Adaptive Audio Delay Calibration for Wireless Loudspeakers

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Solution Overview

Problem

Existing methods struggle to synchronize multiple Bluetooth wireless audio devices from different brands or with different specifications, leading to desynchronization issues that affect audio quality.

Innovation Solution

A method involving a multimedia device that transmits probe signals with adaptive audio patterns to determine signal quality and audio delay, allowing for dynamic calibration and synchronization of multiple loudspeakers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a fixed calibration pattern is used for Bluetooth speakers, then synchronization can be achieved for speakers of the same brand or type, but it becomes impossible to synchronize speakers from different manufacturers with different specifications

Engineering Contradiction:
Improvesynchronization accuracyVSAvoidcompatibility with different device types
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent applies dynamics by making the calibration pattern adaptive rather than fixed. The system dynamically adjusts the calibration pattern based on the specific characteristics of each Bluetooth speaker, including its latency and audio processing capabilities. This allows the same calibration system to work effectively across different manufacturers and device types while maintaining synchronization accuracy.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes parameters of the calibration pattern based on measured device characteristics. By measuring the latency and audio response of each speaker and adjusting the calibration pattern parameters accordingly, the system achieves compatibility across diverse devices while preserving synchronization precision.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If multiple Bluetooth speakers with different latencies are synchronized using a fixed calibration pattern, then devices of the same type can be synchronized, but devices from different manufacturers cannot be perfectly synchronized

Engineering Contradiction:
Improvesynchronization reliabilityVSAvoidcross-manufacturer compatibility
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent implements feedback by measuring the actual audio response and latency of each Bluetooth speaker, then using this information to adjust the calibration pattern. This closed-loop approach ensures that speakers from different manufacturers with varying latencies can be synchronized reliably by adapting to their specific characteristics.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system dynamically adapts the calibration process to each speaker's characteristics. By making the calibration pattern flexible and responsive to measured device parameters, the system achieves both synchronization reliability and cross-manufacturer compatibility.

Inventive Principle:
Principle #15Dynamics

3Reliability

If desynchronization exceeds 20 milliseconds in a Bluetooth speaker system, then audio quality is strongly degraded, but achieving synchronization across devices with different specifications is difficult

Engineering Contradiction:
Improveaudio qualityVSAvoidcalibration system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies self-service by enabling the calibration system to automatically measure device characteristics and adjust calibration patterns without manual intervention. This automation maintains audio quality by ensuring synchronization while reducing the complexity of deployment and configuration.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The system performs preliminary calibration measurements to determine device-specific parameters before actual audio playback. This advance preparation ensures synchronization is achieved while keeping the calibration process transparent and simple for users.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3755009B1Method and bluetooth device for calibrating multimedia devices
Publication Date: 2025.02.05 GOOGLE LLC
  • EP3755009B1 patent drawingFigure 1~2
  • EP3755009B1 patent drawingFigure 3~4
  • EP3755009B1 patent drawingFigure 5

AI summary

The invention relates to a method for calibrating audio delays of an audio system with wireless loudspeakers. It allows to emulate surround or 3D sound systems with spatially distributed wireless loudspeakers. The method is carried out by a multimedia device (M) and comprising: a) transmitting (S10) a first probe signal for audio playback by the loudspeaker, the first probe signal comprising a first audio pattern; b) determining (S20) a signal quality by listening to an acoustic response of the loudspeaker to the first probe signal; c) determining (S30) a second audio pattern by modifying the first audio pattern based on the signal quality; d) transmitting (S40) a second probe signal for audio playback by the loudspeaker, the second probe signal comprising a repetition of the second audio pattern; and e) determining (S50) an audio delay compensation for the loudspeaker based on a measure of an audio delay between the transmitted second probe signal and an acoustic response of the loudspeaker in response to the second probe signal.