Dual-Microphone Earpiece Mixing for Background Noise Control

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Solution Overview

Problem

Existing earpiece devices face challenges in managing multiple microphones to effectively suppress background noise during voice communications and music listening, particularly in noisy environments, where noise suppressors fail to enhance the listening experience due to inadequate acoustic management.

Innovation Solution

The implementation of a method and device for acoustic management control using multiple microphones, where an Ambient Sound Microphone and an Ear Canal Microphone capture and mix signals based on background noise levels, adjusting gains and filtering to optimize audio quality, and incorporating a processor to suppress echoes and manage voice activity levels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If multiple microphones are used to capture audio signals, then noise suppression capability is improved, but device complexity increases due to lack of acoustic management control

Engineering Contradiction:

Improvenoise suppression capabilityVSAvoidacoustic management control

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The system dynamically adjusts the mixing ratio between ambient sound microphone signal and ear canal microphone signal based on detected background noise levels. When background noise is high, the system increases reliance on ear canal microphone signals; when background noise is low, it increases reliance on ambient sound microphone signals. This dynamic adaptation resolves the contradiction by automatically optimizing microphone usage without requiring complex manual acoustic management control.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system continuously monitors background noise levels and uses this feedback to adjust the signal mixing ratio in real-time. The processor detects noise characteristics and automatically modifies the gain applied to each microphone source, creating a closed-loop control system that simplifies acoustic management while maintaining effective noise suppression.

Inventive Principle:

Principle #23Feedback

2Reliability

If background noise levels increase, then noise suppression is improved by increasing internal gain, but external gain must be decreased which may reduce ambient sound quality

Engineering Contradiction:

Improvenoise suppressionVSAvoidambient sound quality

Core Design Contradiction:

ReliabilityVSLoss of information

Solution Approach 1:

The system changes the mixing ratio parameter between internal and external microphone signals based on background noise levels. When noise increases, the system increases the weight of ear canal microphone signals and decreases ambient sound microphone signals. This parameter adjustment achieves noise suppression while preserving ambient sound quality by selectively emphasizing the cleaner internal signal only when necessary.

Inventive Principle:

Principle #35Parameter changes

3Measurement precision

If frequency weighted selective mixing is applied, then signal intelligibility is improved, but processing complexity increases

Engineering Contradiction:

Improvesignal intelligibilityVSAvoidsignal processing

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The system applies different processing characteristics to different frequency ranges of the audio signals. Frequency-weighted filtering is applied selectively to enhance speech intelligibility in critical frequency bands while maintaining natural sound quality in other bands. This localized processing approach improves intelligibility without requiring complex full-spectrum processing.

Inventive Principle:

Principle #3Local quality

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 solution enhances audio quality by dynamically adjusting signal gains and filtering based on background noise, effectively reducing noise interference and improving voice communication clarity in noisy environments.

Implementation Method 1

capturing an ambient acoustic signal from at least one Ambient Sound Microphone (ASM) to produce an electronic ambient signal

Methodology Applied

Scientific EffectMicrophone transduction:

Implementation Method 2

capturing in an ear canal an internal sound from at least one Ear Canal Microphone (ECM) to produce an electronic internal signal

Methodology Applied

Scientific EffectMicrophone transduction:

Implementation Method 3

mixing the electronic ambient signal with the electronic internal signal in a ratio dependent on the background noise signal to produce a mixed signal

Methodology Applied

Scientific EffectSignal mixing and gain control:

Data Source

PatentUS20090016541A1Method and Device for Acoustic Management Control of Multiple Microphones

Publication Date: 2009.01.15 ST PORTFOLIO HLDG LLC

AI summary

An earpiece (100) and a method (640) for acoustic management of multiple microphones is provided. The method can include capturing an ambient acoustic signal from an Ambient Sound Microphone (ASM) to produce an electronic ambient signal, capturing in an ear canal an internal sound from an Ear Canal Microphone (ECM) to produce an electronic internal signal, measuring a background noise signal, and mixing the electronic ambient signal with the electronic internal signal in a ratio dependent on the background noise signal to produce a mixed signal. The mixing can adjust an internal gain of the electronic internal signal and an external gain of the electronic ambient signal based on the background noise characteristics. The mixing can account for an acoustic attenuation level and an audio content level of the earpiece. Other embodiments are provided.