Binaural Hearing Aid Feedback Reduction via Cross-Device Signal Routing

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Solution Overview

Problem

Conventional hearing aid systems inadequately address feedback issues due to the close proximity of microphones and receivers, leading to unwanted sound transmission and whistling.

Innovation Solution

The method involves separating the signal paths between microphones and receivers in a binaural hearing aid system by transmitting audio signals from one hearing aid device to the other, effectively increasing the distance between the microphone and receiver, thereby reducing feedback. This is achieved through wireless or wired signal transmission, with the option to cross-transmit specific frequency ranges or channels, particularly during high amplification or high sound pressure levels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the microphone and receiver are placed close together in a hearing aid device, then the device size is reduced, but feedback and whistling occur

Engineering Contradiction:
Improvehearing aid device sizeVSAvoidfeedback and whistling
Core Design Contradiction:
Volume of moving objectVSObject-generated harmful factors

Solution Approach 1:

The patent divides the hearing aid system into two separate devices (first and second hearing aid devices), placing the microphone in one device and the receiver in the other. This segmentation physically separates the acoustic path, preventing feedback while maintaining compact individual device sizes. The signal is transmitted wirelessly between the two devices, achieving feedback elimination without compromising miniaturization.

Inventive Principle:
Principle #1Segmentation

2Power

If high amplification is applied to compensate for severe hearing loss, then hearing ability is improved, but feedback and whistling increase

Engineering Contradiction:
Improveamplification levelVSAvoidfeedback and whistling
Core Design Contradiction:
PowerVSObject-generated harmful factors

Solution Approach 1:

The patent introduces a wireless signal transmission system as an intermediary between the microphone and receiver. The audio signal captured by the microphone is transmitted to the other hearing aid device, effectively creating a long acoustic path through the user's head. This intermediary transmission path allows high amplification to be applied without creating feedback, as the signal does not loop back through the same device.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Object-generated harmful factors

If directional microphones are used to reduce feedback, then feedback is reduced, but directional characteristics limit natural sound perception

Engineering Contradiction:
Improvefeedback reductionVSAvoidsound perception flexibility
Core Design Contradiction:
Object-generated harmful factorsVSAdaptability or versatility

Solution Approach 1:

Instead of using directional microphones to block feedback paths, the patent inverts the approach by using omnidirectional microphones that capture sound from all directions and transmitting the signal to the other ear. This inversion allows natural sound perception to be maintained while eliminating feedback through the cross-device transmission path, achieving both feedback reduction and versatile sound perception.

Inventive Principle:
Principle #13The other way round (Inversion)

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 approach significantly reduces feedback by increasing the distance between the microphone and receiver, improving wearing comfort and reducing the occurrence of whistling, especially in severe hearing loss cases, where high amplification is required, and allows the human brain to adapt to the signal interchanging, making it less disturbing over time.

Implementation Method 1

each having at least one microphone for recording an acoustic input signal and converting it into a audio signal

Methodology Applied
Scientific EffectAcoustic to electrical conversion:

Implementation Method 2

an output converter for converting a processed audio signal into a signal that the user can perceive as an acoustic signal

Methodology Applied
Scientific EffectElectrical to acoustic conversion:

Data Source

PatentEP1771038B2Method for operating a hearing-aid system for binaural treatment of a user
Publication Date: 2013.02.27 SIEMENS AUDIOLOGISCHE TECHNIK GMBH
  • EP1771038B2 patent drawingFigure 1
  • EP1771038B2 patent drawingFigure 2

AI summary

The system has first and second hearing aids (1,1') for the left and right ears of the user, each with a microphone (2,2'), a signal processor (3,3'; 4,4') and an output transducer and an arrangement for transferring an audio signal between hearing aid. At least for a defined frequency range the acoustic output signal output by the earpiece (5,5') of the second hearing aid originates exclusively from the first audio signal and the acoustic output signal output by the earpiece of the first hearing aid originates exclusively from the second audio signal. An independent claim is also included for (A) an arrangement for implementing the inventive method (B) and a method of.