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

Patent metadata

Field	Value
Publication number	US-10462599-B2
Application number	US-201815927981-A
Country	US
Kind code	B2
Filing date	Mar 21, 2018
Priority date	Mar 21, 2018
Publication date	Oct 29, 2019
Grant date	Oct 29, 2019

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

What is 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 playback device;
separating, from respective channels of the multi-channel audio signal, respective low-frequency audio signals comprising frequencies less than a threshold frequency;
determining respective electrical energies of each respective low-frequency audio signal;
determining a first energy by summing the respective electrical energies of each respective low-frequency audio signal;
consolidating the respective low-frequency audio signals into a consolidated low-frequency audio signal;
determining a second energy by determining an electrical energy of the consolidated low-frequency audio signal;
generating a gain-adjusted low-frequency audio signal by adjusting a gain of the consolidated low-frequency audio signal based on both (i) the first energy and (ii) the second energy;
generating a gain-adjusted multi-channel audio signal by mixing the gain-adjusted low-frequency audio signal back into the respective channels of the multi-channel audio signal; and
using the gain-adjusted multi-channel audio signal to play back gain-adjusted multi-channel audio content via the plurality of audio drivers.

2. 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 separating, from the respective channels of the multi-channel audio signal, the respective low-frequency audio signals that are below the threshold frequency comprises:
separating, from the left-channel audio signal, a first low-frequency audio signal comprising first frequencies less than the threshold frequency;
separating, from the center-channel audio signal, a second low-frequency audio signal comprising second frequencies less than the threshold frequency; and
separating, from the right-channel audio signal, a third low-frequency audio signal comprising third frequencies less than the threshold frequency.

3. The playback device of claim 2 , wherein the first low-frequency audio signal is different than the second and third low-frequency audio signals, and wherein the second low-frequency audio signal is different than the third low-frequency audio signal.

4. The playback device of claim 1 , wherein the multi-channel audio signal comprises a plurality of frames of audio content, wherein determining the respective electrical energies of each respective low-frequency audio signal comprises determining, for an individual frame of the plurality of frames, the respective electrical energies of each respective low-frequency audio signal, and wherein determining the electrical energy of the consolidated low-frequency audio signal comprises determining, for the individual frame of the plurality of frames, the electrical energy of the consolidated low-frequency audio signal.

5. 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.

6. The playback device of claim 5 , wherein the distance between the first and second audio drivers is an odd-integer multiple of a quarter-wavelength of the threshold frequency.

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

8. 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 the playback device;
separating, from respective channels of the multi-channel audio signal, respective low-frequency audio signals comprising frequencies less than a threshold frequency;
determining respective electrical energies of each respective low-frequency audio signal;
determining a first energy by summing the respective electrical energies of each respective low-frequency audio signal;
consolidating the respective low-frequency audio signals into a consolidated low-frequency audio signal;
determining a second energy by determining an electrical energy of the consolidated low-frequency audio signal;
generating a gain-adjusted low-frequency audio signal by adjusting a gain of the consolidated low-frequency audio signal based on both (i) the first energy and (ii) the second energy;
generating a gain-adjusted multi-channel audio signal by mixing the gain-adjusted low-frequency audio signal back into the respective channels of the multi-channel audio signal; and
using the gain-adjusted multi-channel audio signal to play back gain-adjusted multi-channel audio content via a plurality of audio drivers of the playback device.

9. The tangible, non-transitory, computer-readable media of claim 8 , 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 separating, from the respective channels of the multi-channel audio signal, the respective low-frequency audio signals that are below the threshold frequency comprises:
separating, from the left-channel audio signal, a first low-frequency audio signal comprising first frequencies less than the threshold frequency;
separating, from the center-channel audio signal, a second low-frequency audio signal comprising second frequencies less than the threshold frequency; and
separating, from the right-channel audio signal, a third low-frequency audio signal comprising third frequencies less than the threshold frequency.

10. The tangible, non-transitory, computer-readable media of claim 9 , wherein the first low-frequency audio signal is different than the second and third low-frequency audio signals, and wherein the second low-frequency audio signal is different than the third low-frequency audio signal.

11. The tangible, non-transitory, computer-readable media of claim 8 , wherein the multi-channel audio signal comprises a plurality of frames of audio content, wherein determining the respective electrical energies of each respective low-frequency audio signal comprises determining, for an individual frame of the plurality of frames, the respective electrical energies of each respective low-frequency audio signal, and wherein determining the electrical energy of the consolidated low-frequency audio signal comprises determining, for the individual frame of the plurality of frames, the electrical energy of the consolidated low-frequency audio signal.

12. The tangible, non-transitory, computer-readable media of claim 8 , 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.

13. The tangible, non-transitory, computer-readable media of claim 12 , wherein the distance between the first and second audio drivers is an odd-int

Assignees

• Sonos Inc

Inventors

• Lehnert Hilmar
• Ramos Aurelio
• Dizon Bob

Classifications

• H04S7/307 Primary

  Frequency adjustment, e.g. tone control (H04S7/301 takes precedence) · CPC title

• 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

• H04S2400/07

  Generation or adaptation of the Low Frequency Effect [LFE] channel, e.g. distribution or signal processing · CPC title

• G10L21/0272

  Voice signal separating · CPC title