Hearing Aid Microphone Directional Control for Self-Voice Attenuation
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Solution Overview
Problem
Hearing aid users experience an unpleasant perception of their own voice due to the occlusion effect and signal processing measures, which affect both self-voice and environmental sound, especially in conversations, leading to fluctuations in volume and dynamics.
Innovation Solution
Adjusting the preferred direction of the directional characteristic of the first directional microphone relative to the frontal direction of the user to attenuate the user's own speech signal by 6 dB to 10 dB, while minimizing the impact on background noise, and using a binaural hearing system with two directional microphones to improve signal-to-noise ratio and reduce self-voice components in the recording signal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If adaptive signal processing (AGC, compression) is used to reduce gain in frequency ranges containing user's own speech, then the user's perception of their own voice is improved, but the acoustic perception of the environment is degraded and speech reproduction becomes less realistic
Solution Approach 1:
The patent segments the audio signal processing by separating the handling of own-voice components from environmental speech components. A first speech activity detector specifically detects the user's own speech activity, while a second speech activity detector detects environmental speech. This segmentation allows independent processing: gain reduction is applied only when own-voice is detected, while environmental speech detection ensures that realistic speech reproduction is maintained when others are speaking, thus resolving the contradiction between improving own-voice perception and preserving speech reproduction quality.
Solution Approach 2:
The patent implements dynamic control of the signal processing parameters based on real-time detection of speech activity type. The system dynamically adjusts whether to apply gain reduction by comparing outputs from multiple speech activity detectors and determining the type of speech activity (own-voice vs. environmental). This dynamic adaptation allows the system to optimize own-voice perception when the user is speaking while maintaining natural speech reproduction when environmental speech is present, resolving the contradiction through context-dependent processing.
2Object-affected harmful factors
If the directional characteristic of microphones is adjusted to suppress own-voice signals, then the user's own speech signal is attenuated, but the perception of background noise and environmental sounds is affected
Solution Approach 1:
The patent applies local quality by implementing frequency-dependent and direction-dependent processing. The system uses multiple microphones with specific directional characteristics and applies selective gain reduction only in frequency ranges and spatial directions where own-voice components are dominant. Environmental sounds and background noise from other directions or frequency ranges are preserved, thus attenuating own-voice while minimizing impact on background noise perception.
Solution Approach 2:
The patent introduces speech activity detectors and signal processing intermediaries that analyze the incoming audio signals to distinguish between own-voice components and environmental sounds. These intermediaries determine the type of speech activity and control the application of gain reduction, acting as mediators that selectively suppress own-voice while preserving environmental sound quality, thus resolving the contradiction between own-voice attenuation and background noise preservation.
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 enhances the user's perception of their own voice and environmental sounds by reducing self-voice interference without significantly affecting background noise levels, providing a more pleasant and clear hearing experience in conversations.
Implementation Method 1
a first directional microphone (8), which converts sound from the environment into a first signal (44) with a spatial sensitivity which is defined by a set directional characteristic (10)
Implementation Method 2
sound waves from your own voice, which are conducted primarily via the jawbone to the ear canal through structure-borne sound transmission
Data Source
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AI summary
The invention describes a method (40) for improving a recording signal (42) in a hearing system (2) with at least one hearing aid (6), in particular a hearing aid device (4), wherein the at least one hearing aid (6) is associated with a first directional microphone (8) which has an adjustable first directional characteristic (10) with a preferred direction (12), wherein the first directional microphone (8) converts sound into a first signal (44) which is incorporated into the recording signal (42), wherein speech activity (50) of a user (1) of the hearing system (2) is monitored, and wherein, upon detection of speech activity (50) of the user (1), the preferred direction (12) of the first directional characteristic (10) is adjusted relative to a frontal direction (28) of the user (1) such that the sound sensitivity of the first directional microphone (8) in the frontal direction (28) is reduced.