3D Sound Image Localization Using Virtual Speaker Gain Control
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Solution Overview
Problem
Existing sound image localization techniques, such as VBAP, can result in unstable localization and a narrow sweet spot range when users move, especially with three-dimensional setups where only two speakers output sound, leading to a perception of sound image movement in unintended directions.
Innovation Solution
A sound processing apparatus and system utilizing four or more sound outputting units, with a gain calculating unit determining output gains based on positional relationships among sound outputting units to stabilize sound image localization, ensuring all units output sound and employing virtual speakers to maintain image stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If three-dimensional VBAP is used with three speakers, then the sound image can be localized at the target position, but only two speakers output sound while one speaker is controlled not to output sound, causing unstable localization when the user moves
Solution Approach 1:
The patent combines the output of multiple speakers (four or more) to reproduce sound images, rather than using only two or three speakers. This merging approach ensures that all speakers contribute to sound image reproduction, providing stable localization even when users move, as the sound image is maintained by the collective output of all speakers rather than relying on a limited subset.
2Measurement precision
If only two speakers output sound in three-dimensional VBAP, then the sound image can be fixed at the target position, but the sweet spot range becomes narrower and localization becomes unstable
Solution Approach 1:
The patent merges the acoustic contributions of all four or more speakers to create a broader and more stable sound image localization. By having all speakers output sound simultaneously with appropriately calculated gains, the system expands the sweet spot range and maintains stable localization across a wider area, rather than relying on a narrow sweet spot from limited speaker combinations.
3Measurement precision
If gain adjustment is performed based on positional relationships, then the sound image can be fixed at the target position, but the localization becomes unstable when users move
Solution Approach 1:
The patent implements dynamic gain adjustment that adapts to user movement. The gain calculating unit continuously calculates appropriate gain values based on the positional relationships between all speakers and the target sound image position, allowing the system to maintain stable localization even when users move. This dynamic approach ensures all speakers remain actively engaged in sound image reproduction throughout user movement.
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.