Decentralized Wave Field Synthesis Modules for Scalable Spatial Audio

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Solution Overview

Problem

Current wave field synthesis systems face challenges in recreating the acoustic conditions of a recording room due to the large number of sound transducers required, high computational effort, and inability to represent rapid movements of sound sources with accurate Doppler effects, especially when trying to build a two-dimensional acoustic curtain or change listener positions.

Innovation Solution

A decentralized modular structure for sound transducers, where each module processes audio signals and data autonomously, reducing the need for centralized computing power and data transmission, allowing for rapid updates and scalable systems that can represent multiple sound sources and their reflections without increasing computational load.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a two-dimensional acoustic curtain is built with a large number of sound transducers to completely reconstruct acoustic conditions, then the accuracy of spatial reproduction and reflection reconstruction is improved, but the device complexity and computational effort increase enormously

Engineering Contradiction:
Improvespatial reproduction accuracyVSAvoidsystem complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent divides the large-scale acoustic curtain into multiple smaller modules, each with its own control unit. This segmentation allows the system to achieve two-dimensional spatial reproduction without requiring a single centralized system to process all transducers simultaneously, thereby managing device complexity while maintaining spatial accuracy.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces a vertical dimension to the system architecture by stacking modules in multiple levels. This dimensional expansion allows the acoustic curtain to achieve complete spatial reconstruction including overhead reflections, improving spatial reproduction accuracy without proportionally increasing the complexity of individual control units.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Manufacturing precision

If sound transducers are arranged at a small distance from one another to avoid aliasing effects, then the quality of wave front reconstruction is improved, but the number of transducers and device complexity increase

Engineering Contradiction:
Improvewave front reconstruction qualityVSAvoidtransducer array complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent implements segmentation by organizing closely-spaced transducers into modular groups, where each module contains a manageable subset of transducers. This allows high-density transducer arrangements for accurate wave front reconstruction while keeping individual module complexity low and manageable.

Inventive Principle:
Principle #1Segmentation

3Reliability

If all reflections of the recording room are reconstructed at their correct starting point, then the realism of acoustic reproduction is improved, but the computational effort and data processing requirements increase significantly

Engineering Contradiction:
Improveacoustic reproduction realismVSAvoidcomputational power
Core Design Contradiction:
ReliabilityVSPower

Solution Approach 1:

The patent distributes the computational task of reconstructing acoustic reflections across multiple independent control units, each handling a specific module. This segmentation of computational load enables realistic acoustic reproduction with multiple reflections without overwhelming a single processor, as each control unit independently calculates and outputs its portion of the acoustic scene.

Inventive Principle:
Principle #1Segmentation

4Measurement precision

If the positions of virtual sound sources are updated rapidly to represent continuous movement, then the accuracy of motion representation including Doppler effects is improved, but the data transmission rate and processing speed requirements increase

Engineering Contradiction:
Improvemotion representation accuracyVSAvoiddata update speed
Core Design Contradiction:
Measurement precisionVSSpeed

Solution Approach 1:

The patent divides the data transmission and processing workload by assigning different spatial zones or modules to different control units. Each control unit independently updates and transmits position data for virtual sound sources within its jurisdiction, reducing the overall data transmission rate required while maintaining accurate motion representation through parallel processing.

Inventive Principle:
Principle #1Segmentation

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Enables the creation of scalable wave field synthesis systems that can accurately represent rapid movements of sound sources with natural Doppler effects, overcoming limitations of centralized systems by distributing computing power and reducing data transmission needs, allowing for larger acoustic curtains and more complex sound field reconstructions.

Implementation Method 1

the wave fronts emanating from a natural sound source can be physically reconstructed according to the Huygens principle. A virtual sound source is created at the position of the natural sound source from the elementary waves of a large number of individually controlled sound transducers.

Methodology Applied
Scientific EffectAcoustic wave propagation: Sound

Implementation Method 2

In order to completely reconstruct the acoustic conditions in the recording room, it would be necessary to build up the acoustic curtain around the listener so that all reflections of the recording room can be generated at their correct starting point.

Methodology Applied
Scientific EffectAcoustic reflection: Reflection

Data Source

PatentEP3061271B1Wave field synthesis system
Publication Date: 2018.04.04 HOLOPLOT GMBH
  • EP3061271B1 patent drawingFigure 1~2

AI summary

The present invention describes an apparatus comprising sound transducers based on the principle of wave field synthesis that can be compiled in a local design to form a freely scalable overall magnitude. The local design of the system ensures the free scalability. The computation complexity in the central system remains independent of the number of sound transducers in the overall system. In previously known apparatuses for reconstructing a sound field based on the principle of wave field synthesis, the demands on the central system rise with the number of sound transducers that it covers. For this reason too, the wave field synthesis is usually reduced to the horizontal plane of the listener, and the third dimension is lost in the reproduction of the sound events. The solution according to the invention allows the model-based approach of wave field synthesis to be also used to construct two-dimensional apparatuses of arbitrary magnitude from sound transducers based on the principle of wave field synthesis that are able to implement rapid changes of location for the virtual sound sources with the associated Doppler effects without artefacts. In this case, the requisite computation power can therefore be distributed locally because the volume of data to be transferred between the subsystems remains comparatively small.