Acoustic Waveguide Hearing Aid Feedback Reduction
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Solution Overview
Problem
Existing hearing devices suffer from feedback, distorted sound quality, discomfort, and reduced sound localization due to inadequate coupling with the ear's vibratory structure, leading to suboptimal performance in transmitting sound while minimizing autophony and feedback.
Innovation Solution
The implementation of a hearing system with an output transducer coupled to the tympanic membrane, ossicle, or round window, and an input transducer near the ear canal opening, utilizing a sound inhibiting structure like an acoustic resistor or damper to attenuate feedback, while maintaining high frequency localization cues, and a channel configuration to manage frequency response and reduce resonance peaks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If direct mechanical coupling is used to transmit sound from transducer to eardrum, then feedback is decreased, but sound quality and spatial localization cues are degraded
Solution Approach 1:
The patent introduces an intermediary acoustic waveguide structure that couples the transducer to the eardrum through a controlled acoustic path rather than direct mechanical contact. This waveguide acts as a mediator that transmits both low frequency sound and high frequency localization cues while preventing feedback to the microphone, resolving the contradiction between feedback reduction and information preservation
Solution Approach 2:
The patent replaces direct mechanical coupling with an acoustic field-based transmission system. Instead of direct mechanical contact between transducer and eardrum, sound is transmitted through acoustic waves in a controlled medium (acoustic waveguide), which preserves spatial cues and reduces feedback while maintaining sound transmission efficiency
2Reliability
If acoustic hearing aids rely on sound pressure to transmit sound, then sound transmission is achieved, but feedback to microphone and distorted sound quality occur
Solution Approach 1:
The acoustic waveguide serves as an intermediary structure that separates the sound transmission path from the microphone, allowing sound pressure to effectively transmit audio while preventing feedback to the microphone through its physical configuration and acoustic impedance characteristics
3Object-generated harmful factors
If ear canal is sealed to inhibit sound leakage, then feedback is reduced, but autophony increases
Solution Approach 1:
The patent applies local quality by creating different acoustic conditions in different regions of the ear canal. The acoustic waveguide provides a sealed, acoustically isolated environment for sound transmission to the eardrum, while maintaining an open acoustic path for high frequency localization cues and preventing autophony through selective acoustic impedance matching at different locations
4Object-generated harmful factors
If input microphone is placed away from ear canal opening to decrease feedback, then feedback is reduced, but detection of spatial localization cues is decreased
Solution Approach 1:
The acoustic waveguide acts as an intermediary that allows the microphone to be positioned optimally for feedback reduction while still capturing spatial localization cues through the controlled acoustic path it creates, eliminating the need to compromise microphone placement
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
This configuration significantly reduces feedback, enhances sound quality, and improves user comfort by allowing natural sound transmission with preserved spatial information cues, addressing the limitations of prior hearing devices.
Implementation Method 1
a sound inhibiting structure, such as an acoustic resistor, acoustic damper, or a screen, may be positioned at a location along the ear canal between the tympanic membrane and the input transducer to inhibit feedback
Implementation Method 2
an output transducer may be coupled to a support structure, and the support structure configured to contact one or more of the tympanic membrane, an ossicle, the oval window or the round window
Implementation Method 3
An input transducer is configured for placement near an ear canal opening to receive high frequency localization cues
Data Source
AI summary
An output transducer is coupled to a support structure, and the support structure configured to contact one or more of the tympanic membrane, an ossicle, the oval window or the round window. An input transducer is configured for placement near an ear canal opening to receive high frequency localization cues. A sound inhibiting structure, such as an acoustic resistor or a screen, may be positioned at a location along the ear canal between the tympanic membrane and the input transducer to inhibit feedback. A channel can be coupled to the sound or feedback inhibiting structure to provide a desired frequency response profile of the sound or feedback inhibiting structure.