Hearing Aid Receiver with Extended Low-Frequency Response
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Solution Overview
Problem
Hearing aids face challenges in effectively suppressing occlusion, particularly at low frequencies, due to limitations in existing receiver designs and venting methods, which result in reduced low-frequency gain, increased risk of acoustical feedback, and unpredictable occlusion reduction.
Innovation Solution
A hearing aid with an occlusion suppression system and a receiver featuring an extended low frequency response, where the receiver's cut-off frequency is set below 40 Hz, combined with an acoustical vent, to improve occlusion suppression and reduce artefact sounds by enhancing low-frequency sound pressure levels without overloading amplifiers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If venting methods are used to reduce occlusion, then occlusion perception is reduced, but low-frequency gain is reduced and acoustical feedback risk increases
Solution Approach 1:
The patent replaces the mechanical venting approach with an electronic signal processing system. The occlusion suppression system uses a microphone to detect ear canal sound pressure, processes this signal through a digital signal processor to generate an anti-phase occlusion signal, and combines it with the hearing loss compensation signal. This electronic substitution eliminates the need for physical vents, thereby maintaining low-frequency gain while reducing occlusion perception and preventing acoustical feedback.
Solution Approach 2:
The patent introduces an intermediary occlusion suppression system that mediates between the hearing loss compensation signal and the final output. This intermediary system processes the ear canal sound pressure signal, generates the appropriate suppression signal, and combines it with the original signal before output. This intermediary approach allows precise control of occlusion suppression without the adverse effects of venting.
2Object-affected harmful factors
If receiver cut-off frequency is lowered to improve low-frequency response, then occlusion suppression improves, but amplifier overload risk increases
Solution Approach 1:
The patent employs a feedback mechanism where a microphone in the ear canal continuously monitors the sound pressure level. This feedback signal is processed to determine the appropriate occlusion suppression signal strength, which is then combined with the hearing loss compensation signal. This closed-loop feedback system allows the receiver to operate with extended low-frequency response while automatically adjusting the suppression signal to prevent amplifier overload and maintain stability.
3Measurement precision
If complex occlusion suppression calculations are performed, then suppression accuracy improves, but processing time and computational load increase
Solution Approach 1:
The patent implements a balanced approach where the digital signal processor performs the necessary occlusion suppression calculations with adequate precision without excessive computational complexity. The system processes the ear canal sound pressure signal and generates the suppression signal with sufficient accuracy to effectively reduce occlusion perception, while optimizing the computational algorithm to avoid unnecessary processing time and computational load.
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 effectively reduces occlusion sound pressure at very low frequencies, increases maximum stable gain, and eliminates artefact sounds, improving hearing aid fits and reducing feedback loop instability.
Implementation Method 1
an ambient microphone configured to receive and convert environmental sound into an electronic input signal
Implementation Method 2
an ear canal microphone configured for converting ear canal sound pressure into an ear canal signal
Implementation Method 3
a receiver configured to receive the combined signal, and convert the combined signal into an acoustic output signal
Data Source
AI summary
A hearing aid includes an ambient microphone configured to receive and convert environmental sound into an electronic input signal, a hearing loss processor configured to process the electronic input signal in accordance with a hearing loss of a user, and generate an electronic output signal, a receiver, an ear canal microphone configured for converting ear canal sound pressure into an ear canal signal, an occlusion suppressor for reception and processing of the ear canal signal and for transmitting an occlusion suppression signal, and a signal combiner configured for combining the occlusion suppression signal and the electronic output signal to form a combined signal, and for transmitting the combined signal to the receiver, wherein the receiver is configured to receive the combined signal, and convert the combined signal into an acoustic output signal, and wherein the receiver has a frequency response with a lower cut-off frequency that is less than 40 Hz.