Spatially Extended Sound Reproduction With Listener-Position Adaptation
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Solution Overview
Problem
Existing audio reproduction methods fail to accurately represent spatially extended sound sources, such as musical instruments or ambient sounds, due to their reliance on point sources, which distort the true sound characteristics and are limited by listener position, especially in virtual and augmented reality scenarios with 6 degrees of freedom.
Innovation Solution
A method and apparatus that calculate a projection of a two-dimensional or three-dimensional hull of the sound source onto a projection plane using the listener's position, determining positions for multiple sound sources, and render these sources with associated sound signals to recreate the spatially extended sound source, reducing the number of required point sources and maintaining sound quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If point sources are used to reproduce sound, then the reproduction system is simple, but the spatial extent and realism of the sound source is lost
Solution Approach 1:
The spatially extended sound source is segmented into multiple virtual sound sources positioned at different locations within the sound source's spatial extent. Each virtual sound source is assigned a portion of the original sound signal, allowing the system to represent the spatial distribution of the sound source while maintaining manageable complexity through systematic segmentation of the sound field.
2Manufacturing precision
If multiple sound sources are used to represent spatial extent, then the realism improves, but the computational overhead increases
Solution Approach 1:
The system pre-calculates and stores transfer functions for multiple predetermined listener positions around the sound source. When reproduction is needed, the appropriate pre-computed transfer functions are selected and applied directly, avoiding real-time calculation of complex spatial audio transformations and significantly reducing computational overhead during actual playback.
Solution Approach 2:
The system dynamically selects and interpolates between pre-computed transfer functions based on the actual listener position. This dynamic adaptation allows accurate spatial representation for any listener location while maintaining computational efficiency by leveraging pre-calculated data and simple interpolation rather than full real-time simulation.
3Measurement precision
If the reproduction system adapts to listener position changes, then the spatial accuracy improves, but the system complexity increases
Solution Approach 1:
The system uses a universal set of pre-computed transfer functions that serve multiple listener positions simultaneously. A single collection of transfer functions, calculated for various predetermined positions, can serve any listener position through selection and interpolation, making the system universally applicable without requiring position-specific processing pipelines or additional hardware for each possible listener location.
Data Source
AI summary
An apparatus for reproducing a spatially extended sound source having a defined position and geometry in a space includes an interface for receiving a listener position; a projector for calculating a projection of a two-dimensional or three-dimensional hull associated with the spatially extended sound source onto a projection plane using the listener position, information on the geometry of the spatially extended sound source, and information on the position of the spatially extended sound source; a sound position calculator for calculating positions of at least two sound sources for the spatially extended sound source using the projection plane; and a renderer for rendering the at least two sound sources at the positions to obtain a reproduction of the spatially extended sound source having two or more output signals, wherein the renderer is configured to use different sound signals for the different positions.