3D VBAP Speaker Gain Control 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, causing the sound image to move in unintended directions.
Innovation Solution
The use of a sound processing apparatus and method that involves a larger number of speakers, specifically four or more, to output sound, allowing for more stable sound image localization by calculating gains for different speaker combinations to ensure the sound image moves in the same direction as the user, thereby widening the sweet spot range.
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 a target position, but only two speakers output sound in some cases causing unstable localization when the user moves
Solution Approach 1:
The patent combines multiple speaker groups (three-speaker groups and two-speaker groups) into a unified sound output system. By integrating both group types and controlling their respective gains, the system ensures that sound is always output from multiple speakers simultaneously, preventing the localization instability that occurs when only two speakers are active in three-dimensional VBAP
Solution Approach 2:
The patent dynamically adjusts the gain parameters of different speaker groups based on the sound image position and user movement. By changing the gain values of three-speaker groups and two-speaker groups according to their contribution to sound image localization, the system maintains stable localization even when the user moves, rather than relying on fixed speaker activation patterns
2Ease of operation
If only two speakers output sound in three-dimensional VBAP, then the system simplifies operation, but the sound image moves in different directions from user movement causing unstable localization
Solution Approach 1:
The patent merges two-speaker group output with three-speaker group output in a unified gain control system. By calculating and combining the gains from both group types based on the sound image position, the system maintains simple operation while ensuring that sound always comes from multiple speakers, thereby preventing the directional mismatch between user movement and sound image movement
Solution Approach 2:
The patent introduces a gain calculating unit as an intermediary that processes the sound image position information and determines the appropriate gain values for both two-speaker groups and three-speaker groups. This intermediary ensures that the simplified two-speaker operation does not cause localization instability by mediating the contribution of additional speakers through calculated gain adjustments
Data Source
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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.