DEVICE AND METHOD FOR SPATIALLY SELECTIVE AUDIO REPRODUCTION

• US 20160088388A1
• Filed: 11/30/2015
• Published: 03/24/2016
• Est. Priority Date: 05/31/2013
• Status: Active Grant

• Current Assignee: Brandenburg Labs GmbH
• Original Assignee: Fraunhofer Gesellschaft Zur Foerderung Der Angewandten Forsching E.V.
• Inventors: SPORER, Thomas, FRANCK, Andreas, SLADECZEK, Christoph
• Granted Patent: US 9,813,804 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H04R 1/323 for loudspeakers H04R1/34 and H04R1/40 take precedence
• CPC Class Codes: H04R 2203/12 Beamforming aspects for stereophonic sound reproduction with loudspeaker arrays
• CPC Class Codes: H04R 2227/001 Adaptation of signal processing in PA systems in dependence of presence of noise
• CPC Class Codes: H04R 2430/01 Aspects of volume control, not necessarily automatic, in sound systems
• CPC Class Codes: H04R 2430/20 Processing of the output signals of the acoustic transducers of an array for obtaining a desired directivity characteristic H04R2203/12 takes precedence
• CPC Class Codes: H04R 27/00 Public address systems circuits for preventing acoustic reaction H04R3/02; circuits for distributing signals to loudspeakers H04R3/12; monitoring or testing arrangements for public address systems H04R29/007; amplifiers H03F
• CPC Class Codes: H04R 5/02 Spatial or constructional arrangements of loudspeakers

Abstract

A more clear-cut separation of a first audio signal within a first region of a sonication area of a plurality of loudspeakers is achieved in that a calculator calculates that version of the audio signals which results from the spatially selective reproduction of the audio signals at this first region, in that a masking threshold is calculated as a function of the version of that audio signal which is to be separated from the one or more other audio signals at this region, and in that the emission of the audio signals for spatially selective reproduction to the outputs of the plurality of loudspeakers is influenced as a function of a comparison of the masking threshold with the version of the one or more other, i.e. spurious, audio signals.

Claims

1. A device for spatially selective audio reproduction, comprising

an input for first and second audio signals;

an output for a plurality of loudspeakers;

a beamforming processor connected between the input, on the one hand, and the output, on the other hand, and is configured to emit the first and second audio signals for spatially selective reproduction to the loudspeakers via the output;

a calculator configured to calculate, by means of a propagation model, for the first and second audio signals a respective version of the respective audio signal which results from the spatially selective reproduction in a first region of a sonication area of the loudspeakers;

a masking threshold calculator configured to calculate, via a psychoacoustic model, a masking threshold as a function of the version of the first audio signal; and

an adaptor configured to influence, as a function of a comparison of the masking threshold with the version of the second audio signal, the emission of the first and second audio signals for spatially selective reproduction to the loudspeakers via the output;

the beamforming processor being configured to achieve emission of the first and second audio signals for spatially selective reproduction to the output by performing beamforming on at least the second audio signal, the beamforming processor comprising several modes for performing beamforming which differ from one another with regard to a quality of suppression of the second audio signal at the first region for different frequency domains,

the adaptor being configured to vary the beamforming by switching from a currently used mode to a different mode as a function of the comparison.

2. The device as claimed in claim 1, further comprising a plurality of loudspeakers.

3. The device as claimed in claim 1, wherein the beamforming processor is configured to perform beamforming on the second audio signal so as to acquire a first plurality of loudspeaker signals, and to apply the loudspeaker signals acquired from the second audio signal to the loudspeakers via the output.

4. The device as claimed in claim 3, wherein the beamforming processor is configured to subject the first audio signal to beamforming so as to acquire a second plurality of loudspeaker signals, and to apply the second plurality of loudspeaker signals to the loudspeakers via the output by means of superposition with the first plurality of loudspeaker signals.

5. The device as claimed in claim 4, wherein the beamforming processor is configured to perform the beamforming on the first and second audio signals differently—

for spatially selective reproduction in different regions of the sonication area—

so that for each region, one of the audio signals represents a target signal, whereas the respectively other audio signal represents a spurious signal in the respective region.

6. The device as claimed in claim 5, wherein

the calculator is configured to calculate, by means of the propagation model, for each audio signal and for each of the different regions a respective version of the respective audio signal which results from the spatially selective reproduction in the respective region of the sonication area of the loudspeakers,

a masking threshold calculator configured to calculate a masking threshold for each region of the sonication area as a function of the version, which results from the spatially selective reproduction in the respective region of the sonication area of the loudspeakers, of that audio signal which represents a target signal for the respective region;

and

the adaptor is configured to influence the emission of the audio signals for spatially selective reproduction to the loudspeakers via the output on the basis of a comparison of the masking threshold for each of the regions with an interference which results from the version of that audio signal which represents a spurious signal in the respective region.

7. The device as claimed in claim 6, wherein the number of the audio signals is larger than two.

8. The device as claimed in claim 1, wherein the masking threshold calculator is configured to take into account a background audio signal when calculating the masking threshold as a function of the version of the first audio signal.

9. The device as claimed in claim 1, wherein the adaptor is configured to control the beamforming processor such that within frequency domains in which the version of the second audio signal exceeds the masking threshold, the second audio signal is globally reduced in the spatially selective reproduction.

10. The device as claimed in claim 1, wherein the adaptor is configured to control the beamforming processor such that within frequency domains in which the version of the second audio signal exceeds the masking threshold, the first audio signal is globally reduced in the spatially selective reproduction.

11. The device as claimed in claim 1, wherein the adaptor is configured to limit the change in the emission of the first and second audio signals with regard to an absolute value and/or with regard to a rate of change of the value of the change.

12. The device as claimed in claim 1, wherein the calculator is configured to take temporal and spectral auditive masking effects into account in the calculation.

13. A method for spatially selective audio reproduction by means of a beamforming processor connected between an input for first and second audio signals and an output for a plurality of loudspeakers, said beamforming processor being configured to emit the first and second audio signals for spatially selective reproduction to the loudspeakers via the output, comprising:

calculating, by means of a propagation model for the first and second audio signals, a respective version of the respective audio signal which results from the spatially selective reproduction in a first region of a sonication switch of the loudspeakers;

as a function of the version of the first audio signal, calculating a masking threshold via a psychoacoustic model; and

as a function of a comparison of the masking threshold with the version of the second audio signal, influencing the emission of the first and second audio signals for spatially selective reproduction to the loudspeakers via the output;

the beamforming processor being configured to achieve emission of the first and second audio signals for spatially selective reproduction to the output by performing beamforming on at least the second audio signal, the beamforming processor comprising several modes for performing beamforming which differ from one another with regard to a quality of suppression of the second audio signal at the first region for different frequency domains,

said influencing comprising varying the beamforming by switching from a currently used mode to a different mode as a function of the comparison.

14. A computer program comprising a program code for performing the method as claimed in claim 13, when the program runs on a computer.