In-Ear Canal Sound Suppression via Adaptive Echo Cancellation
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Solution Overview
Problem
Earpiece devices that use both ambient sound microphones and ear canal microphones for voice communication and music listening often suffer from echo feedback issues due to incomplete sealing in the ear canal, leading to annoying howling sounds and degraded audio quality.
Innovation Solution
The implementation of an acoustic management module within the earpiece that automatically mixes signals from ambient and ear canal microphones, using adaptive filters and voice activity detection to suppress echo and isolate the user's voice, while allowing ambient sounds to be heard.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the earpiece provides sufficient occlusion to isolate ambient sounds, then voice communication quality is improved, but echo feedback occurs when the seal is incomplete
Solution Approach 1:
The system uses the ear canal microphone to detect feedback sounds and implements active feedback cancellation by generating anti-phase signals to cancel the howling echo, transforming the feedback problem into a controllable signal processing task
Solution Approach 2:
The acoustic management module acts as an intermediary between the ambient sound microphone, ear canal microphone, and ear canal receiver, processing and mixing signals to prevent echo feedback while maintaining audio quality
2Adaptability or versatility
If both ambient sound microphone and ear canal microphone are used to enhance voice, then voice communication capability is improved, but echo feedback degrades audio quality
Solution Approach 1:
The system continuously monitors the ear canal microphone signal for feedback characteristics and actively cancels detected howling frequencies by generating counter-phase signals, allowing dual-microphone operation without echo degradation
Solution Approach 2:
The acoustic management module extracts and separates the user's voice signal from the combined microphone inputs while filtering out feedback components, delivering only the enhanced voice signal to the receiver
3Ease of operation
If the ear canal receiver loops back captured sound for user listening, then audio content delivery is improved, but feedback loop generates annoying howling
Solution Approach 1:
The system implements feedback cancellation by detecting howling frequencies in the ear canal microphone signal and generating anti-phase cancellation signals to neutralize the feedback loop, enabling continuous audio delivery without howling
Solution Approach 2:
The system uses the feedback signal itself as a reference to generate cancellation signals, converting the harmful howling feedback into a useful control signal for active noise cancellation
Data Source
AI summary
A method of generating a suppression signal using an adaptive filter, using an ear canal microphone signal from an earphone and an audio content signal and combining the suppression signal with others signals to generate a mixed signal that is sent to a speaker.