Multi-Speaker VBAP Gain Control for Stable Sound Image Localization
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Solution Overview
Problem
Conventional sound image localization techniques using VBAP can result in unstable sound image positioning, especially when users move, leading to a narrower sweet spot range due to the reliance on only two speakers outputting sound while others remain silent.
Innovation Solution
A sound processing apparatus with four or more sound outputting units, utilizing a gain calculating unit to determine and adjust output gains based on positional relationships among different combinations of speakers, ensuring all speakers contribute to maintaining a stable sound image localization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If VBAP is performed using only two or three speakers, then the device complexity is reduced, but the stability of sound image localization deteriorates
Solution Approach 1:
The patent combines the output of multiple speakers (four or more) to achieve stable sound image localization. By merging the contributions of all surrounding speakers rather than selecting only two or three, the system maintains reliable localization across different user positions and movement states.
Solution Approach 2:
The patent dynamically adjusts the gain coefficients for each speaker based on the user's position and movement. The gain calculating unit continuously computes optimal gains for all speakers surrounding the user, allowing the system to adapt to dynamic listening conditions and maintain stable localization.
2Loss of energy
If only two speakers output sound in three-dimensional VBAP, then the loss of energy is reduced, but the sweet spot range becomes narrower
Solution Approach 1:
The patent applies local quality by assigning different gain coefficients to different speakers based on their positional relationships with the user. Each speaker contributes differently to the sound image localization, with gains optimized for their specific spatial location relative to the user's ears.
Solution Approach 2:
The patent uses partial action by having all speakers output sound at optimized gain levels rather than only two speakers at full power. This distributed approach expands the sweet spot range while managing energy consumption through gain control.
3Reliability
If gain adjustment is performed based on positional relationships among multiple speakers, then the stability of sound image localization is improved, but the device complexity increases
Solution Approach 1:
The gain calculating unit automatically computes optimal gain coefficients for all speakers based on their positional relationships with the user. The system self-adjusts the gains without manual intervention, using the spatial configuration of speakers and user position to determine appropriate output levels for stable localization.
Data Source
AI summary
The present technology relates to a sound processing apparatus and a sound processing system 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.