Systems and methods of adjusting bass levels of multi-channel audio signals

Patent metadata

Field	Value
Publication number	US-10880671-B2
Application number	US-201916582942-A
Country	US
Kind code	B2
Filing date	Sep 25, 2019
Priority date	Mar 21, 2018
Publication date	Dec 29, 2020
Grant date	Dec 29, 2020

Abstract

Systems and methods for adjusting bass levels of a multi-channel audio signal include, among other features, (i) receiving the multi-channel signal via a playback device; (ii) separating, from the multi-channel signal, low-frequency signals comprising frequencies less than a threshold frequency; (iii) determining electrical energies of the low-frequency signals; (iv) determining a first energy by summing the electrical energies of the low-frequency signals; (v) consolidating the low-frequency signals into a consolidated low-frequency signal; (vi) determining a second energy by determining an electrical energy of the consolidated low-frequency signal; (vii) generating a gain-adjusted low-frequency signal by adjusting a gain of the consolidated low-frequency signal based on both (a) the first energy and (b) the second energy; (viii) generating a gain-adjusted multi-channel signal by mixing the gain-adjusted low-frequency signal back into the multi-channel signal; and (ix) using the gain-adjusted multi-channel signal to play back gain-adjusted multi-channel audio content via the playback device.

First claim

The invention claimed is:

1. A playback device comprising:
a plurality of audio drivers;
one or more processors;
tangible, non-transitory, computer-readable media storing instructions executable by the one or more processors to cause the playback device to perform operations comprising:
receiving a multi-channel audio signal representing multi-channel audio content for playback via the plurality of audio drivers, wherein respective channels of the multi-channel audio signal comprise respective low-frequency audio signals below a threshold frequency;
determining a first energy representing a sum of respective electrical energies of the respective low-frequency audio signals;
determining a second energy representing an electrical energy of a sum of the respective low-frequency audio signals; and
generating a gain-adjusted multi-channel audio signal by adjusting a gain of the low-frequency audio signals based on both (i) the first energy and (ii) the second energy.

2. The playback device of claim 1 , wherein determining the first energy comprises:
separating, from the respective channels of the multi-channel audio signal, the respective low-frequency audio signals;
determining the respective electrical energies of the respective low-frequency audio signals; and
summing the respective electrical energies of the respective low-frequency audio signals.

3. The playback device of claim 2 , wherein determining the second energy comprises:
consolidating the respective low-frequency audio signals into a consolidated low-frequency audio signal; and
determining an electrical energy of the consolidated low-frequency audio signal.

4. The playback device of claim 2 , wherein adjusting the gain of the low-frequency audio signals comprises individually adjusting the gain of each of the respective low-frequency audio signals, and wherein generating the gain-adjusted multi-channel audio signal comprises mixing the respective low-frequency audio signals into the respective channels of the multi-channel audio signal after individually adjusting the gain of each of the respective low-frequency audio signals.

5. The playback device of claim 3 , wherein adjusting the gain of the low-frequency audio signals comprises adjusting the gain of the consolidated low-frequency audio signal, and wherein generating the gain-adjusted multi-channel audio signal comprises mixing the consolidated low-frequency audio signal into the respective channels of the multi-channel audio signal after adjusting the gain of the consolidated low-frequency audio signal.

6. The playback device of claim 1 , wherein the multi-channel audio signal comprises a left-channel audio signal, a center-channel audio signal, and a right-channel audio signal, and wherein the respective low-frequency audio signals comprise:
a first low-frequency audio signal from the left-channel audio signal comprising first frequencies less than the threshold frequency;
a second low-frequency audio signal from the center-channel audio signal comprising second frequencies less than the threshold frequency; and
a third low-frequency audio signal from the right-channel audio signal comprising third frequencies less than the threshold frequency.

7. The playback device of claim 1 , wherein the multi-channel audio signal comprises a plurality of frames of audio content, wherein determining the first energy representing the sum of respective electrical energies of the respective low-frequency audio signals comprises determining, for an individual frame of the plurality of frames, the sum of respective electrical energies of the respective low-frequency audio signals, and wherein determining the second energy representing the electrical energy of the sum of the respective low-frequency audio signals comprises determining, for the individual frame of the plurality of frames, the electrical energy of the sum of the respective low-frequency audio signals.

8. The playback device of claim 1 , wherein the plurality of audio drivers includes a first audio driver and a second audio driver, and wherein a value of the threshold frequency is based on a distance between the first and second audio drivers.

9. The playback device of claim 8 , wherein the distance between the first and second audio drivers is an odd-integer multiple of a quarter-wavelength of the threshold frequency.

10. The playback device of claim 1 , wherein adjusting the gain of the low-frequency audio signals based on both (i) the first energy and (ii) the second energy comprises adjusting the gain of the low-frequency audio signals according to:
G=E 1 /E 2 ,
wherein G is the gain adjustment of the low-frequency audio signals, E 1 is the first energy, and E 2 is the second energy.

11. Tangible, non-transitory, computer-readable media storing instructions executable by one or more processors to cause a playback device to perform operations comprising:
receiving a multi-channel audio signal representing multi-channel audio content for playback via a plurality of audio drivers of the playback device, wherein respective channels of the multi-channel audio signal comprise respective low-frequency audio signals below a threshold frequency;
determining a first energy representing a sum of respective electrical energies of the respective low-frequency audio signals;
determining a second energy representing an electrical energy of a sum of the respective low-frequency audio signals; and
generating a gain-adjusted multi-channel audio signal by adjusting a gain of the low-frequency audio signals based on both (i) the first energy and (ii) the second energy.

12. The tangible, non-transitory, computer-readable media of claim 11 , wherein determining the first energy comprises:
separating, from the respective channels of the multi-channel audio signal, the respective low-frequency audio signals;
determining the respective electrical energies of the respective low-frequency audio signals; and
summing the respective electrical energies of the respective low-frequency audio signals.

13. The tangible, non-transitory, computer-readable media of claim 12 , wherein determining the second energy comprises:
consolidating the respective low-frequency audio signals into a consolidated low-frequency audio signal; and
determining an electrical energy of the consolidated low-frequency audio signal.

14. The tangible, non-transitory, computer-readable media of claim 11 , wherein adjusting the gain of the low-frequency audio signals comprises individually adjusting the gain of each of the respective low-frequency audio signals, and wherein generating the gain-adjusted multi-channel audio signal comprises mixing the respective low-frequency audio signals into the respective channels of the multi-channel audio signal after individually adjusting the gain of each of the respective low-frequency audio signals.

15. The tangible, non-transitory, computer-readable media of claim 13 , wherein adjusting the gain of the low-frequency audio signals comprises adjusting the gain of the consolidated low-frequency audio signal, and wherein generating the gain-adjusted multi-channel audio signal comprises mixing the consolidated low-frequency audio signal into the respective channels of the multi-channel audio signal after adjusting the gain of the consolidated low-frequency audio signal.

16. A method comprising:
receiving, by a playback device, a multi-channel audio signal representing multi-channel audio content for playback via a plurality of audio drivers of the playback device, wherein respective channels of the multi-channel aud

Assignees

• Sonos Inc

Inventors

• Lehnert Hilmar
• Ramos Aurelio
• Dizon Bob

Classifications

• H04S3/002

  Non-adaptive circuits, e.g. manually adjustable or static, for enhancing the sound image or the spatial distribution (control circuits for electronic adaptation of the sound field H04S7/30) · CPC title

• H04S2400/13

  Aspects of volume control, not necessarily automatic, in stereophonic sound systems · CPC title

• G10L21/0272

  Voice signal separating · CPC title

• H04R5/02

  Spatial or constructional arrangements of loudspeakers · CPC title

• H04S3/006

  in which a plurality of audio signals are transformed in a combination of audio signals and modulated signals, e.g. CD-4 systems · CPC title