Hearing Aid Subsonic Filter for Occlusion Suppression
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Solution Overview
Problem
Existing hearing aids face challenges in effectively reducing occlusion effects caused by subsonic energy from jaw motion, leading to artefacts and wasted battery energy due to high amplitude sound pressure levels, which current technologies fail to adequately address.
Innovation Solution
A hearing aid design incorporating a receiver with extended low frequency response and static pressure capability, combined with defined subsonic filtering, to improve occlusion suppression by attenuating subsonic energy without overloading the output stage and preserving dynamic range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional hearing aids amplify all frequencies including subsonic range, then low frequency hearing loss compensation is improved, but subsonic energy from jaw motion causes artefacts and wastes battery energy
Solution Approach 1:
The patent introduces a subsonic filter that selectively attenuates frequencies below a threshold (e.g., 10 Hz) while preserving the hearing aid's ability to amplify therapeutic low frequency sounds. This parameter-based frequency separation allows the system to distinguish between harmful subsonic jaw motion energy and beneficial low frequency hearing compensation signals, eliminating artefacts and conserving battery energy without compromising hearing loss compensation
2Reliability
If hearing aid housing blocks ear canal to provide amplification, then hearing loss compensation is improved, but occlusion effect causes unnatural perception of low frequency sounds and jaw sounds
Solution Approach 1:
The subsonic filter removes the frequency components responsible for the occlusion effect (below 10 Hz) while preserving the amplification of therapeutic low frequency sounds above the threshold. This creates an optimized frequency response that eliminates the unnatural perception of low frequency sounds and jaw sounds associated with occlusion, while maintaining effective hearing loss compensation
Solution Approach 2:
The patent extracts and removes the harmful subsonic frequency components from the amplified sound signal using a dedicated subsonic filter. By separating and eliminating only the problematic low frequency range below the threshold, the system removes the source of occlusion effects while preserving all beneficial amplification functions for hearing loss compensation
3Reliability
If hearing aid attempts to cancel subsonic jaw motion sounds, then occlusion suppression is improved, but high amplitude subsonic energy overloads output stage and impairs dynamic range
Solution Approach 1:
The subsonic filter is positioned in the signal path before the output amplifier and receiver, preemptively removing harmful subsonic energy before it can reach the output stage. This preliminary filtering action prevents overload conditions and dynamic range impairment, eliminating the need for complex overload protection circuits while maintaining effective occlusion suppression
Solution Approach 2:
The patent extracts and removes the harmful subsonic frequency components that cause occlusion effects before they can overload the output stage. By taking out the problematic energy in advance, the system achieves occlusion suppression without compromising the output stage or impairing the dynamic range available for therapeutic sound amplification
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 significantly reduces occlusion cancellation artefacts and conserves battery energy by effectively managing subsonic sound pressure levels, providing improved occlusion cancellation without audible artefacts or dynamic range impairment.
Implementation Method 1
a receiver with extended low frequency response or static pressure capability
Implementation Method 2
defined subsonic filtering to reduce undesirable effects due to large amounts of subsonic energy
Implementation Method 3
this sound could be emitted in opposite phase in the user's ear canal, with the effect of a perfect cancellation of the excess part of body conducted sound
Data Source
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AI summary
The present invention relates to a hearing aid which comprises an occlusion suppression system, a receiver with extended low frequency response or static pressure capability plus defined subsonic filtering to reduce undesirable effects due to large amounts of subsonic energy produced primarily by jaw motion which may exist in the frequency region below 10Hz and improve suppression of occlusion signals in a hearing aid user's ear canal.