Electrical system for a speaker and its control

• US 8,588,431 B2
• Filed: 04/20/2009
• Issued: 11/19/2013
• Est. Priority Date: 04/21/2008
• Status: Active Grant

• Current Assignee: Caavo Inc
• Original Assignee: SNAP Networks, Inc.
• Inventors: Aggarwal, Ashish Dharmpal, Kasibhat, Subramanyam
• Primary Examiner(s): Mei, Xu
• Application Number:
  US12/988,486
• Publication Number:
  US 20110064258A1
• Time in Patent Office: 1,674 Days
• Field of Search: 381/58, 381/59, 381/95, 381/96, 381/309, 381/310, 381/91, 381/92, 381/122, 381/61
• US Class Current: 381/58
• CPC Class Codes: F21V 33/0056 Audio equipment, e.g. music instruments, radios or speakers
• CPC Class Codes: H04R 1/02 Casings; Cabinets ; Supports therefor; Mountings therein H04R1/28 takes precedence ; attachments for microphones H04R1/08; mounting of transducers in earpieces H04R1/1075
• CPC Class Codes: H04R 1/028 associated with devices performing functions other than acoustics, e.g. electric candles
• 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

An electrical apparatus includes a frame, a speaker connected to the frame, a digital signal processor in communication with the speaker to receive audio data and control data to control the speaker, the digital signal processor connected to the frame, and a lamp base coupler electrically connected to the speaker and receiver, the lamp base coupler detachably connectable to a power source, when the power source is present. A method of steering the diffused sound field includes, broadcasting at least one calibration audio signal through a plurality of speakers (M) in an audio system, receiving the calibration audio signal in a plurality of microphones spaced apart and positioned about at a listening position, and calculating respective relative speaker placement angles relative to the listening position between each of the plurality of speakers in response to receipt of the calibration audio signal in the plurality of microphones.

Claims

1. A method of simulating an ideal virtual channel position in an audio system, said method comprising:

broadcasting at least one calibration audio signal through each of a plurality of speakers (M) in said audio system;

receiving the calibration audio signal in a plurality of microphones spaced apart and positioned at a predetermined listening position;

calculating a speaker placement angle relative to said predetermined listening position, wherein said angle is determined using an impulse response to said calibration audio signal, and wherein said angle is calculated between each of said plurality of speakers (M) and said plurality of microphones;

determining a multi-planar angular location for each of said plurality of speakers (M) in relation to said listening position to facilitate a simulation of an ideal virtual channel position;

rotating a sound field using at least a parameter obtained from a calculation of the angular location relative to said listening position; and

amplifying at least a virtual output audio channel amplitude vector through said plurality of speakers (M) thereby rotating said sound field.

2. The method of claim 1, further comprising:

receiving at least a digital audio sample comprising a plurality of input digital audio signal channels (N) to generate at least an input audio channel amplitude vector representing said sound field;

determining said ideal virtual channel position relative to said listening position for each of said plurality of input digital audio signal channels (N);

rotating said sound field to generate the virtual output audio channel amplitude vector to simulate said ideal virtual channel position relative to said listening position; and

amplifying said virtual output audio channel amplitude vector through said plurality of speakers (M).

3. The method of claim 2, wherein the rotating of said sound field comprises:

mapping said input digital audio signal channels (N) to said plurality of speakers (M); and

multiplying said input audio channel amplitude vector by the mapping to generate said virtual output speaker channel amplitude vector.

4. The method of claim 3, wherein the mapping of said input digital audio signal channels (N) comprises:

calculating, for each of said ideal virtual channel position, at least a nearest pair of speakers (s1, s2) on opposing sides of said ideal virtual channel position and selected from said plurality of speakers (M);

calculating, relative to said listening position, relative angular differences (Ia1, Ia2) between each of the nearest pair of speakers (s1, s2) and their ideal virtual channel positions;

calculating rotational matrix coefficients g1 and g2 according to;

sqrt(g1*g1+g2*g2)=1;

g1/g2=cos(Ia1 )/cos(Ia2); and

populating at least an M×

N rotational matrix with said coefficients g1 and g2 at cells MiN1 and M2Ni, respectively.

5. The method of claim 2, wherein the broadcasting of at least one calibration audio signal is performed sequentially through each of said plurality of speakers (M).

6. The method of claim 2, wherein said calibration audio signal comprises a frequency sweep.

7. The method of claim 2, wherein said plurality of input digital audio signals (N) are rotated for amplification through said plurality of speakers (M) for broadcast in said audio system that simulates said ideal virtual channel positions relative to said listening position.

8. A method of simulating an ideal virtual channel position in an audio system, said method comprising:

broadcasting at least one calibration audio signal through each of a plurality of speakers (M) in said audio system;

receiving the calibration audio signal in a plurality of microphones spaced apart and positioned at a predetermined listening position;

calculating a speaker placement angle relative to said predetermined listening position, wherein said angle is determined using an impulse response to said calibration audio signal, and wherein said angle is calculated between each of said plurality of speakers (M) and said plurality of microphones;

determining a multi-planar angular location for each of said plurality of speakers (M) in relation to said listening position to facilitate a simulation of an ideal virtual channel position;

rotating a sound field using at least a parameter obtained from a calculation of the angular location relative to said listening position;

amplifying at least a virtual output audio channel amplitude vector through said plurality of speakers (M) thereby rotating said sound field;

receiving at least a digital audio sample comprising a plurality of input digital audio signal channels (N) to generate at least an input audio channel amplitude vector representing said sound field;

determining said ideal virtual channel position relative to said listening position for each of said plurality of input digital audio signal channels (N);

rotating said sound field to generate the virtual output audio channel amplitude vector to simulate said ideal virtual channel position relative to said listening position; and

amplifying said virtual output audio channel amplitude vector through said plurality of speakers (M).

9. The method of claim 8, wherein the rotating of said sound field comprises:

mapping said input digital audio signal channels (N) to said plurality of speakers (M); and

multiplying said input audio channel amplitude vector by the mapping to generate said virtual output speaker channel amplitude vector.

10. The method of claim 9, wherein the mapping of said input digital audio signal channels (N) comprises:

calculating, for each of said ideal virtual channel position, at least a nearest pair of speakers (s1, s2) on opposing sides of said ideal virtual channel position and selected from said plurality of speakers (M);

calculating, relative to said listening position, relative angular differences (Ia1, Ia2) between each of the nearest pair of speakers (s1, s2) and their ideal virtual channel positions;

calculating rotational matrix coefficients g1 and g2 according to;

sqrt(g1*g1+g2*g2)=1;

g1/g2=cos(Ia1)/cos(Ia2); and

populating at least an M×

N rotational matrix with said coefficients g1 and g2 at cells MiN1 and M2Ni, respectively.

11. The method of claim 8, wherein the broadcasting of at least one calibration audio signal is performed sequentially through each of said plurality of speakers (M).

12. The method of claim 8, wherein said calibration audio signal comprises a frequency sweep.

13. The method of claim 8, wherein said plurality of input digital audio signals (N) are rotated for amplification through said plurality of speakers (M) for broadcast in said audio system that simulates said ideal virtual channel positions relative to said listening position.