Multi-channel audio enhancement system

• US 8,050,434 B1
• Filed: 12/21/2007
• Issued: 11/01/2011
• Est. Priority Date: 12/21/2006
• Status: Active Grant

• Current Assignee: DTS, Inc. (Adeia Inc.)
• Original Assignee: SRS Labs Incorporated (Adeia Inc.)
• Inventors: Kato, Hideaki, Kraemer, Alan, Yang, Sarah
• Primary Examiner(s): LOCKETT, KIMBERLY R
• Application Number:
  US11/963,679
• Time in Patent Office: 1,411 Days
• Field of Search: 381/300, 381/310, 381/311, 381 61- 65, 381/58, 381/59
• US Class Current: 381/310
• CPC Class Codes: H04R 5/00 Stereophonic arrangements stereophonic pick-ups H04R9/16, H04R11/12, H04R17/08, H04R19/10
• CPC Class Codes: H04S 2400/03 Aspects of down-mixing multi-channel audio to configurations with lower numbers of playback channels, e.g. 7.1 -> 5.1 H04S2400/01 takes precedence
• CPC Class Codes: H04S 2400/05 Generation or adaptation of centre channel in multi-channel audio systems
• CPC Class Codes: H04S 2400/07 Generation or adaptation of the Low Frequency Effect [LFE] channel, e.g. distribution or signal processing
• CPC Class Codes: H04S 2420/01 Enhancing the perception of the sound image or of the spatial distribution using head related transfer functions [HRTF's] or equivalents thereof, e.g. interaural time difference [ITD] or interaural level difference [ILD]
• CPC Class Codes: H04S 3/002 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 Class Codes: H04S 7/308 Electronic adaptation dependent on speaker or headphone connection

Abstract

A method for processing audio signals can include receiving left and right front audio signals, where the left and right front audio signals including information about front spatial position of sound sources relative to a listener. The method can also include receiving left and right rear audio signals, where the left and right rear audio signals include information about rear spatial position of sound sources relative to a listener. In addition, the method can include applying at least one front perspective filter to each of the left and right front audio signals to yield filtered left and right front output signals, where the left and right front output signals each drive a front speaker. Moreover, the method can include applying at least one rear perspective filter to each of the left and right rear audio signals to yield left and right rear output signals, where the left and right rear output signals each drive a rear speaker to simulate a rear surround sound effect when positioned in front of a listener.

Claims

1. A system for processing audio signals, the system comprising:

left and right front audio signals each comprising information about a front spatial position of a sound source relative to a listener;

left and right rear audio signals each comprising information about a rear spatial position of a sound source relative to a listener;

a dialog clarity module configured to enhance dialog in at least one of (a) the left and right front audio signals and (b) a center front audio signal;

at least one front perspective filter configured to filter each of the left and right front audio signals to yield filtered left and right front output signals, wherein the left and right front output signals are each configured to drive a front speaker;

at least one rear perspective filter configured to filter each of the left and right rear audio signals to yield left and right rear output signals, wherein the left and right rear output signals are each configured to drive a rear speaker to simulate a rear surround sound effect when positioned facing a listener; and

a bass management module configured to;

enhance a bass response associated with at least the filtered left and right front output signals; and

selectively apply crossover filters to one or more of the filtered left and right front output signals and the filtered left and right rear output signals.

2. The system of claim 1, wherein the at least one rear perspective filter comprises a combination of a high pass filter having a corner frequency of about 13 kilohertz (kHz), a low pass filter having a corner frequency of about 950 hertz (Hz), and a low pass filter having a corner frequency of about 8 kHz.

3. The system of claim 1, wherein the bass management module is further configured to enhance a subwoofer audio signal.

4. The system of claim 1, wherein the dialog clarity module is configured to enhance dialog in at least one of (a) the left and right front audio signals and (b) a center front audio signal by emphasizing formants in a high frequency range of speech.

5. The system of claim 1, wherein the crossover filters comprise a low pass filter configured to filter a subwoofer audio signal.

6. The system of claim 1, wherein the crossover filters comprise at least one high pass filter configured to filter the filtered left and right front output signals.

7. The system of claim 1, further comprising a definition module comprising one or more definition filters configured to process the filtered left and right front output signals to enhance the filtered left and right front output signals.

9. The method of claim 7, wherein the at least one rear perspective filter comprises a combination of a high pass filter having a corner frequency of about 13 kilohertz (kHz), a low pass filter having a corner frequency of about 950 hertz (Hz), and a low pass filter having a corner frequency of about 8 kHz.

10. The method of claim 7, further comprising enhancing dialog of at least one of (a) the left and right front audio signals and (b) a center front audio signal.

11. The method of claim 7, further comprising enhancing a bass response associated with at least the filtered left and right front output signals.

12. The method of claim 7, further comprising processing at least a portion of the filtered left and right front output signals and the filtered left and right rear output signals with a crossover network.

13. The method of claim 7, further comprising using a definition module comprising one or more definition filters to process the filtered left and right front output signals to enhance the filtered left and right front output signals.

8. A method for processing audio signals, the method comprising:

receiving left and right front audio signals, the left and right front audio signals each comprising information about a front spatial position of a sound source relative to a listener;

receiving left and right rear audio signals, the left and right rear audio signals each comprising information about a rear spatial position of a sound source relative to a listener;

applying at least one front perspective filter to each of the left and right front audio signals to yield filtered left and right front output signals, wherein the left and right front output signals are each configured to drive a front speaker; and

applying at least one rear perspective filter to each of the left and right rear audio signals to yield left and right rear output signals, wherein the left and right rear output signals are each configured to drive a rear speaker to simulate a rear surround sound effect when positioned in front of a listener.

14. A system for processing audio signals, the system comprising:

left and right front audio signals each comprising information about a front spatial position of a sound source relative to a listener;

left and right rear audio signals each comprising information about a rear spatial position of a sound source relative to a listener;

at least one front perspective filter configured to filter each of the left and right front audio signals to yield filtered left and right front output signals, wherein the left and right front output signals are each configured to drive a front speaker; and

at least one rear perspective filter configured to filter each of the left and right rear audio signals to yield left and right rear output signals, wherein the left and right rear output signals are each configured to drive a rear speaker to simulate a rear surround sound effect when positioned facing a listener.

15. The system of claim 14, wherein the at least one rear perspective filter comprises a combination of a high pass filter having a corner frequency of about 13 kilohertz (kHz), a low pass filter having a corner frequency of about 950 hertz (Hz), and a low pass filter having a corner frequency of about 8 kHz.

16. The system of claim 14, further comprising a dialog clarity module configured to enhance dialog in at least one of (a) the left and right front audio signals and (b) a center front audio signal.

17. The system of claim 14, further comprising a bass management module configured to enhance a bass response associated with one or more of the filtered left and right front output signals and a subwoofer audio signal.

18. The system of claim 14, wherein the dialog clarity module is configured to enhance dialog in at least one of (a) the left and right front audio signals and (b) a center front audio signal by emphasizing formants in a high frequency range of speech.

19. The system of claim 14, further comprising a definition module comprising one or more definition filters configured to process the filtered left and right front output signals to enhance the filtered left and right front output signals.