Virtual Speaker VBAP Mixing for Stable Sound Image Localization

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Solution Overview

Problem

Conventional sound image localization techniques, such as VBAP, can result in unstable sound image positioning when users move, leading to a narrower sweet spot range due to the reliance on fewer speakers outputting sound.

Innovation Solution

The use of a sound processing apparatus that calculates and adjusts gains for a larger number of speakers, ensuring all speakers output sound, thereby stabilizing sound image localization and expanding the sweet spot range by performing VBAP across multiple speaker combinations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If three-dimensional VBAP is used to perform sound image localization with three speakers, then the localization precision is improved, but the stability deteriorates when users move because only two speakers output sound in some cases

Engineering Contradiction:
Improvesound image localization precisionVSAvoidsound image localization stability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent combines multiple VBAP calculations using different speaker combinations (three-speaker VBAP and two-speaker VBAP) into a unified gain calculation system. By merging the results of multiple VBAP approaches, the system ensures that all speakers contribute to sound output, thereby maintaining both localization precision and stability during user movement.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent creates a composite gain calculation method that integrates multiple VBAP approaches. Instead of relying on a single VBAP calculation, the system composite the gain values from different speaker combinations, resulting in a more robust sound image localization system that maintains stability across various user positions and movements.

Inventive Principle:
Principle #40Composite materials

2Device complexity

If only two speakers output sound in three-dimensional VBAP, then the device complexity is reduced, but the sweet spot range becomes narrower

Engineering Contradiction:
Improvespeaker output configurationVSAvoidsweet spot range
Core Design Contradiction:
Device complexityVSArea of stationary object

Solution Approach 1:

The patent merges multiple speaker output configurations by combining results from three-speaker VBAP and two-speaker VBAP calculations. This merging approach ensures that all speakers contribute to sound output, effectively expanding the sweet spot range while maintaining manageable system complexity through systematic gain calculation.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP2991384B1Audio processing device, method, and program
Publication Date: 2021.06.02 SONY GROUP CORP
  • EP2991384B1 patent drawingFigure 1
  • EP2991384B1 patent drawingFigure 2
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AI summary

The present technology relates to a sound processing apparatus and method, and a program for enabling more stable localization of a sound image. A virtual speaker is assumed to exist on the lower side among the sides of a tetragon having its corners formed with four speakers surrounding a target sound image position on a spherical plane. Three-dimensional VBAP is performed with respect to the virtual speaker and the two speakers located at the upper right and the upper left, to calculate gains of the two speakers at the upper right and the upper left and the virtual speaker, the gains being to be used for fixing a sound image at the target sound image position. Further, two-dimensional VBAP is performed with respect to the lower right and lower left speakers, to calculate gains of the lower right and lower left speakers, the gains being to be used for fixing a sound image at the position of the virtual speaker. The values obtained by multiplying these gains by the gain of the virtual speaker are set as the gains of the lower right and lower left speakers for fixing a sound image at the target sound image position. The present technology can be applied to sound processing apparatuses.