Headset Self-Voice Occlusion Mitigation via Frequency Compensation

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Solution Overview

Problem

Headsets with occluding earpieces cause the wearer to perceive their own voice as unnatural due to the self-voice occlusion effect, leading to impaired communication.

Innovation Solution

A feed-forward system with a self-voice occlusion effect compensator is implemented in headsets to actively attenuate low-frequency sound pressure and amplify high-frequency sound pressure, using a block diagram with defined transfer functions to process audio signals and mitigate the occlusion effect.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If ear occluders are used to block external noise, then noise isolation is improved, but the wearer's voice perception becomes unnatural due to over-emphasized lower frequencies and under-emphasized higher frequencies

Engineering Contradiction:
Improveexternal noiseVSAvoidself-voice occlusion effect
Core Design Contradiction:
Object-affected harmful factorsVSObject-generated harmful factors

Solution Approach 1:

The patent uses the microphone to capture the wearer's voice and processes it through a filter that emphasizes high frequencies and de-emphasizes low frequencies. This inverted frequency response compensates for the occlusion effect, converting the harmful frequency distortion into a beneficial correction that restores natural voice perception.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The patent changes the frequency parameters of the wearer's voice signal by applying a filter with specific frequency response characteristics. The filter modifies the spectral distribution of the voice signal to counteract the occlusion effect's frequency distortion, thereby restoring natural sound perception.

Inventive Principle:
Principle #35Parameter changes

2Object-affected harmful factors

If ear cups or ear buds occlude the ears to provide noise reduction, then noise cancellation is improved, but communication effectiveness deteriorates due to unnatural voice perception

Engineering Contradiction:
ImprovenoiseVSAvoidcommunication effectiveness
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The system converts the harmful occlusion effect into a beneficial correction by capturing the wearer's voice with the microphone and processing it through a frequency-compensating filter. This restores natural voice perception and maintains communication effectiveness despite the occluding ear cups.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The microphone and signal processing system act as an intermediary between the wearer's voice and their own perception. The captured voice signal is processed and delivered back to the wearer through the ear cups, mediating the voice perception experience to compensate for the occlusion effect.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Object-affected harmful factors

If passive noise reduction is implemented in headsets, then noise isolation is improved, but self-voice naturalness deteriorates due to the occlusion effect

Engineering Contradiction:
Improveexternal noiseVSAvoidself-voice naturalness
Core Design Contradiction:
Object-affected harmful factorsVSEase of operation

Solution Approach 1:

The patent converts the harmful occlusion effect caused by passive noise reduction into a beneficial correction. The microphone captures the wearer's voice and the filter processes it to emphasize high frequencies and de-emphasize low frequencies, thereby compensating for the occlusion effect and restoring natural voice perception.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The system changes the frequency parameters of the voice signal by applying a compensating filter. This filter modifies the spectral characteristics of the voice signal to counteract the frequency distortion introduced by the occluding ear cups, restoring natural sound perception.

Inventive Principle:
Principle #35Parameter changes

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

The system effectively reduces the self-voice occlusion effect, allowing the wearer to hear their voice naturally with minimal delay, as demonstrated by experimental measurements showing improved sound pressure ratios and occlusion effect mitigation.

Implementation Method 1

a pair of earphones with transducers for outputting audio signals

Methodology Applied
Scientific EffectElectroacoustic transduction:

Implementation Method 2

a microphone for detecting near-end speech uttered by a wearer of the headset

Methodology Applied
Scientific EffectAcoustic transduction:

Data Source

PatentEP3213527B1Self-voice occlusion mitigation in headsets
Publication Date: 2018.07.25 BOSE CORP
  • EP3213527B1 patent drawingFigure 1A
  • EP3213527B1 patent drawingFigure 1B
  • EP3213527B1 patent drawingFigure 1C

AI summary

A device includes an ear occlude, an output transducer that is acoustically coupled to an ear canal of a wearer of the device, a voice microphone configured to generate a first electrical signal that is proportional to a voice-generated sound pressure at the microphone, and signal processing circuitry, electrically coupled to the output transducer and the microphone, including a compensator configured to generate, from the first electrical signal, a second electrical signal, and output the second electrical signal to the output transducer, wherein the compensator is tuned to cause GoE, a ratio of a sound pressure within the ear canal to a voice-generated sound pressure at a mouth reference point when the ear is occluded and electronically-aided to be approximately equal to Gu, a ratio of the sound pressure within the ear canal to the voice-generated sound pressure at the mouth reference point when the ear is unoccluded.