Acoustic Sensor Sound-Port Attenuation for Speech Privacy

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Solution Overview

Problem

Existing hearing protection devices (HPDs) fail to adequately protect against noise-induced hearing loss (NIHL) due to limitations such as noise levels exceeding protective capabilities, bone conduction, operational requirements, and compliance issues, while monitoring systems pose privacy risks by inadvertently recording human speech.

Innovation Solution

Attenuating acoustic signals using an attenuation material covering the sound port of an acoustic sensor to suppress vocal audible ranges below the noise floor, ensuring data security and privacy while accurately monitoring acoustic or impulse events above 60 dB.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If hearing protection devices are used to protect against noise-induced hearing loss, then protection from noise exposure is provided, but noise levels exceeding protective capabilities and bone conduction bypass the HPD

Engineering Contradiction:

Improvenoise-induced hearing loss protectionVSAvoidprotective capability

Core Design Contradiction:

Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent introduces an intermediary attenuation material positioned between the sound port and the acoustic sensor. This material selectively attenuates acoustic signals in the vocal audible range while allowing high-level impulse noise to pass through, thereby mediating between the need for speech privacy and accurate noise monitoring.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The attenuation material is applied locally at the sound port area rather than throughout the entire device. This localized approach provides speech attenuation precisely where needed for privacy while maintaining the acoustic sensor's ability to detect high-level environmental noise and impulse events.

Inventive Principle:

Principle #3Local quality

2Measurement precision

If acoustic sensors monitor vocal audible ranges for noise exposure, then noise monitoring is provided, but human speech is inadvertently recorded creating privacy risks

Engineering Contradiction:

Improvenoise exposure monitoring accuracyVSAvoidprivacy risk from speech recording

Core Design Contradiction:

Measurement precisionVSObject-generated harmful factors

Solution Approach 1:

The attenuation material provides partial attenuation specifically in the vocal audible range, reducing speech signals below the noise floor while allowing excessive high-level noise signals to pass through unattenuated. This partial action approach selectively suppresses only the problematic speech frequencies without compromising overall noise monitoring capability.

Inventive Principle:

Principle #16Partial or excessive action

Solution Approach 2:

The patent converts the harmful effect of speech attenuation into a benefit by using the same attenuation material to protect privacy. The material that would normally reduce noise monitoring accuracy is instead configured to selectively attenuate only speech frequencies, thereby converting a potential harm (reduced monitoring accuracy) into a benefit (enhanced privacy protection).

Inventive Principle:

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

3Object-generated harmful factors

If attenuation material covers the sound port to suppress vocal ranges, then speech privacy is protected, but monitoring of acoustic events may be reduced

Engineering Contradiction:

Improvespeech privacy protectionVSAvoidacoustic event monitoring accuracy

Core Design Contradiction:

Object-generated harmful factorsVSMeasurement precision

Solution Approach 1:

The attenuation material's properties are specifically optimized to change the acoustic parameters selectively - attenuating mid-frequency vocal ranges while maintaining transmission of high-frequency impulse noise and low-frequency environmental sounds. This parameter-based differentiation allows simultaneous achievement of speech privacy and accurate noise monitoring.

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

Provides robust data security and privacy by suppressing audible human speech below the noise floor, allowing accurate monitoring of harmful acoustic events, thus protecting against NIHL and TBI.

Implementation Method 1

an attenuation material covering at least a portion of a first surface of an acoustic sensor... attenuating an acoustic signal received at a first surface of the attenuation material and the acoustic sensor

Methodology Applied

Scientific EffectAcoustic absorption: Acoustic Absorption

Data Source

PatentUS12424191B2Vocal acoustic attenuation

Publication Date: 2025.09.23 BLACKBOX BIOMETRICS INC

AI summary

Systems and methods to provide vocal acoustic attenuation for an acoustic sensor are disclosed, comprising attenuating an acoustic signal using an attenuation material covering at least a portion of a first surface of the acoustic sensor.