Facilitating calibration of an audio playback device

• US 10,127,006 B2
• Filed: 09/24/2015
• Issued: 11/13/2018
• Est. Priority Date: 09/09/2014
• Status: Active Grant

• Current Assignee: Sonos, Inc.
• Original Assignee: Sonos, Inc.
• Inventors: Sheen, Timothy W.
• Primary Examiner(s): Tsang, Fan S
• Assistant Examiner(s): Siegel, David
• Application Number:
  US14/864,393
• Publication Number:
  US 20170083279A1
• Time in Patent Office: 1,146 Days
• CPC Class Codes: G06F 3/165 Management of the audio stream, e.g. setting of volume, audio stream path
• CPC Class Codes: H03G 5/005 of digital signals
• CPC Class Codes: H03G 5/165 Equalizers; Volume or gain control in limited frequency bands
• CPC Class Codes: H04R 2227/005 Audio distribution systems for home, i.e. multi-room use
• CPC Class Codes: H04R 29/007 for public address systems public address systems per se H04R27/00
• CPC Class Codes: H04S 2420/07 Synergistic effects of band splitting and sub-band processing
• CPC Class Codes: H04S 7/301 Automatic calibration of stereophonic sound system, e.g. with test microphone
• CPC Class Codes: H04S 7/307 Frequency adjustment, e.g. tone control H04S7/301 takes precedence

Abstract

An example method, and example devices and computer-readable media related to the example method, are disclosed herein. The method includes, as a computing device is moving within an environment of a playback device, capturing, via a microphone of the computing device, one or more calibration sounds played by the playback device. The method further includes identifying one or more sections of data such that each of the one or more sections of the data correspond to a respective calibration sound of the one or more calibration sounds and using the one or more sections of the data to determine a frequency response of the playback device. The method further includes determining one or more parameters of an audio processing algorithm based on the frequency response of the playback device and a target frequency response, and sending, to the playback device, the one or more parameters.

Claims

1. A non-transitory computer-readable medium storing instructions that, when executed by a computing device, cause the computing device to perform functions comprising:

as the computing device is moving within an environment of a playback device, capturing, via a microphone of the computing device, a series of calibration sounds played by the playback device, wherein each of the calibration sounds includes a first component that includes calibration noise at frequencies between a minimum of a calibration frequency range and a first threshold frequency and a second component that includes a chirp signal sweeping through frequencies between a second threshold frequency and a maximum of the calibration frequency range;

generating data representing the calibration sounds;

identifying one or more sections of the data such that each of the one or more sections of the data corresponds to a respective calibration sound of the calibration sounds;

using the one or more sections of the data to determine a frequency response of the playback device over the calibration frequency range, wherein the frequency response of the playback device characterizes audio playback by the playback device as influenced by acoustic characteristics of the environment of the playback device;

determining one or more parameters of an audio processing algorithm based on the frequency response of the playback device and a target frequency response; and

sending, to the playback device, the one or more parameters of the audio processing algorithm.

2. The non-transitory computer-readable medium of claim 1,

wherein the calibration sounds are separated in time from a subsequent calibration sound of the calibration sounds by a guard band comprising the first component, and

wherein the guard band does not include the second component.

3. The non-transitory computer-readable medium of claim 2, wherein identifying the one or more sections of the data comprises:

identifying a first section of the data that corresponds to the guard band; and

identifying a second section of the data that corresponds to a given calibration sound based on (i) the identified first section of the data and (ii) a predetermined periodicity of the calibration sounds.

4. The non-transitory computer-readable medium of claim 2,

wherein the guard band is a first guard band,

wherein the calibration sounds are separated in time from a preceding calibration sound of the calibration sounds by a second guard band comprising the first component,

wherein the second guard band does not include the second component, and

wherein identifying the one or more sections of the data comprises:

identifying a first section of the data that corresponds to the first guard band;

identifying a second section of the data that corresponds to the second guard band; and

identifying a third section of the data that corresponds to a given calibration sound based on the identified first section of the data and the identified second section of the data.

5. The non-transitory computer-readable medium of claim 2, wherein identifying the one or more sections of the data comprises:

identifying a given section of the data representing a signal-to-noise ratio (SNR) that is greater than a threshold SNR, wherein the SNR represented by the given section of the data is a ratio of (i) a signal level of (a) a given calibration sound and/or (b) the guard band to (ii) background noise detected by the microphone within the environment of the playback device;

identifying a subsection of the given section of data that represents the guard band by identifying a subsection of the given section of data that represents a sound intensity that is less than a threshold sound intensity; and

identifying the one or more sections of the data based on (i) the identified subsection of the given section of data and (ii) a predetermined periodicity of the calibration sounds.

6. The non-transitory computer-readable medium of claim 2, the functions further comprising:

determining a signal-to-noise ratio (SNR) of a given section of the one or more sections of the data, wherein the SNR of the given section of the data is a ratio of (i) a signal level of (a) a given calibration sound and/or (b) the guard band to (ii) background noise detected by the microphone within the environment of the playback device;

determining that the SNR of the given section exceeds a threshold SNR; and

based on determining that the SNR of the given section exceeds the threshold SNR, using the given section to determine the frequency response of the playback device.

7. The non-transitory computer-readable medium of claim 2, wherein the guard band includes both a first audio frequency and a second audio frequency at a particular time, the functions further comprising:

detecting the first audio frequency and the second audio frequency at the particular time,

wherein identifying the one or more sections of the data comprises identifying the one or more sections of the data based on (i) detecting the first audio frequency and the second audio frequency at the particular time and (ii) a predetermined periodicity of the calibration sounds.

8. The non-transitory computer-readable medium of claim 1, wherein using the one or more sections of the data to determine the frequency response of the playback device comprises:

converting the one or more sections of the data from a time-domain format to a frequency-domain format; and

using the converted one or more sections of the data to determine the frequency response of the playback device.

9. The non-transitory computer-readable medium of claim 8, wherein using the converted one or more sections of the data to determine the frequency response of the playback device comprises calculating a sum of magnitudes of captured audio, over the calibration frequency range, of the converted one or more sections of the data.

10. The non-transitory computer-readable medium of claim 9, wherein calculating the sum of the converted one or more sections of the data comprises:

prior to capturing a given calibration sound, calculating an initial sum of (i) a first converted section of the one or more converted sections of the data and (ii) a second converted section of the one or more converted sections of the data; and

after calculating the initial sum, calculating a revised sum of (i) the first sum and (ii) a third converted section of the one or more converted sections of the data corresponding to the given calibration sound.

11. The non-transitory computer-readable medium of claim 8, wherein using the converted one or more sections of the data to determine the frequency response of the playback device comprises normalizing the converted one or more sections of the data so that each of the one or more normalized sections of the data represent a common amount of energy over a normalization frequency range.

12. The non-transitory computer-readable medium of claim 8, wherein using the converted one or more sections of the data to determine the frequency response of the playback device comprises weighting the one or more converted sections of the data based on amounts of energy respectively represented by the one or more converted sections of the data over a normalization frequency range.

13. The non-transitory computer-readable medium of claim 1, wherein using the one or more sections of the data to determine the frequency response of the playback device comprises:

processing the one or more sections of the data based on a frequency response of the microphone of the computing device; and

using the one or more processed sections of the data to determine the frequency response of the playback device.

14. The non-transitory computer-readable medium of claim 13, the functions further comprising:

converting the one or more sections of the data from a time-domain format to a frequency-domain format,

wherein processing the one or more sections of the data comprises processing the one or more converted sections of the data.

15. The non-transitory computer-readable medium of claim 1, wherein determining the one or more parameters of the audio processing algorithm comprises determining the one or more parameters of the audio processing algorithm such that, when the audio processing algorithm is implemented by the playback device, no portion of audio played by the playback device is amplified by more than a threshold amplification factor.

16. The non-transitory computer-readable medium of claim 1, the functions further comprising:

capturing, via the microphone, one or more additional calibration sounds played by the playback device by implementing the audio processing algorithm; and

based on the captured one or more additional calibration sounds, determining that the playback device is properly calibrated.

20. The non-transitory computer-readable medium of claim 1, wherein identifying one or more sections of the data comprises identifying one or more sections of the data based on respective phase shifts indicated by the respective chirp signals of the calibration sounds.

17. A non-transitory computer-readable medium storing instructions that, when executed by a computing device, cause the computing device to perform functions comprising:

capturing, via a microphone of the computing device, one or more calibration sounds played by a playback device, wherein each of the calibration sounds includes a first component that includes calibration noise at frequencies between a minimum of a calibration frequency range and a first threshold frequency and a second component that includes a chirp signal sweeping through frequencies between a second threshold frequency and a maximum of the calibration frequency range;

generating data representing the one or more calibration sounds;

based on respective phase shifts indicated by the respective chirp signals of the calibration sounds, identifying one or more sections of the data such that each of the one or more sections of the data corresponds to a respective calibration sound of the one or more calibration sounds;

determining that more than a threshold amount of sections of the one or more sections of the data correspond to respective signal-to-noise ratios (SNRs) that are less than a threshold signal-to-noise ratio; and

providing an indication, via a user interface of the computing device, that the playback device was not properly calibrated.

18. A non-transitory computer-readable medium storing instructions that, when executed by a computing device, cause the computing device to perform functions comprising:

as the computing device is moving within an environment of a first playback device and a second playback device, capturing, via a microphone of the computing device, one or more first calibration sounds played by the first playback device and one or more second calibration sounds played by the second playback device, wherein each of the one or more first calibration sounds and each of the one or more second calibration sounds includes a sweep through frequencies of a calibration frequency range;

generating data representing the one or more first calibration sounds and the one or more second calibration sounds;

identifying (i) one or more first sections of the data such that each of the one or more first sections of the data corresponds to a respective calibration sound of the one or more first calibration sounds and (ii) one or more second sections of the data such that each of the one or more second sections of the data corresponds to a respective calibration sound of the one or more second calibration sounds;

using the one or more first sections of the data to determine a first frequency response of the first playback device over the calibration frequency range, wherein the first frequency response characterizes audio playback by the first playback device as influenced by acoustic characteristics of the environment of the first playback device and the second playback device;

using the one or more second sections of the data to determine a second frequency response of the second playback device over the calibration frequency range, wherein the second frequency response characterizes audio playback by the second playback device as influenced by the acoustic characteristics of the environment of the first playback device and the second playback device;

determining one or more first parameters of a first audio processing algorithm based on the first frequency response and a first target frequency response;

determining one or more second parameters of a second audio processing algorithm based on the second frequency response and a second target frequency response;

sending, to the first playback device, the one or more first parameters of the first audio processing algorithm; and

sending, to the second playback device, the one or more second parameters of the second audio processing algorithm.

19. The non-transitory computer-readable medium of claim 18, wherein a given calibration sound of the one or more first calibration sounds includes both a first audio frequency and a second audio frequency at a particular time, the functions further comprising:

detecting the first audio frequency and the second audio frequency at the particular time, wherein identifying the one or more first sections of the data comprises identifying the one or more first sections of the data based on (i) detecting the first audio frequency and the second audio frequency at the particular time and (ii) a predetermined periodicity of the one or more first calibration sounds.