System and method for directionally radiating sound

Patent metadata

Field	Value
Publication number	US-9100748-B2
Application number	US-78046107-A
Country	US
Kind code	B2
Filing date	Jul 19, 2007
Priority date	May 4, 2007
Publication date	Aug 4, 2015
Grant date	Aug 4, 2015

Abstract

A method of operating an audio system that provides audio radiation to a plurality of listening positions includes providing at least one source of audio signals. At each listening position, at least one array of speaker elements is provided. A filter is provided between the at least one source and at least one of the speaker elements at a first listening position. The filter is optimized so that the filter reduces acoustic energy radiated from the first array to at least one other listening position of the plurality of listening positions, compared to acoustic energy radiated from the first array to the first listening position.

First claim

What is claimed is:

1. A method of providing and operating an audio system that provides audio radiation to a plurality of listening positions located in an environment, the method comprising the steps of:
(a) providing at least one source of audio signals;
(b) providing, at each of a plurality of the listening positions in the environment, at least one array of speaker elements that receives the audio signals and responsively radiates output acoustic energy, wherein the speaker elements of each array are disposed with respect to each other so that the output acoustic energy radiated from respective said speaker elements destructively interfere to thereby define a directional audio radiation from the at least one array;
(c) providing a filter between the at least one source and at least one of the speaker elements in a first said array at a first listening position of the plurality of listening positions, wherein the filter processes the audio signals from the at least one source to the at least one speaker element;
(d) defining a cost function that compares acoustic energy in the environment radiated from the first array to at least one other listening position of the plurality of listening positions to acoustic energy in the environment radiated from the first array to the first listening position;
(e) calculating the cost function; and
(f) iteratively modifying the filter in response to the calculated cost function toward a predetermined criteria so that the filter reduces a magnitude of acoustic energy radiated from the first array to the at least one other listening position, compared to a magnitude of acoustic energy radiated from the first array to the first listening position.

2. The method as in claim 1 , including providing a said first array at each listening position of the plurality of listening positions.

3. The method as in claim 2 , including providing a plurality of said first arrays at each listening position of the plurality of listening positions.

4. The method as in claim 1 , wherein the first array is comprised of a first said speaker element and at least one second said speaker element, and wherein step (c) includes providing a said filter between the at least one source and each said second speaker element.

5. The method as in claim 1 , wherein the cost function compares acoustic energy radiated from the first array to an acoustically reflective surface near the first listening position to acoustic energy radiated from the first array to the first listening position, so that the filter reduces a magnitude of acoustic energy radiated from the first array to the acoustically reflective surface, compared to a magnitude of acoustic energy radiated from the first array to the first listening position.

6. The method of claim 1 , wherein the plurality of listening positions are in a vehicle, wherein each listening position is a seat position in the vehicle, and step (a) comprises providing the at least one source of audio signals in the vehicle.

7. The method as in claim 1 , comprising the steps of:
providing a plurality of microphones respectively mounted at the plurality of listening positions so that each microphone detects speech from an occupant of the listening position at which it is mounted and outputs signals corresponding to the detected speech; and
in response to a said microphone detecting speech at its listening position, driving a respective loudspeaker array at each other listening position of the plurality of listening positions to radiate acoustic energy corresponding to the detected speech, wherein the driving step comprises processing signals that drive the respective loudspeaker arrays at the other listening positions and that correspond to the detected speech so that each respective loudspeaker array at each said other listening position directionally radiates first acoustic energy to its listening position and directionally radiates second acoustic energy to the microphone's listening position and so that the second acoustic energy is less than the first acoustic energy according to a predetermined criteria.

8. The method as in claim 1 , wherein the cost function compares a transfer function between the at least one source to the at least one other listening position to a transfer function between the at least one source and the first listening position.

9. A method of providing and operating an audio system that provides audio radiation to listening positions, the method comprising the steps of:
(a) providing at least one source of audio signals;
(b) providing, at each of a plurality of the listening positions, at least one array of speaker elements that receives the audio signals and responsively radiates output acoustic energy, wherein the speaker elements of the at least one array are disposed with respect to each other so that the output acoustic energy radiated from respective said speaker elements destructively interfere to thereby define a directional audio radiation from the at least one array;
(c) providing a filter between the at least one source and at least one of the speaker elements in a first said array at a first listening position of the plurality of listening positions, wherein the filter processes the audio signals from the at least one source to the at least one speaker element; and
(d) optimizing the filter, based on a comparison of acoustic energy radiated from the first array to at least one other listening position of the plurality of listening positions to acoustic energy radiated from the first array to the first listening position, so that the filter reduces a magnitude of acoustic energy radiated from the first to the at least one other listening position, compared to a magnitude of acoustic energy radiated from the first array to the first listening position,
wherein step (d) comprises the steps of
(d1) driving each of the speaker elements in the first array to radiate first said output acoustic energy,
(d2) detecting the first output acoustic energy at the first listening position and at the at least one other listening position,
(d3) determining a first transfer function between the first output acoustic energy detected at the first listening position and the audio signals from the at least one source,
(d4) determining a second transfer function between the first output acoustic energy detected at the at least one other listening position and the audio signals from the at least one source,
(d5) computing a cost function that compares the first transfer function and the second transfer function,
(d6) determining a gradient of the cost function that defines a direction toward reduction of the cost function,
(d7) modifying respective portions of the first transfer function and the second transfer function that correspond to the filter according to the direction, and
(d8) repeating steps (d5) to (d7) until the result of step (d5) meets a predetermined criteria.

10. A method of providing and operating an audio system that provides audio radiation to listening positions, the method comprising the steps of:
(a) providing at least one source of audio signals;
(b) providing, at each of a plurality of the listening positions, at least one array of speaker elements that receives the audio signals and responsively radiates output acoustic energy, wherein the speaker elements of the at least one array are disposed with respect to each other so that the output acoustic energy radiated from respective said speaker elements destructively interfere to thereby define a directional audio radiation from the at least one array;
(c) providing a filter between the at least one source and at least one of the speaker elements in a first said array at a firs

Assignees

• Hartung Klaus
• Hultz Paul B
• Bose Corp

Inventors

• Hartung Klaus
• Hultz Paul B

Classifications

• H04S7/30

  Control circuits for electronic adaptation of the sound field · CPC title

• H04R3/12 Primary

  for distributing signals to two or more loudspeakers {(specially adapted for hearing aids H04R25/407)} · CPC title

• H04R1/403

  loud-speakers · CPC title

• H04R2499/13

  Acoustic transducers and sound field adaptation in vehicles · CPC title

• H04R2205/022

  Plurality of transducers corresponding to a plurality of sound channels in each earpiece of headphones or in a single enclosure · CPC title