Multi-channel audio enhancement system

• US 8,509,464 B1
• Filed: 10/31/2011
• Issued: 08/13/2013
• Est. Priority Date: 12/21/2006
• Status: Active Grant

• Current Assignee: DTS, Inc. (Adeia Inc.)
• Original Assignee: DTS, Inc. (Adeia Inc.)
• Inventors: Kato, Hideaki, Kraemer, Alan, Yang, Sarah
• Primary Examiner(s): FLETCHER, MARLON T
• Application Number:
  US13/286,082
• Time in Patent Office: 652 Days
• Field of Search: None
• 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 applying at least one front perspective filter to each of 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 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 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 one or more definition filters to the filtered left and right front output signals to enhance the left and right front input signals, the one or more definition filters comprising a high-pass shelving filter configured to produce left and right front output signals;

providing the left and right front output signals to first front speakers;

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; and

applying the left and right rear output signals to second front speakers, wherein the left and right rear output signals are each configured to drive one of the second front speakers to simulate a rear surround sound effect.

2. The method of claim 1, further comprising enhancing dialog of at least one of (a) the left and right front audio signals and (b) a center front audio signal.

3. The method of claim 1, further comprising enhancing a bass response associated with at least the filtered left and right front output signals.

4. The method of claim 1, wherein the at least one rear perspective filter comprises a combination of a high pass filter, a first low pass filter, and a second low pass filter.

5. The method of claim 4, wherein the high pass filter has a corner frequency of about 13 kHz.

6. The method of claim 4, wherein the first low pass filter has a corner frequency of about 950 Hz.

7. The method of claim 4, wherein the second low pass filter has a corner frequency of about 8 kHz.

8. The method of claim 1, 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.

9. The method of claim 1, wherein the method is implemented by one or more processors.

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

a definition module configured to;

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

apply one or more definition filters comprising a high-pass shelving filter to the left and right front input signals to enhance the left and right front input signals and thereby produce left and right front output signals, and

output the left and right front output signals for playback by first front speakers; and

at least one rear perspective filter configured to;

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

filter each of the left and right rear audio signals to yield left and right rear output signals, and

output the left and right rear output signals for playback by second front speakers, wherein the left and right rear output signals are each configured to drive one of the second front speakers to simulate a rear surround sound effect.

11. The system of claim 10, 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.

12. The system of claim 10, 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.

13. The system of claim 10, further comprising a 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.

14. The system of claim 10, wherein the at least one rear perspective filter comprises a combination of a high pass filter, a first low pass filter, and a second low pass filter.

15. The system of claim 14, wherein the high pass filter has a corner frequency of about 13 kHz.

16. The system of claim 14, wherein the first low pass filter has a corner frequency of about 950 Hz.

17. The system of claim 14, wherein the second low pass filter has a corner frequency of about 8 kHz.

18. The system of claim 10, wherein one or both of the definition module and the at least one rear perspective filter are implemented by one or more processors.