Method and device for enhanced sound field reproduction of spatially encoded audio input signals

Abstract

A method for sound field reproduction into a listening area of spatially encoded first audio input signals according to sound field description data using an ensemble of physical loudspeakers. The method includes computing reproduction subspace description data from loudspeaker positioning data describing the subspace in which virtual sources can be reproduced with the physically available setup. Then, second and third audio input signals with associated sound field description data, in which second audio input signals include spatial components of the first audio input signals located within the reproducible subspace and third audio input signals include spatial components of the first audio input signals located outside of the reproducible subspace. A spatial analysis is performed on second audio input signals to extract fourth audio input signals corresponding to localizable sources within the reproducible subspace with associated source positioning data. Components of second audio input signals after spatial analysis are merged with third audio input signals into fifth audio input signals with associated sound field description data for reproduction within the reproducible subspace. Loud-speaker alimentation signals are computed from fourth and fifth audio input signals.

The invention claimed is: 
     
       1. A method for sound field reproduction into a listening area of spatially encoded first audio input signals according to sound field description data using an ensemble of physical loudspeakers, comprising the steps of:
 computing reproduction subspace description data from loudspeaker positioning data describing the subspace in which virtual sources can be reproduced with the physically available setup; 
 extracting second audio input signals and third audio input signals with associated sound field description data, wherein second audio input signals comprise spatial components of the first audio input signals located within the reproducible subspace and third audio input signals comprise spatial components of the first audio input signals located outside of the reproducible subspace; 
 performing a spatial analysis on second audio input signals for extracting fourth audio input signals corresponding to localizable sources within the reproducible subspace with associated source positioning data; 
 merging remaining components of second audio input signals after spatial analysis and third audio input signals into fifth audio input signals with associated sound field description data for reproduction within the reproducible subspace; and, 
 computing loudspeaker alimentation signals from fourth audio input signals and fifth audio input signals according to loudspeaker positioning data, localizable sources positioning data and sound field description data. 
 
     
     
       2. The method for sound field reproduction into a listening area of spatially encoded first audio input signals according to sound field description data using an ensemble of physical loudspeakers according to  claim 1 , wherein the sound field description data correspond to eigen solutions of the wave equation: plane waves, spherical harmonics, or cylindrical harmonics. 
     
     
       3. The method for sound field reproduction into a listening area of spatially encoded first audio input signals according to sound field description data using an ensemble of physical loudspeakers according to  claim 1 , wherein the sound field description data correspond to incoming directions in a channel-based format. 
     
     
       4. The method for sound field reproduction into a listening area of spatially encoded first audio input signals according to sound field description data using an ensemble of physical loudspeakers according to  claim 1 , wherein the spatial analysis comprises the steps of:
 converting, as necessary, the second audio input signals into spherical (3D) or cylindrical (2D) harmonic components; 
 identifying directional of arrival/sound field description data of main localizable sources within the reproducible subspace; and, 
 forming beam patterns by combination of spherical harmonics having main lobe in the direction of the estimated direction of arrival in order for extracting the fourth audio input signals from the second audio input signals. 
 
     
     
       5. The method for sound field reproduction into a listening area of spatially encoded first audio input signals according to sound field description data using an ensemble of physical loudspeakers according to  claim 4 , wherein the sound field description data are estimated using a subspace directional of arrival estimate method. 
     
     
       6. The method for sound field reproduction into a listening area of spatially encoded first audio input signals according to sound field description data using an ensemble of physical loudspeakers according to  claim 5 , wherein the sound field description data are estimated using a subspace directional of arrival estimate method derived from a MUSIC-or ESPRIT-based algorithm, operating in spherical (3D) or cylindrical (2D) harmonics domain. 
     
     
       7. The method for sound field reproduction into a listening area of spatially encoded first audio input signals according to sound field description data using an ensemble of physical loudspeakers according to  claim 1 , wherein the computation of the reproducible subspace description data are computed according to the loudspeaker positioning data and the listening area description data. 
     
     
       8. The method for sound field reproduction into a listening area of spatially encoded first audio input signals according to sound field description data using an ensemble of physical loudspeakers according to  claim 1 , wherein the computation of loudspeaker alimentation signals is performed according to loudspeaker positioning data, the listening area description data, localizable sources positioning data and sound field description data. 
     
     
       9. A device for sound field reproduction into a listening area of spatially encoded first audio input signals according to sound field description data using an ensemble of physical loudspeakers, comprising:
 a reproducible subspace computation device for computing reproduction subspace description data from loudspeaker positioning data describing the subspace in which virtual sources can be reproduced with the physically available setup; 
 a reproducible subspace audio selection device for extracting second audio signals and third audio input signals with associated sound field description data, wherein the second audio input signals comprise spatial components of the first audio input signals located within the reproducible subspace and the third audio input signals comprise spatial components of the first audio input signals located outside of the reproducible subspace; 
 a sound field transformation device for extracting fourth audio input signals with associated source positioning data corresponding to localizable sources from second audio input signals within the reproducible subspace and for merging remaining components of the second audio input signals after spatial analysis and the third audio input signals into fifth audio input signals with associated sound field description data for reproduction within the reproducible subspace; and, 
 a spatial sound rendering device for computing loudspeaker alimentation signals from fourth input signals and fifth audio input signals according to loudspeaker positioning data, localizable sources positioning data and sound field description data. 
 
     
     
       10. The device for sound field reproduction into a listening area of spatially encoded first audio input signals according to sound field description data using an ensemble of physical loudspeakers according to  claim 9 , wherein the reproducible subspace computation device computes the reproducible subspace description data according to the loudspeaker positioning data and the listening area description data. 
     
     
       11. The device for sound field reproduction into a listening area of spatially encoded first audio input signals according to sound field description data using an ensemble of physical loudspeakers according to  claim 9 , wherein the spatial sound rendering device computes loudspeaker alimentation signals according to loud-speaker positioning data, the listening area description data, localizable sources positioning data and sound field description data.