Apparatus and method for driving an array of loudspeakers

Patent metadata

Field	Value
Publication number	US-10284993-B2
Application number	US-201715722637-A
Country	US
Kind code	B2
Filing date	Oct 2, 2017
Priority date	Apr 8, 2015
Publication date	May 7, 2019
Grant date	May 7, 2019

Abstract

A local wave field synthesis apparatus, which includes a determination module for determining desired sound pressures and desired particle velocity vectors at a plurality of control points, a computation module for computing sound pressures and particle velocity vectors at the plurality of control points based on a set of filter parameters, an optimization module for computing an optimum set of filter parameters by jointly optimizing computed sound pressures towards the desired sound pressures and computed particle velocity vectors towards the desired particle velocity vectors, and a generator module for generating the drive signals based on the optimum set of filter parameters, wherein the plurality of control points are located on one or more contours around the one or more audio zones.

First claim

What is claimed is:

1. A local wave field synthesis apparatus for driving an array of loudspeakers with drive signals to generate one or more local wave fields at one or more audio zones, the apparatus comprising:
a memory storing program codes; and
a processor configured to execute the program codes to cause the apparatus to:
determine desired sound pressures and desired particle velocity vectors at a plurality of control points, wherein the plurality of control points are located on one or more contours around the one or more audio zones,
compute sound pressures and particle velocity vectors at the plurality of control points based on a set of filter parameters,
compute an optimum set of filter parameters by jointly optimizing the computed sound pressures towards the desired sound pressures and the computed particle velocity vectors towards the desired particle velocity vectors, wherein computing the optimum set of filter parameters is based on optimizing a cost function:

min

w
⁡

(
ω
)

⁢

{

κ
⁢



H
⁡

(
ω
)

⁢

w
⁡

(
ω
)

-

g
des

⁡

(
ω
)



2
2

+

(

1
-
κ

)

⁢



𝒟
⁡

(
ω
)

⁢

H
⁡

(
ω
)

⁢

w
⁡

(
ω
)

-

v
des

⁡

(
ω
)



2
2

}

,

wherein w is a vector comprising the set of filter parameters, ω is a frequency, κ is a relative weight with 0≤κ≤1, H is a matrix comprising transfer functions from the loudspeakers to the control points, g des is a vector indicating the desired sound pressures, v des is a vector indicating the desired particle velocity vectors, and is a difference matrix; and
generate the drive signals based on the optimum set of filter parameters.

2. The apparatus of claim 1 , wherein determining the desired sound pressures is based on a virtual position of a virtual sound source.

3. The apparatus of claim 1 , wherein determining the desired particle velocity vectors is based on computing differences between sound pressures at different control points of the plurality of control points.

4. The apparatus of claim 1 , wherein computing the optimum set of filter parameters comprises computing the optimum set of filter parameters separately for different frequencies.

5. The apparatus of claim 1 , wherein the control points are arranged on the one or more contours in multiple L-shaped groups.

6. The apparatus of claim 1 , wherein the processor is further configured to receive input signals from one or more microphones, and compute the sound pressures and the particle velocity vectors based on one or more transfer functions that are determined based on the input signals.

7. The apparatus of claim 1 , wherein the one or more audio zones comprise one or more bright zones and one or more dark zones, wherein desired sound pressures and/or desired particle velocity vec

Assignees

• Huawei Tech Co Ltd
• Univ Friedrich Alexander Er

Inventors

• Buerger Michael
• Löllmann Heinrich
• Kellermann Walter
• Helwani Karim
• Grosche Peter
• Lang Yue

Classifications

• H04S2420/13

  Application of wave-field synthesis in stereophonic audio systems · CPC title

• H04R2201/403

  Linear arrays of transducers · CPC title

• H04S7/302 Primary

  Electronic adaptation of stereophonic sound system to listener position or orientation (H04S7/301 takes precedence) · CPC title

• H04R5/02

  Spatial or constructional arrangements of loudspeakers · CPC title

• H04S7/301 Primary

  Automatic calibration of stereophonic sound system, e.g. with test microphone · CPC title