Hearing Protection Earmuff Circuit for Safe Audio Amplification

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Solution Overview

Problem

Safety hearing protection devices with integrated speakers face the challenge of protecting users from external noise while preventing the speakers from causing hearing damage, and they often amplify unwanted background sounds when amplifying lower decibel sounds.

Innovation Solution

A method and device that detect external sound decibel levels and frequencies, allowing safe sounds to be transmitted or amplified while blocking or filtering out higher sounds and unwanted background noise, using external microphones and internal speakers with circuitry to manage sound levels and frequencies.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If speakers are included in hearing protection earcups for communication and entertainment functions, then user communication and entertainment capabilities are improved, but the risk of causing hearing damage increases

Engineering Contradiction:

Improvecommunication and entertainment functionalityVSAvoidhearing damage risk from speaker output

Core Design Contradiction:

Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The system dynamically adjusts speaker output based on real-time detection of external noise levels. The circuitry monitors the acoustic environment and automatically modulates speaker volume to maintain safe listening levels while preserving communication functionality, resolving the contradiction between versatility and hearing protection

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system incorporates feedback through microphones that continuously monitor the acoustic environment and feed this information to the circuitry, which then adjusts speaker output accordingly. This closed-loop control ensures that speaker volume remains safe while maintaining communication capabilities

Inventive Principle:

Principle #23Feedback

2Measurement precision

If sounds are amplified to reach desired decibel levels, then audio clarity is improved, but unwanted background sounds are also amplified

Engineering Contradiction:

Improveaudio clarityVSAvoidamplification of unwanted background sounds

Core Design Contradiction:

Measurement precisionVSObject-generated harmful factors

Solution Approach 1:

The system applies different processing qualities to different frequency ranges. It amplifies sounds within a specific frequency band of interest while filtering out unwanted background sounds at other frequencies, achieving selective amplification that maintains audio clarity without amplifying harmful background noise

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The circuitry changes the frequency parameters of the audio signal by filtering and selectively amplifying specific frequency ranges. This parameter modification allows the system to enhance desired audio while suppressing unwanted background sounds through frequency-based differentiation

Inventive Principle:

Principle #35Parameter changes

3Object-affected harmful factors

If passive noise reduction is maintained to protect from external noise, then hearing protection is improved, but speaker output capability is limited

Engineering Contradiction:

Improveprotection from external noiseVSAvoidspeaker output capability

Core Design Contradiction:

Object-affected harmful factorsVSPower

Solution Approach 1:

The system dynamically balances passive noise reduction with active speaker output by monitoring external noise levels and adjusting speaker volume accordingly. When external noise is high, the system maintains passive protection; when external noise is low, the system enables speaker output, resolving the contradiction between protection and capability

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

Ensures user safety by limiting speaker output to safe decibel levels and reducing or filtering out undesirable background sounds, maintaining effective passive noise reduction while allowing safe amplification of lower decibel sounds.

Implementation Method 1

one or more external microphones operable to pick up external sounds

Methodology Applied

Scientific EffectMicrophone transduction:

Implementation Method 2

one or more internal speaker located within the earcup operable to direct sound into a user's ear

Methodology Applied

Scientific EffectElectroacoustic conversion:

Implementation Method 3

a passive protection earcup comprising a hollow shell operable to encompass the ear of a user and having an air space volume to provide sufficient noise reduction rating (NRR)

Methodology Applied

Scientific EffectAcoustic absorption: Acoustic Absorption

Data Source

PatentUS9636260B2Custom microphones circuit, or listening circuit

Publication Date: 2017.05.02 HONEYWELL SAFETY PRODUCTS USA INC

AI summary

Embodiments of the disclosure include hearing protection earmuffs, which generally might have two earcups providing passive noise reduction (e.g. an effective NRR to protect a user from a damaging external noise environment). Disclosed embodiments include systems and methods for transmitting external sounds to a speaker within the earcup, blocking transmission of sounds that are higher than a hearing protection threshold, amplifying sounds that are below the hearing protection threshold, and reducing or filtering undesirable background sounds by determining the frequency of the transmitted sounds.