Speaker-Microphone Loopback for End-to-End Audio Latency

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Solution Overview

Problem

Existing systems lack effective methods for measuring end-to-end audio latency in wireless communication devices, which can lead to unsatisfactory user experiences in low-latency applications such as video conferencing and gaming.

Innovation Solution

A method and device are introduced to measure audio latency by playing an audio wave through a speaker and detecting its receipt at a microphone, recording detection times, and calculating latency based on the time difference, which can be communicated to another device or user interface.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If audio latency measurement methods are not implemented, then device complexity remains low, but measurement precision is insufficient for low-latency applications

Engineering Contradiction:
Improveaudio latency measurement precisionVSAvoidmeasurement system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The device performs self-measurement by playing audio through its own speaker and capturing it with its own microphone, eliminating the need for external measurement equipment or complex inter-device coordination. The device generates the test signal, captures it, and calculates latency autonomously

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

An audio signal serves as an intermediary carrier that traverses the complete audio path from speaker to microphone, enabling indirect measurement of the entire audio processing chain including wireless transmission, digital processing, and analog conversion without directly measuring each component

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If end-to-end latency cannot be measured, then device configuration remains simple, but synchronization of audio and video data deteriorates

Engineering Contradiction:
Improveend-to-end latency measurement capabilityVSAvoidlatency measurement and adjustment system
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The system measures end-to-end latency and uses this measurement to dynamically adjust audio processing parameters, creating a closed-loop feedback system that continuously optimizes synchronization. The measured latency value feeds back to the audio processing pipeline to compensate for delays

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system performs preliminary latency measurement during device setup or configuration phase, allowing applications to pre-adjust their audio processing parameters before actual use. This preliminary characterization enables proactive optimization rather than reactive correction

Inventive Principle:
Principle #10Preliminary action

3Measurement precision

If audio latency is not monitored and adjusted, then system operations remain simple, but user experience in video conferencing deteriorates

Engineering Contradiction:
Improvereal-time latency monitoring capabilityVSAvoidreal-time monitoring and adjustment system
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The system continuously monitors audio latency in real-time during operation rather than performing discrete measurements. This continuous monitoring ensures that latency variations are detected and corrected promptly, maintaining optimal performance throughout extended usage periods

Inventive Principle:
Principle #20Continuity of useful action

Solution Approach 2:

The system dynamically adjusts audio processing parameters based on real-time latency measurements, adapting to changing network conditions and device states. The latency compensation is not fixed but continuously optimized based on current system conditions

Inventive Principle:
Principle #15Dynamics

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 precise measurement and adjustment of end-to-end audio latency, facilitating better synchronization of audio and video data and allowing users to select low-latency devices for improved performance in latency-sensitive applications.

Implementation Method 1

a speaker and a microphone... playing, via the speaker, an audio wave

Methodology Applied
Scientific EffectElectroacoustic transduction:

Implementation Method 2

detecting the played audio wave as being received by a microphone

Methodology Applied
Scientific EffectAcoustic-to-electric transduction:

Data Source

PatentEP4686171A1Systems for and methods for audio latency measurement
Publication Date: 2026.01.28 AVAGO TECHNOLOGIES INTERNATIONAL SALES PTE LTD
  • EP4686171A1 patent drawingFigure 1A
  • EP4686171A1 patent drawingFigure 1B
  • EP4686171A1 patent drawingFigure 1C

AI summary

Audio latency measurement is provided. A device is configured to play, via a speaker (340), an audio wave in storage accessible by the device. The device is configured to detect the played audio wave by a microphone (344), the device to identify a time of detection of the audio wave. The device is configured to play, via the speaker (340), the played audio wave received by the microphone (344). The device is configured to detect the second played audio wave as being received by the microphone (344), the device to identify a second detection of the audio wave. The device is configured to determine a latency of communications of the device based on a difference between the first detection of the played audio wave and the second detection of the second played audio wave. The device is configured to communicate the latency to one of a second device or a user interface (310, 332).