In-Ear Echo Suppression via Adaptive Least Mean Squares Filtering
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Solution Overview
Problem
Earpieces often suffer from echo feedback issues due to inadequate sealing, leading to annoying 'howling' sounds that degrade voice communication and listening experiences, as ambient sounds leak into the ear canal and create feedback loops with internal microphones.
Innovation Solution
A method and device for in-ear canal echo suppression, using Ambient Sound Microphones and Ear Canal Microphones to capture and process signals, applying filtering and gain adjustments based on background noise levels and voice activity to produce a mixed signal that suppresses echoes and enhances voice clarity, employing a Least Mean Squares filter to model the inner ear-canal microphone transfer function and adapt filter coefficients accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the earpiece is not properly sealed within the ear canal, then ambient sounds can leak through into the ear canal, but this creates an echo feedback condition with the ear canal microphone and ear canal receiver that generates an annoying howling sound
Solution Approach 1:
The patent implements an active feedback control system where the ear canal microphone detects ambient sounds leaking into the ear canal, and the system generates an anti-phase signal through the ear canal receiver to cancel the leaked sounds, thereby preventing echo feedback howling while maintaining adaptability to improper sealing conditions
Solution Approach 2:
The patent introduces an intermediate processing system that includes the ear canal microphone, signal processor, and ear canal receiver as a mediator between the leaked ambient sounds and the user's ear, actively canceling the harmful sounds before they create feedback loops
2Reliability
If the earpiece provides sufficient occlusion, then it can utilize both the ambient sound microphone and the ear canal microphone to enhance the user's voice, but this may create feedback loops if sealing is inadequate
Solution Approach 1:
The system uses the ear canal microphone to detect leaked ambient sounds and implements active cancellation through the ear canal receiver, allowing the earpiece to maintain sufficient occlusion for voice enhancement while preventing feedback loops through real-time active noise control
3Ease of operation
If ambient sounds are captured and delivered to the ear canal, then the user can hear environmental sounds, but this can create echo feedback conditions that degrade voice communication quality
Solution Approach 1:
The system allows ambient sounds to be captured and delivered to the ear canal for user hearing while simultaneously using the ear canal microphone to detect leaked sounds and generating anti-phase cancellation signals, thereby maintaining ambient sound hearing capability while preventing echo feedback that would degrade voice communication quality
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
Effectively reduces echo feedback, improving voice communication quality by isolating ambient sounds and enhancing the clarity of spoken voices, allowing for full-duplex communication with proper or improper acoustic sealing, and ensuring safe sound reproduction levels.
Implementation Method 1
The electronic internal signal includes an echo of a spoken voice generated by a wearer of the earpiece. The echo in the electronic internal signal can be suppressed to produce a modified electronic internal signal containing primarily the spoken voice.
Implementation Method 2
employing a Least Mean Squares filter to model the inner ear-canal microphone transfer function and adapt filter coefficients accordingly
Implementation Method 3
An ear canal receiver mounted internal to the ear canal can loopback sound captured at the ambient sound microphone or the ear canal microphone to allow the user to listen to captured sound. If the earpiece is however not properly sealed within the ear canal, the ambient sounds can leak through into the ear canal and create an echo feedback condition with the ear canal microphone and ear canal receiver.
Data Source
AI summary
An earpiece (100) and acoustic management module (300) for in-ear canal echo suppression control suitable is provided. The earpiece can include an Ambient Sound Microphone (111) to capture ambient sound, an Ear Canal Receiver (125) to deliver audio content to an ear canal, an Ear Canal Microphone (123) configured to capture internal sound, and a processor (121) to generate a voice activity level (622) and suppress an echo of spoken voice in the electronic internal signal, and mix an electronic ambient signal with an electronic internal signal in a ratio dependent on the voice activity level and a background noise level to produce a mixed signal (323) that is delivered to the ear canal (131).