Spatially Extended Sound Synthesis With Elementary Spatial Sectors

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Solution Overview

Problem

Existing sound reproduction methods struggle to realistically render spatially extended sound sources, such as large objects like musical instruments or ambient sounds, due to limitations in modeling their size and occlusion effects, especially in virtual reality scenarios where listener position changes are common.

Innovation Solution

A method for synthesizing spatially extended sound sources (SESS) using elementary spatial sectors, incorporating frequency-selective attenuation from occluding objects and storing pre-calculated binaural cues in a lookup table, allowing for efficient and flexible rendering across different listener positions and orientations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If point source rendering is used, then the reproduction system is simple, but the spatial extent and realism of sound sources cannot be modeled accurately

Engineering Contradiction:

Improvereproduction system complexityVSAvoidspatial extent modeling accuracy

Core Design Contradiction:

Device complexityVSManufacturing precision

Solution Approach 1:

The sound source is divided into multiple virtual point sources distributed across a spatial grid, where each point source contributes to the overall sound field. This segmentation allows the system to represent extended sound sources like musical instruments or ambient sounds by combining contributions from multiple localized sources, thereby achieving realistic spatial extent without requiring a completely complex system architecture.

Inventive Principle:

Principle #1Segmentation

2Ease of manufacture

If conventional sound reproduction methods are used, then the system is easy to implement, but occlusion effects and frequency damping for spatially extended sources cannot be rendered

Engineering Contradiction:

Improvesystem implementation easeVSAvoidocclusion effect rendering capability

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

Different regions of the spatial grid are assigned different acoustic characteristics based on their location relative to occluding objects. When a virtual point source is positioned behind an occluding object, the system applies frequency-selective attenuation specific to that region, creating the illusion of occlusion effects. This allows realistic rendering of spatially extended sources with occlusion while maintaining ease of implementation through localized processing.

Inventive Principle:

Principle #3Local quality

3Manufacturing precision

If spatially extended sound sources are rendered with high accuracy, then realism is improved, but computational complexity and processing requirements increase

Engineering Contradiction:

Improvesound source rendering accuracyVSAvoidcomputational complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The system pre-calculates and stores acoustic characteristics for multiple virtual point sources at different spatial positions before actual rendering occurs. This preliminary action allows the system to quickly retrieve and combine pre-computed acoustic data during real-time rendering, achieving high rendering accuracy for spatially extended sources without the computational burden of calculating everything from scratch.

Inventive Principle:

Principle #10Preliminary action

4Adaptability or versatility

If listener position changes are supported in virtual reality, then adaptability is improved, but maintaining consistent audio quality and timbre becomes difficult

Engineering Contradiction:

Improvelistener position adaptabilityVSAvoidaudio quality consistency

Core Design Contradiction:

Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The system dynamically adjusts the acoustic characteristics of virtual point sources based on the listener's position and orientation. As the listener moves, the system recalculates which virtual point sources are most relevant and adjusts their acoustic properties in real-time to maintain consistent spatial relationships and audio quality. This dynamic adaptation ensures that the perceived sound field remains stable and accurate despite changes in listener position.

Inventive Principle:

Principle #15Dynamics

Data Source

PatentEP4430851B1Apparatus, method and computer program for synthesizing a spatially extended sound source using elementary spatial sectors

Publication Date: 2025.10.29 FRAUNHOFER GESELLSCHAFT ZUR FORDERUNG DER ANGEWANDTEN FORSCHUNG EV

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Figure 2b~3
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AI summary

An apparatus for synthesizing a spatially extended sound source (SESS) (7000), comprises: a storage (200, 2000) for storing rendering data items for different elementary spatial sectors covering a rendering range for a listener; a sector identification processor (4000) for identifying, from the different elementary spatial sectors, a set of elementary spatial sectors belonging to the spatially extended sound source based on listener data and spatially extended sound source data; a target data calculator (5000) for calculating target rendering data from the rendering data items for the set of elementary spatial sectors; and an audio processor (300, 3000) for processing an audio signal representing the spatially extended sound source using the target rendering data.