Differential Sensor for Own-Voice Sensing in Hearing Aids
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Solution Overview
Problem
Hearing assistance devices face challenges in accurately detecting a user's own voice, leading to decreased sound quality and speech intelligibility due to issues like poor signal-to-noise ratio, foreign debris ingress, and discomfort from bone conduction microphones.
Innovation Solution
An in-the-ear hearing assistance device with a differential sensor mounted within a hollow plastic housing, utilizing a pressure-differential microphone that is more sensitive to bone-conducted vibrations and shielded from ambient noise and debris, enhancing speech intelligibility through its frequency response and mounting within an elastomeric sleeve.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a standard omnidirectional microphone is used in the ear canal, then the device structure is simple, but the microphone is susceptible to foreign debris and provides poor speech intelligibility
Solution Approach 1:
The microphone system is segmented into multiple functional components: a directional microphone for speech detection, an omnidirectional microphone for ambient sound, and a separate vent system. This segmentation allows each component to perform its specific function optimally while protecting the directional microphone from debris through the vent design.
Solution Approach 2:
A vent with specific acoustic properties acts as an intermediary between the external environment and the microphone system. The vent allows acoustic signals to pass through while providing a barrier against foreign debris, mediating between the need for speech detection and protection from contaminants.
2Measurement precision
If a directional microphone is positioned on a boom closer to the mouth, then own-voice detection is improved, but the device becomes susceptible to outside ambient noise and foreign debris
Solution Approach 1:
The microphone system is divided into specialized components: a directional microphone optimized for own-voice detection and an omnidirectional microphone for ambient sound capture. This segmentation allows each microphone to perform its specific function while being protected from harmful factors through the vent design.
Solution Approach 2:
The vent structure serves as an intermediary that allows acoustic signals to reach the microphones while blocking foreign debris. It mediates between the need for close proximity to the mouth for good own-voice detection and the need for protection from environmental contaminants.
3Measurement precision
If multiple transducers are used to detect different frequency portions of own-voice, then sound quality is improved, but the device complexity increases
Solution Approach 1:
The directional microphone is designed to perform multiple functions: it detects both high-frequency fricatives and low-frequency speech components with equal effectiveness. This multi-functionality eliminates the need for separate transducers for different frequency ranges, reducing device complexity while maintaining sound quality.
Solution Approach 2:
The directional microphone's frequency response is optimized through parameter changes in its acoustic design to be equally sensitive across the speech frequency range. This allows a single transducer to capture the full spectrum of own-voice effectively, avoiding the need for multiple specialized transducers.
4Measurement precision
If an ear-canal bone conduction microphone is used, then own-voice detection is improved, but it causes discomfort to the user
Solution Approach 1:
The bone conduction microphone is extracted from the ear canal and repositioned to the faceplate housing. This extraction eliminates the discomfort caused by in-canal placement while maintaining effective own-voice detection through the directional microphone's acoustic design.
Solution Approach 2:
The faceplate housing acts as an intermediary location that allows the microphone to be positioned away from the sensitive ear canal area. This intermediate position maintains functionality for own-voice detection while improving user comfort by avoiding direct contact with the ear canal.
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 provides improved speech intelligibility, protection from foreign debris, and reduced discomfort by using a single, passive pressure-differential microphone with a frequency response aligned with Speech Intelligibility Index weightings, while avoiding the need for multiple transducers or protruding elements.
Implementation Method 1
a differential sensor mounted to an interior surface of the housing in an ear canal of the wearer... The differential sensor includes inlets located within the housing and the differential sensor is configured to improve speech intelligibility of sounds from the wearer's mouth
Implementation Method 2
utilizing a pressure-differential microphone that is more sensitive to bone-conducted vibrations
Data Source
AI summary
Disclosed herein, among other things, are methods and apparatus for own-voice sensing in hearing assistance devices. One aspect of the present subject matter includes an in-the-ear (ITE) hearing assistance device adapted to process sounds, including sounds from a wearer's mouth. According to various embodiments, the device includes a hollow plastic housing adapted to be worn in the ear of the wearer and a differential sensor mounted to an interior surface of the housing in an ear canal of the wearer. The differential sensor includes inlets located within the housing and the differential sensor is configured to improve speech intelligibility of sounds from the wearer's mouth, in various embodiments.