Method for loudness calibration of a multichannel sound systems and a multichannel sound system

• US 6,639,989 B1
• Filed: 09/22/1999
• Issued: 10/28/2003
• Est. Priority Date: 09/25/1998
• Status: Expired due to Term

• Current Assignee: Nokia Technologies Oy (Nokia Corporation)
• Original Assignee: Nokia Display Products Incorporated (Nokia Corporation)
• Inventors: Zacharov, Nick, Suokuisma, Pekka
• Primary Examiner(s): Isen, Forester W.
• Assistant Examiner(s): PENDLETON, BRIAN T
• Application Number:
  US09/400,770
• Time in Patent Office: 1,497 Days
• Field of Search: 381/59, 381/96, 381/103, 381/58, 381/98, 381/56, 381/104, 381/107, 381/99, 381/101, 381/102, 381/303, 381/307
• US Class Current: 381/303
• CPC Class Codes: H04S 7/301 Automatic calibration of stereophonic sound system, e.g. with test microphone
• CPC Class Codes: H04S 7/302 Electronic adaptation of stereophonic sound system to listener position or orientation H04S7/301 takes precedence

Abstract

A method and a system for loudness calibration of a multichannel sound systems, wherein the test signal is psychoacoustically shaped. The psychoacoustically shaped test signal is preferably a pseudorandom test signal suitable for both automatic and subjective loudness calibration. Further, the psychoacoustically shaped test signal preferably has essentially constant specific loudness on the frequency range essential for aural perception.

Claims

1. A method for loudness calibration of a multichannel sound system having at least two sound sources each for providing a different channel of the multichannel sound system, comprising steps of

a) generating a test signal for each of the two sound sources,

b) transmitting the test signals from the two sound sources,

c) receiving the test signals at a listening position,

d) calibrating loudness using the received test signals, wherein in the step of generating the test signals, psychoacoustically shaped test signals are generated, and wherein the test signals each have an essentially constant specific loudness on at least substantially the whole frequency range necessary for audio perception.

2. The method according to claim 1, wherein said test signals are pseudorandom signals.

3. The method according to claim 2, wherein at least one of said test signals is a Maximum-Length Sequence (MLS) type signal.

4. The method according to claim 1, wherein the step of generating the psychoacoustically shaped test signals comprises generating individual psychoacoustically shaped test signals for each of the two sound sources.

5. The method according to claim 4, wherein said test signals are generated for different sound sources according to the location of the sound source with respect to the listening location.

6. The method according to claim 1, wherein the step of generating the psychoacoustically shaped test signals comprises generating individual psychoacoustically shaped test signals for each person carrying out the calibration of the system.

7. The method according to claim 1, wherein the step of calibrating loudness comprises carrying out both automatic loudness calibration and manual loudness calibration using the same psychoacoustically shaped test signals.

8. A multichannel sound system comprising:

at least two sound sources, each for providing a different channel of the multichannel sound system,

means for generating a test signal for each of the two sound sources of the multichannel sound system, and

means for carrying out loudness calibration according to the test signals transmitted by each of the two sound sources, wherein the means for generating the test signals generates a psychoacoustically shaped test signal.

9. The system according to claim 8, the means for generating a test signal generates a psychoacoustically shaped test signal for automatic loudness calibration.

10. The system according to claim 8, wherein the means for generating a test signal generates a pseudorandom psychoacoustically shaped test signal.

11. The system according to claim 10, wherein the means for generating a test signal generates a Maximum-Length sequence (MLS) type signal.

12. The system according to claim 8, wherein the means for generating a test signal comprises means for generating individually shaped test signals for different sound sources.

13. The system according to claim 12, wherein the means for generating a test signal comprises means for shaping individual test signals for different sound sources according to the location of the sound source in respect to the listening location.

14. The system according to claim 10, wherein the means for generating a test signal generates an individual psychoacoustically shaped test signal for each person calibrating the system.

15. The system according to claim 8, wherein the means for carrying out loudness calibration comprises means for carrying out manual loudness calibration.

16. A method for loudness calibration of a multichannel sound system, comprising steps of

a) generating a test signal,

b) transmitting the test signal from at least one sound source,

c) receiving the test signal preferably at the presumed listening position,

d) calibrating loudness using the received test signal, wherein in the step of generating a test signal, a psychoacoustically shaped test signal is generated, and wherein the test signal has an essentially constant specific loudness on at least substantially the whole frequency range necessary for audio perception, and wherein the test signal is a pseudorandom Maximum-Length Sequence (MLS) type signal.

17. A multichannel sound system having at least

means for generating a test signal,

at least two sound sources, and

means for carrying out loudness calibration according to the test signal transmitted by at least one sound source, wherein the means for generating a test signal generates a pseudorandom psychoacoustically shaped test signal, wherein the means for generating a test signal generates a pseudorandom psychoacoustically shaped Maximum-Length Sequence (MLS) type test signal.