Wireless Audio Speaker Synchronization via Delay Measurement

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Solution Overview

Problem

In wireless audio systems, adjusting output levels and timings for multiple speakers playing the same audio source is complex due to variations in sound transmission delay and input-to-output ratios, which are affected by speaker arrangement, obstacles, and orientation, leading to suboptimal audio quality at the listening position.

Innovation Solution

A controller with a microphone measures the delay period and input-to-output ratio for each speaker, adjusting their output timings and levels to ensure synchronized and optimal audio delivery, and determines speaker grouping and audio modes based on received radio wave strengths.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If output levels and output timings are adjusted individually for each speaker, then audio quality at listening position can be optimized, but setting task becomes complicated

Engineering Contradiction:

Improveaudio quality optimizationVSAvoidsetting task complexity

Core Design Contradiction:

Measurement precisionVSEase of operation

Solution Approach 1:

The system automatically measures delay periods and input-to-output ratios for each speaker, and adjusts output timings and levels without requiring manual user configuration. The controller autonomously optimizes audio parameters by having each speaker output test signals and measuring the actual sound characteristics at the listening position.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The system dynamically adjusts output timing parameters and output level parameters for each speaker based on measured delay periods and input-to-output ratios. These parameter changes are automatically applied to optimize audio quality without manual intervention.

Inventive Principle:

Principle #35Parameter changes

2Ease of operation

If distance-based adjustment is used for speaker output, then setting task complexity is reduced, but audio optimization is insufficient due to variations in sound transmission

Engineering Contradiction:

Improvesetting task simplicityVSAvoidaudio optimization accuracy

Core Design Contradiction:

Ease of operationVSMeasurement precision

Solution Approach 1:

The system measures the actual sound signals from each speaker using a microphone at the listening position, obtaining feedback on delay periods and input-to-output ratios. This feedback is used to automatically adjust output timing and level parameters, ensuring accurate optimization that accounts for actual sound transmission conditions including walls, obstacles, and speaker orientation.

Inventive Principle:

Principle #23Feedback

3Area of stationary object

If multiple speakers output the same audio source, then audio coverage is improved, but synchronization and balance become difficult to achieve

Engineering Contradiction:

Improveaudio coverage areaVSAvoidsynchronization precision

Core Design Contradiction:

Area of stationary objectVSManufacturing precision

Solution Approach 1:

The system performs preliminary measurements of delay periods for each speaker before actual audio playback. Based on these pre-measured delay periods, the controller calculates and applies appropriate output timing adjustments to ensure all speakers are synchronized when playing the same audio source, achieving precise coordination across multiple speakers.

Inventive Principle:

Principle #10Preliminary 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 that audio signals from multiple speakers are synchronized and optimized at the listening position, providing improved audio quality by adjusting output characteristics and excluding non-coherent speakers, thus enhancing the listening experience.

Implementation Method 1

a microphone of a controller held by a listener collects a sound of an audio signal output from a wireless speaker

Methodology Applied

Scientific EffectMicrophone transduction:

Implementation Method 2

processing of measuring a delay period, which is a difference between an output time of the audio signal from the wireless speaker and an input time of the audio signal into the microphone of the controller

Methodology Applied

Scientific EffectTime delay measurement:

Implementation Method 3

This wireless communication system measures a distance to a wireless device based on a received radio wave strength of a wireless signal output from the wireless device

Methodology Applied

Scientific EffectRadio wave propagation:

Data Source

PatentUS10587968B2Wireless audio system, controller, wireless speaker, and computer readable system

Publication Date: 2020.03.10 D & M HOLDINGS INC

AI summary

[Problem] In the case where an audio signal of the same source is output from a plurality of speakers, the speakers are adjusted so that the audio signals become optimal at a listening position. [Solution] Processing in which an audio signal output from a wireless speaker 1 is collected by a microphone of a controller 2 carried by a listener and a delay time is measured that is the difference between an output time of the audio signal from the wireless speaker 1 and an input time of the audio signal to the microphone of the controller 2 is performed on a plurality of the wireless speakers 1 that output an audio signal of the same source, and the delay times of the audio signals from these respective wireless speakers 1 are measured. Output timings of these respective wireless speakers 1 are adjusted on the basis of these delay times.