Microphone Matching for Wearable Directional Hearing Devices
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Solution Overview
Problem
Hearing assistance devices with multiple microphones often experience microphone mismatch, leading to degraded directional performance due to varying microphone characteristics over time and changing sound environments, which existing methods fail to reliably address.
Innovation Solution
A system that includes a first and second microphone, a digital signal processor, and a mismatch filter to detect and adaptively cancel variations in microphone reception by using the user's voice to determine a frequency profile and produce a matched directional output signal, ensuring consistent spatial positioning and reliable adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If multiple microphones are used in hearing assistance devices, then sound reception capability is improved, but microphone mismatch degrades directional performance
Solution Approach 1:
The system continuously monitors the user's voice and adjusts microphone weighting in real-time based on feedback from the voice characteristics. The processor modifies the directional filter coefficients dynamically to compensate for microphone mismatch, creating a closed-loop system that maintains directional performance despite variations in microphone response over time.
Solution Approach 2:
The system changes the parameters of the directional filters dynamically by adjusting filter coefficients based on detected voice characteristics. When voice is detected, the system modifies the frequency response and directional characteristics of the microphones through parameter adjustment, allowing the same physical microphone array to adapt to varying acoustic conditions and maintain optimal directional performance.
2Adaptability or versatility
If microphone characteristics change over time, then device adaptability is improved, but manufacturing adjustment becomes unreliable
Solution Approach 1:
The system performs self-adjustment by automatically detecting voice characteristics and modifying microphone weighting without requiring manual intervention or precise manufacturing calibration. The device monitors its own performance through voice detection and autonomously adjusts the directional filters to compensate for microphone variations, eliminating the need for precise manufacturing adjustment while maintaining adaptability.
3Ease of operation
If environmental sounds are used for microphone matching, then adjustment capability is improved, but performance degrades in varying sound environments
Solution Approach 1:
The system uses the user's own voice as an intermediary reference signal for microphone matching, rather than relying on external environmental sounds. The voice serves as a stable, controllable reference that is inherently associated with the user, providing reliable adjustment regardless of environmental conditions. This intermediary approach eliminates the variability introduced by environmental sounds while maintaining ease of automatic adjustment.
Data Source
AI summary
Method and apparatus for microphone matching for wearable directional hearing assistance devices are provided. An embodiment includes a method for matching at least a first microphone to a second microphone, using a user's voice from the user's mouth. The user's voice is processed as received by at least one microphone to determine a frequency profile associated with voice of the user. Intervals are detected where the user is speaking using the frequency profile. Variations in microphone reception between the first microphone and the second microphone are adaptively canceled during the intervals and when the first microphone and second microphone are in relatively constant spatial position with respect to the user's mouth.