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 that calculates output gains for four or more speakers based on their positional relationships to stabilize sound image localization by ensuring all speakers contribute to sound output, thereby maintaining consistent sound image positioning during user movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If VBAP is performed using three speakers (three-dimensional VBAP), then the sound image can be fixed at the target position, but only two speakers among the three speakers output sound in some cases, causing unstable localization when the user moves
Solution Approach 1:
The patent combines the output of multiple speakers (four or more) to produce the sound image, rather than relying on only two or three speakers. By merging the contributions of all surrounding speakers, the system achieves both accurate localization and stable performance during user movement, resolving the contradiction between localization precision and reliability.
Solution Approach 2:
The patent makes all four or more speakers around the localization position contribute to sound output simultaneously, rather than limiting functionality to only two or three speakers. This multi-functional approach ensures that any speaker can participate in maintaining the sound image, improving both accuracy and stability during user movement.
2Measurement precision
If only two speakers output sound while others remain silent, then the sound image can be positioned accurately, but the sweet spot range becomes narrower and localization becomes unstable during user movement
Solution Approach 1:
The patent merges the sound output from four or more speakers to create the sound image, expanding the effective sound field coverage. This combining approach maintains precise positioning while widening the sweet spot range, allowing users to move more freely without losing localization accuracy.
Solution Approach 2:
The patent transitions from using only two speakers (one-dimensional approach) to using four or more speakers distributed in three-dimensional space around the localization position. This dimensional expansion increases the coverage area and sweet spot range while maintaining positioning accuracy.
3Reliability
If four or more speakers are used to widen the sweet spot range, then localization stability improves, but the complexity of gain calculation increases due to multiple combinations
Solution Approach 1:
The patent segments the gain calculation process into two distinct stages: first calculating virtual gains for each speaker based on its positional relationship to the sound image, then calculating ultimate output gains by summing contributions from all speakers. This segmentation simplifies the overall complexity while maintaining stability.
Solution Approach 2:
The patent performs preliminary gain calculation for each speaker individually based on its position relative to the sound image, before combining the results. This preliminary action simplifies the subsequent combination step and reduces overall computational complexity while ensuring localization stability.
Data Source
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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.