Method and system for adapting a loudspeaker to a listening position in a room

• US 8,144,883 B2
• Filed: 04/27/2005
• Issued: 03/27/2012
• Est. Priority Date: 05/06/2004
• Status: Active Grant

• Current Assignee: Bang & Olufsen a/s
• Original Assignee: Bang & Olufsen a/s
• Inventors: Pedersen, Jan Abildgaard
• Primary Examiner(s): Faulk, Devona
• Assistant Examiner(s): Paul, Disler
• Application Number:
  US11/568,721
• Publication Number:
  US 20080008329A1
• Time in Patent Office: 2,526 Days
• Field of Search: 381/56, 381/96, 381/103, 381/303, 381 58- 59
• US Class Current: 381/59
• CPC Class Codes: H04R 2205/024 Positioning of loudspeaker enclosures for spatial sound reproduction
• CPC Class Codes: H04R 29/001 for loudspeakers H04R29/007 takes precedence
• CPC Class Codes: H04R 3/04 for correcting frequency response
• CPC Class Codes: H04S 7/302 Electronic adaptation of stereophonic sound system to listener position or orientation H04S7/301 takes precedence

Abstract

The invention relates to a method and a system for adapting a loudspeaker to a specific listening position relative to the loudspeaker according to which method and system the acoustic power radiated by the loudspeaker is corrected by means of a correction filter inserted in the signal path through the loudspeaker, the response of said correction filter being determined by comparison between the a quantity characterising the radiated acoustic power measured at an actual listening position and a similar quantity measured at a reference listening position. According to a specific embodiment of the invention said characterising quantities are the radiation resistances measured at the actual listening position and the reference listening position respectively.

Claims

1. A method for adapting a loudspeaker to a specific listening position relative to the loudspeaker by correcting acoustic power radiated by the loudspeaker by means of a correction filter inserted in the signal path through the loudspeaker, the method comprising:

(i) measuring, at an actual listening position, a first quantity characterising the acoustic power radiated by the loudspeaker;

(ii) measuring, at a reference listening position, a second quantity characterising the acoustic power radiated by the loudspeaker;

(iii) using an electronic comparison means to determine a response of a correction filter by a comparison between said first quantity and said second quantity;

(iv) implementing said correction filter; and

(v) inserting said correction filter in the signal path through the loudspeaker, and

wherein said first and second characterising quantities are radiation resistances measured at the actual listening position and the reference listening position, respectively.

2. The method according to claim 1 where the frequency response of said correction filter is given by

3. The method according to claim 2 comprising a further adaptation of the loudspeaker to the actual position in the listening room in which the loudspeaker is placed by means of a correction filter, the frequency response (Amp(f)) of which is given by

4. The method according to claim 3, where the radiation resistances at the actual listening position and reference listening position are measured by means of the loudspeaker adapted to the actual position in the listening room.

5. The method according to claim 3, where the radiation resistances at the actual listening position and reference listening position are measured by a dedicated sound source.

6. The method according to claim 1, wherein the radiation resistances measured at said reference loudspeaker and measured at the listening positions are replaced by predetermined radiation resistances.

7. The method according to claim 6, where said predetermined radiation resistances are the free field radiation resistances being a function of f².

8. A system for adapting a loudspeaker to a specific listening position in a room relative to the loudspeaker by correcting acoustic power radiated by the loudspeaker by means of a correction filter inserted in the signal path through the loudspeaker, said system comprising

a processing unit means that determines a response of a correction filter by a comparison between said a first quantity measured at an actual listening position that characterizes the acoustic power radiated by the loudspeaker and a second quantity measured at a reference listening position that characterizes the acoustic power radiated by the loudspeaker;

and

filter means for implementing said correction filter based on transfer functions LS(f) and LISTENER(f),

where

9. A system according to claim 8, said system furthermore comprising means for storing either predetermined radiation resistances or measured radiation resistances.

10. A system according to claim 8 furthermore comprising a dedicated sound source for carrying out measurements of radiation resistance at the actual listening position and at the reference listening position.