Adaptive Hearing Protector Band Pass Filter

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Solution Overview

Problem

Wearing hearing protection in loud environments makes it difficult for users to hear important noises like conversations or commands from others, as existing technologies fail to effectively filter out undesirable sounds while allowing desirable sounds to be audible.

Innovation Solution

A hearing protection headset equipped with microphones and a processor that applies a band pass filter based on sound amplitude, selectively amplifying human voice frequencies and suppressing impulse noises, ensuring the user can hear important sounds while reducing loud background noise.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If hearing protection is worn to reduce loud noises, then noise reduction is improved, but the ability to hear desirable sounds like conversations deteriorates

Engineering Contradiction:

Improveloud noise reductionVSAvoiddesirable sound information

Core Design Contradiction:

Object-affected harmful factorsVSLoss of information

Solution Approach 1:

The audio spectrum is segmented into multiple frequency bands using several band pass filters with different center frequencies and bandwidths. This allows selective processing of different frequency ranges - attenuating harmful loud noises in certain bands while preserving desirable sounds like human voices in other bands, thereby resolving the contradiction between noise reduction and sound intelligibility

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different frequency bands are assigned different processing qualities - some bands are heavily attenuated while others are preserved or enhanced. The system applies local quality control by selectively applying gain and filtering to specific frequency ranges based on the detected noise characteristics, allowing the user to hear desirable sounds while blocking harmful noises

Inventive Principle:

Principle #3Local quality

2Device complexity

If a fixed band pass filter is used, then the filter design is simple, but it cannot adapt to varying noise levels and environments

Engineering Contradiction:

Improvefilter design simplicityVSAvoidnoise level adaptation

Core Design Contradiction:

Device complexityVSAdaptability or versatility

Solution Approach 1:

The system transitions from a static fixed filter to a dynamic adaptive filter configuration. The processor continuously monitors the audio input and automatically adjusts which band pass filters are applied and their respective gain values based on the detected noise characteristics and environment, enabling the system to adapt to varying noise levels while maintaining reasonable complexity

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system changes filter parameters dynamically - specifically the gain values and which filters are activated - based on the detected noise level and type. This parameter adaptation allows the same hardware to effectively handle different noise environments without requiring complex manual intervention, balancing adaptability with system simplicity

Inventive Principle:

Principle #35Parameter changes

3Object-affected harmful factors

If impulse noise is suppressed for an extended period, then impulse noise reduction is improved, but the suppression period may mask subsequent important sounds

Engineering Contradiction:

Improveimpulse noise reductionVSAvoidsubsequent sound information

Core Design Contradiction:

Object-affected harmful factorsVSLoss of information

Solution Approach 1:

The system uses feedback from continuous audio monitoring to dynamically control the suppression duration. After detecting an impulse noise, the processor sets a suppression period but continuously monitors the audio input during and after suppression. If important sounds are detected during the suppression window, the system adjusts the suppression timing or intensity, using feedback to prevent information loss while maintaining impulse noise reduction

Inventive Principle:

Principle #23Feedback

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 solution allows users to clearly hear human voices and commands in noisy environments by filtering out undesirable sounds, enhancing speech intelligibility and reducing background noise, thereby improving communication in loud settings.

Implementation Method 1

a microphone disposed on the apparatus and configured to pick up an input sound wave from the environment and convert the input sound wave to an incoming signal

Methodology Applied

Scientific EffectTransduction:

Implementation Method 2

a processor configured to apply a band pass filter to the incoming signal wherein frequencies of an output signal of the band pass filter vary depending on an amplitude of the incoming signal

Methodology Applied

Scientific EffectFrequency filtering: Filter (electronic)

Implementation Method 3

a speaker disposed on the apparatus, the speaker configured to produce the output from the processor

Methodology Applied

Scientific EffectTransduction:

Data Source

PatentUS9628897B2Adaptive frequency response, adaptive automatic level control and handling radio communications for a hearing protector

Publication Date: 2017.04.18 3M INNOVATIVE PROPERTIES CO

AI summary

An hearing protection device is provided. The hearing protection device can include a speaker to relay sounds, such as conversations, to the user of the hearing protection. The hearing protection device can include an electronics package that can filter out undesirable sounds, such as to improve the user's ability to hear conversations around them while still protecting the user's ears.