Audio Source Device Type Detection via Acoustic Echo Cancellation

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Solution Overview

Problem

Existing audio systems fail to accurately configure acoustic dosimetry processes to differentiate between headset and loudspeaker usage, leading to inadequate sound level measurements and notifications, as they do not properly account for the type of audio output device used.

Innovation Solution

An audio source device determines whether an audio output device is a headset or a loudspeaker by analyzing the microphone signal and configuring the acoustic dosimetry process accordingly, using acoustic echo cancellation and correlation analysis to differentiate between the two.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the audio source device uses a single configuration for acoustic dosimetry, then the system is simple to implement, but the sound level measurements are inaccurate for different device types

Engineering Contradiction:

Improvesound level measurement accuracyVSAvoidacoustic dosimetry configuration complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The acoustic dosimetry configuration is made dynamic by automatically adapting it based on the detected audio output device type. The system transitions from a static single configuration to a dynamic multi-configuration system that selects appropriate parameters (microphone sensitivity, measurement thresholds, notification levels) based on whether a headset or loudspeaker is detected, resolving the contradiction between measurement accuracy and system simplicity.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system changes acoustic dosimetry parameters (microphone sensitivity settings, sound level thresholds, measurement gain) according to the detected device type. By adjusting these parameters dynamically based on whether the output device is a headset or loudspeaker, the system achieves accurate measurements across different device types without requiring manual configuration for each scenario.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If the system provides hearing health notifications for all audio output, then hearing safety is maximized, but false alarms occur with loudspeakers

Engineering Contradiction:

Improvehearing health protection reliabilityVSAvoidfalse alarm rate

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The hearing health protection notifications are applied locally based on the specific audio output device type detected. The system provides detailed hearing health monitoring and notifications specifically for headsets where the microphone captures direct ear canal sound, while suppressing or modifying notifications for loudspeakers where the same microphone signal would generate false alarms. This localized application of quality control resolves the contradiction between reliability and false alarm reduction.

Inventive Principle:

Principle #3Local quality

3Measurement precision

If the audio source device performs acoustic echo cancellation to determine device type, then device differentiation accuracy is improved, but processing time increases

Engineering Contradiction:

Improvedevice type detection accuracyVSAvoidprocessing time

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The system performs preliminary acoustic echo cancellation processing during the initial connection phase or during brief silent intervals in audio playback. By conducting the device type detection process in advance or during non-critical periods, the system minimizes the impact on user-perceived processing time while still achieving accurate device differentiation through the correlation analysis of microphone signals against known echo patterns.

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

Enables accurate sound level measurements and notifications based on the type of audio output device, ensuring compliance with hearing health safety standards and minimizing the risk of hearing loss.

Implementation Method 1

driving a speaker to output a sound

Methodology Applied

Scientific EffectElectroacoustic transduction:

Implementation Method 2

The audio source device obtains a microphone signal from the microphone of the source device, where the microphone signal captures the outputted sound

Methodology Applied

Scientific EffectAcoustic transduction:

Implementation Method 3

The source device may process the microphone signal by performing an acoustic echo cancellation process upon the microphone signal using the audio output signal as a reference input, to produce a linear echo estimate

Methodology Applied

Scientific EffectAcoustic echo cancellation:

Data Source

PatentUS11456006B2System and method for determining audio output device type

Publication Date: 2022.09.27 APPLE INC

AI summary

A method performed by a processor of an audio source device. The method drives an audio output device of the audio source device to output a sound with an audio output signal. The method obtains a microphone signal from a microphone of the audio source device, the microphone signal capturing the outputted sound. The method determines whether the audio output device is a headset or a loudspeaker based on the microphone signal and configures an acoustic dosimetry process based on the determination.