Audio Device Signal Paths for ANC and Hear-Through
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Solution Overview
Problem
Existing audio devices struggle to provide improved audio quality and intelligibility while accommodating changing audio conditions and user needs, particularly in environments with varying noise levels.
Innovation Solution
An audio device with separate feed-forward and feed-back noise cancellation systems, combined with a hear-through processing module, allowing for adaptive and customizable audio processing through filter controls.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If active noise cancellation is implemented, then audio quality is improved, but user awareness of surroundings deteriorates
Solution Approach 1:
The patent segments the audio processing into distinct functional modules: feed-forward noise cancellation path, feed-back noise cancellation path, and hear-through processing path. Each path operates independently with its own filters and processing, allowing selective activation based on user needs and environmental conditions.
Solution Approach 2:
The system dynamically switches between different operating modes (noise cancellation mode, hear-through mode, and hybrid mode) based on real-time audio conditions and user preferences. The filter coefficients and processing parameters are continuously adjusted to optimize performance for the current scenario.
2Manufacturing precision
If adaptive audio processing is implemented, then audio quality is improved, but device complexity increases
Solution Approach 1:
The audio processing system is divided into separate functional blocks: distributor for signal routing, feed-forward filter for ambient noise cancellation, hear-through filter for transparency mode, feed-back filter for in-ear noise cancellation, and mixers for signal combination. This modular architecture simplifies implementation and control of complex adaptive processing.
Solution Approach 2:
The patent implements feed-back noise cancellation using a microphone inside the ear canal to directly measure the residual noise after feed-forward cancellation and the output sound. This feedback path enables real-time adaptation and optimization of the cancellation algorithm, improving audio quality while maintaining manageable system complexity through closed-loop control.
3Adaptability or versatility
If multiple filter controls are provided, then adaptability is improved, but device complexity increases
Solution Approach 1:
The patent provides separate filter controls for different processing paths: feed-forward filter for ambient noise, hear-through filter for transparency mode, and feed-back filter for in-ear noise. Each filter can be independently adjusted, enabling fine-grained adaptability to different listening scenarios without requiring a single complex adaptive algorithm.
Solution Approach 2:
The distributed filter architecture enables the same hardware components to serve multiple functions: the feed-forward filter handles ambient noise cancellation, the hear-through filter enables transparency mode, and the feed-back filter provides in-ear noise cancellation. This multi-functionality achieves high adaptability while avoiding the need for separate dedicated systems for each function.
Data Source
AI summary
An audio device comprising an interface with a receiver with an output sound based on an audio output signal; a feed-forward microphone; a distributor for provision of a first feed-forward input signal and a second feed-forward input signal; a feed-back microphone; a feed-forward filter for provision of a feed-forward output signal; an intermediate filter module, wherein the intermediate filter module comprises a hear-through filter based on the second feed-forward input signal and wherein the intermediate filter module is configured to provide the intermediate signal based on the hear-through signal and the audio input signal; a first mixer for provision of an error signal based on the feed-back input signal and the intermediate signal; a feed-back filter signal based on the error signal; and a second mixer for provision of the audio output signal based on the feed-forward output signal and the feed-back output signal.