Spatial Audio Signal Adaptation for Loudspeaker Setup Changes

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Modern audio playback systems face compatibility issues due to varying loudspeaker setups, leading to compromised spatial audio experiences as they often deviate from the original intended configuration, lacking flexibility to maintain the original sound scene's spatial image.

Innovation Solution

An apparatus and method that group loudspeaker channels into segments, decompose them into direct and ambience components, and adjust these components to match the new playback setup, ensuring the perceived direction and envelopment remain consistent with the original setup, even with changes in the number of loudspeakers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the audio signal is adapted to a different loudspeaker setup, then compatibility and flexibility are improved, but the original spatial image and audio quality are compromised

Engineering Contradiction:
Improvecompatibility with different loudspeaker setupsVSAvoidspatial image accuracy
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The audio signal is segmented into multiple frequency bands using filter banks, and each band is processed independently to preserve spatial information while adapting to different loudspeaker configurations. This allows the system to maintain spatial accuracy across multiple frequency ranges simultaneously.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different processing strategies are applied to different frequency bands based on their specific characteristics. Direct sound components and ambience components are separated and processed with locally optimized transfer functions that match the playback loudspeaker setup, ensuring high spatial accuracy for each frequency region.

Inventive Principle:
Principle #3Local quality

2Ease of operation

If the loudspeaker positioning deviates from the recommended setup, then flexibility in setup is improved, but the spatial quality and audio experience are degraded

Engineering Contradiction:
Improvesetup flexibilityVSAvoidspatial audio quality
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The system dynamically adjusts transfer function parameters based on the actual playback loudspeaker configuration. By measuring or detecting the loudspeaker positions and adapting the transfer functions accordingly, the system maintains reliable spatial audio quality regardless of setup variations, allowing flexible positioning without quality degradation.

Inventive Principle:
Principle #35Parameter changes

3Adaptability or versatility

If a complex sound scene with multiple direct sources is processed, then the ability to handle realistic audio scenes is improved, but the processing complexity increases

Engineering Contradiction:
Improvehandling of complex sound scenesVSAvoidprocessing system complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The complex sound scene is segmented into multiple frequency bands, and within each band, direct sound components from different sources are separated using blind source separation techniques. This segmentation approach reduces the computational complexity of handling multiple sources by processing them in parallel across frequency bands rather than simultaneously in the time domain.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Direct sound components are extracted from the mixed audio signal in each frequency band using correlation-based methods. By extracting and processing only the direct sound portions separately from the ambience, the system efficiently handles complex scenes with multiple sources without processing the entire signal with full complexity.

Inventive Principle:
Principle #2Taking out (Extraction)

Data Source

PatentEP2920982B1Segment-wise adjustment of spatial audio signal to different playback loudspeaker setup
Publication Date: 2017.12.20 FRAUNHOFER GESELLSCHAFT ZUR FORDERUNG DER ANGEWANDTEN FORSCHUNG EV
  • EP2920982B1 patent drawingFigure 1
  • EP2920982B1 patent drawingFigure 2
  • EP2920982B1 patent drawingFigure 3

AI summary

Apparatus (100) for adapting a spatial audio signal (2) for an original loudspeaker setup to a playback loudspeaker setup that differs from the original loudspeaker setup. The apparatus comprises a direct-ambience decomposer (130) that is configured to decomposing channel signals in a segment of the original loudspeaker setup into direct sound (D) and ambience components (A), and to determine a direction of arrival of the direct sound components. A direct sound renderer (150) receives a playback loudspeaker setup information and adjusts the direct sound components (D) using the playback loudspeaker setup information so that a perceived direction of arrival of the direct sound components in the playback loudspeaker setup is substantially identical to the direction of arrival of the direct sound components. A combiner (180) combines adjusted direct sound components and possibly modified ambience components to obtain loudspeaker signals for loudspeakers of the playback loudspeaker setup.