Spectral Correction via Spatial Calibration for Multi-Room Audio

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Current media playback systems face challenges in providing an optimal listening experience across multiple rooms due to variations in acoustic characteristics and spatial placement of playback devices, leading to inconsistent audio quality and synchronization issues.

Innovation Solution

The implementation of spatial and spectral calibration techniques, where playback devices emit calibration audio that is recorded by microphones to determine delays and frequency adjustments, allowing for precise configuration of sound axes to align audio arrival times and compensate for environmental acoustics, thereby enhancing audio quality and synchronization across multiple playback zones.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If playback devices are deployed in multiple rooms without calibration, then system simplicity is maintained, but audio quality consistency and synchronization deteriorate due to varying acoustic characteristics

Engineering Contradiction:

Improveaudio quality consistencyVSAvoidcalibration system complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The calibration system performs automatic self-calibration by having playback devices emit calibration audio signals and recording devices automatically capture and analyze these signals to determine acoustic characteristics and generate calibration data without requiring manual user intervention

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The system uses feedback mechanisms where recorded calibration audio is analyzed to determine acoustic characteristics, and calibration data is continuously refined based on this feedback to improve audio quality consistency across multiple rooms

Inventive Principle:

Principle #23Feedback

2Measurement precision

If calibration procedures are performed manually, then measurement precision can be controlled, but operation complexity and time consumption increase

Engineering Contradiction:

Improveacoustic measurement accuracyVSAvoidcalibration operation simplicity

Core Design Contradiction:

Measurement precisionVSEase of operation

Solution Approach 1:

The calibration system automatically performs measurements by having playback devices emit calibration signals and recording devices capture and analyze these signals without requiring manual user intervention for positioning or measurement control

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The system performs preliminary calibration measurements during device setup or periodically to establish baseline acoustic characteristics before normal operation, eliminating the need for manual calibration procedures during use

Inventive Principle:

Principle #10Preliminary action

3Reliability

If spatial calibration is implemented to improve audio fidelity, then audio synchronization improves, but device complexity and calibration time increase

Engineering Contradiction:

Improveaudio synchronizationVSAvoidcalibration time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The system performs spatial calibration measurements and generates calibration data during initial setup or periodic maintenance periods, so that when audio playback occurs, the calibration is already complete and no time is lost during actual use

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The calibration system operates continuously in the background by periodically re-measuring acoustic characteristics and updating calibration data without interrupting normal audio playback operations

Inventive Principle:

Principle #20Continuity of useful action

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

This approach ensures improved audio fidelity and synchronization by calibrating playback devices to specific listening locations, providing a more uniform and immersive audio experience across different rooms and configurations.

Implementation Method 1

playback devices emit calibration audio that is recorded by microphones to determine delays and frequency adjustments

Methodology Applied

Scientific EffectSound wave detection: Sound

Data Source

PatentUS10448194B2Spectral correction using spatial calibration

Publication Date: 2019.10.15 SONOS INC

AI summary

Example techniques may involve performing aspects of a spectral calibration using an applied spatial calibration. An example implementation may include receiving data representing spatial filters that correspond to respective playback configurations. The implementation may also involve causing the audio drivers to output calibration audio that is divided into a repeating set of frames, the set of frames including a respective frame for each playback configuration. Causing the audio drivers to output the calibration audio may involve causing an audio stage to apply, during each frame, the spatial filter corresponding to the respective playback configuration. The implementation may also include receiving data representing spectral filters that correspond to respective playback configurations, the spectral filters based on the calibration audio output by the audio drivers. When playing back audio content in a given playback configuration, the audio stage may apply a particular spectral filter corresponding to that configuration.