In-Ear Echo Suppression via Adaptive Ambient Mixing
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Solution Overview
Problem
Echo feedback conditions occur when earpieces are not properly sealed, leading to annoying 'howling' sounds that degrade voice communication and listening experiences by allowing ambient sounds to leak into the ear canal and create feedback loops with ear canal microphones.
Innovation Solution
A method and device for in-ear canal echo suppression, which involves capturing ambient and internal sound signals, measuring background noise, and mixing them based on noise levels and voice activity to suppress echoes, using a processor and filters to adapt and adjust gains, and employing a Least Mean Squares (LMS) filter to model the ear-canal microphone transfer function.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the earpiece is not properly sealed within the ear canal, then ambient sounds can be blocked from entering the ear canal, but this creates an echo feedback condition that generates annoying howling sound
Solution Approach 1:
The patent implements an echo feedback suppression system that detects feedback conditions using the ear canal microphone and actively suppresses the echo by adjusting the ambient sound signal. The system monitors the feedback loop between the ear canal receiver and microphone, and dynamically controls the mixing ratio to prevent howling while maintaining ambient sound blocking.
Solution Approach 2:
The patent uses dynamic gain control and adaptive mixing ratios that adjust in real-time based on detected sound levels and feedback conditions. The system transitions between different operating states (ambient sound mode, voice enhancement mode, echo suppression mode) to optimally balance ambient sound blocking and echo prevention.
2Reliability
If the earpiece provides sufficient occlusion to block ambient sounds, then voice communication quality improves, but echo feedback occurs when the earpiece is not properly sealed
Solution Approach 1:
The system uses the ear canal microphone to detect feedback conditions and implements active echo suppression by adjusting the ambient sound signal sent to the ear canal receiver. This feedback loop allows the system to maintain reliable voice communication while preventing echo howling through real-time signal adjustment.
Solution Approach 2:
The patent dynamically changes signal processing parameters including gain levels, mixing ratios, and filter characteristics based on detected sound conditions. By adjusting these parameters in real-time, the system maintains optimal voice communication quality while preventing echo feedback across different sealing conditions.
3Adaptability or versatility
If ambient sound microphone captures ambient sounds including user voice, then environmental sounds are available for playback, but echo feedback degrades the listening experience
Solution Approach 1:
The system implements feedback suppression that specifically targets the echo path while preserving the useful ambient sound capture function. The ear canal microphone detects the feedback loop, and the system selectively suppresses only the problematic echo components while maintaining the ambient sound mixing capability for enhanced listening experience.
Solution Approach 2:
The patent applies different processing characteristics to different signal components - ambient sounds captured by the ambient microphone are processed differently from the echo feedback path detected by the ear canal microphone. This allows selective suppression of harmful echoes while preserving the versatility of ambient sound capture and playback.
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 suppresses echoes, enhancing voice communication quality by isolating ambient sounds and maintaining clear audio delivery, even in noisy environments, while ensuring safe sound reproduction levels and acoustic management.
Implementation Method 1
The echo suppressor can contain two sets of filter coefficients; a first set that adapts when voice is not present and becomes fixed when voice is present, and a second set that adapts when the first set is fixed.
Implementation Method 2
employing a Least Mean Squares (LMS) filter to model the ear-canal microphone transfer function
Implementation Method 3
A voice activity detector can adapt a first set of filter coefficients of the echo suppressor to model an inner ear-canal microphone transfer function (ECTF), and freeze an adaptation of the first set of filter coefficients for the modified electronic internal signal if the voice activity level is above a predetermined threshold.
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).