Acoustical Filter for Hearing Aid Signal Attenuation
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Solution Overview
Problem
Existing acoustical modules fail to effectively attenuate self-generated signals such as acoustic and vibration signals, which interfere with the detection of external sound pressure signals, particularly in hearing devices like hearing aids.
Innovation Solution
An acoustical module with multiple microphone units and acoustical pressure pick-up points, where an acoustical filter is positioned between these points to attenuate incoming signals, and additional filters can be used to enhance suppression and reconstruct the head-related transfer function, improving signal directionality and reducing noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple microphone units and pressure pick-up points are used to detect external sound, then sound detection capability is improved, but self-generated acoustic and vibration signals interfere with detection
Solution Approach 1:
The system segments the detection function by using multiple pressure pick-up points (at least two) positioned at different locations within the hearing device. Each pick-up point captures sound pressure signals from different positions, allowing the system to differentiate between external sounds and self-generated signals through spatial analysis and signal processing
Solution Approach 2:
An acoustical filter is introduced as an intermediary element positioned between the pressure pick-up points and the signal processing path. This filter selectively attenuates specific frequency ranges associated with self-generated signals (acoustic and vibration signals from the receiver) while preserving external sound frequencies, thereby mediating between the detection need and interference reduction
2Reliability
If acoustical filters are added to attenuate self-generated signals, then signal-to-noise ratio is improved, but device complexity increases
Solution Approach 1:
The acoustical filter is implemented as a thin, flexible membrane or shell structure that can be integrated into the existing hearing device housing. This thin-film approach provides effective acoustic filtering while minimizing added complexity, volume, and structural burden on the device design
Solution Approach 2:
The acoustical filter structure is designed to serve multiple functions: it filters self-generated signals, maintains acoustic sealing, and can be integrated with the receiver assembly. This multi-functionality reduces the need for separate components and simplifies the overall device architecture despite the added filtering capability
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 module effectively suppresses self-generated signals, enhancing the signal-to-noise ratio and improving the accuracy of sound detection by minimizing the influence of internal noise sources, thereby improving the performance of hearing devices.
Implementation Method 1
an acoustical filter for attenuating an acoustical pressure signal arriving at a first acoustical pressure pick-up point relative to a second acoustical pressure pick-up point
Data Source
AI summary
An acoustical module including a receiver unit for generating audio sound, microphone units for receiving acoustical pressure signals, and acoustical pressure pick-up points. Each of the acoustical pressure pick-up points is acoustically connected to a microphone unit. The module further includes an acoustical filter for attenuating acoustical pressure signals from a first acoustical pressure pick-up point relative to a second acoustical pressure pick-up point. The invention further relates to a hearing device comprising an acoustical module.