory medium has additional instructions stored therein that, when executed by the processor:

produce an omnidirectional sound pattern;

output the omnidirectional sound pattern through the one or more speakers to determine the acoustic environment of the one or more speakers; and

in response to detecting a change in a position of the of the one or more speakers, fade back to the omnidirectional sound pattern the output of the one or more audio signals through the one or more speakers, and re-determine the acoustic environment.

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:

collects a plurality of measurements from each of the one or more microphones 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;

compares 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

disables application of the low frequency correction filter and determination of the acoustic environment of the audio system when the proportion of the plurality of measurements that meet the target level is below a threshold value.

23. The article of manufacture of claim 20, wherein the machine-readable non-transitory medium has additional instructions stored therein that, when executed by the processor:

determine a playback mode based on the acoustic environment of the one or more speakers;

adjust the one or more audio signals for the playback mode determined from the acoustic environment of the one or more speakers; and

output the one or more adjusted audio signals through the one or more speakers.

24. The article of manufacture of claim 20, 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 one or more speakers upon initial power up of the processor and when a change in a position of the one or more speakers is detected.