Active Noise Control System Single Microphone Adaptive Filtering
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Solution Overview
Problem
Existing active noise control systems require multiple microphones and speakers for each seat, leading to increased complexity and cost, and the noise cancellation effect is compromised when users move their heads, causing discomfort due to weakened cancellation.
Innovation Solution
An active noise control system with shared speakers and a single microphone positioned between the speakers, using adaptive filters to generate canceling sounds that account for the listening positions of users on adjacent seats, allowing for effective noise cancellation without individual microphones on each seat.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a microphone is provided for each seat to implement active noise control, then the noise cancellation effect for each user is improved, but the system complexity and cost increase
Solution Approach 1:
A single microphone is used to serve multiple seats simultaneously. The microphone captures sound signals that are then processed by auxiliary filters to create canceling sounds for multiple users, making the microphone universal rather than dedicated to each seat.
Solution Approach 2:
The patent combines the noise control functions for multiple seats into a single integrated system. Instead of separate microphone-speaker pairs for each seat, multiple noise control channels share common microphones and speakers, merging previously separate functions into a unified system.
2Reliability
If the noise cancel position is fixed for each seat, then the cancellation effect is optimized for that position, but user comfort deteriorates when users move their heads
Solution Approach 1:
The system dynamically adapts to user position changes by using auxiliary filters that account for sound propagation characteristics. When users move their heads, the auxiliary filters adjust the canceling sound signals to maintain effective cancellation across different listening positions, making the system dynamic rather than static.
Solution Approach 2:
The auxiliary filters modify the parameters of the canceling sound signals based on the intended listening positions. By adjusting frequency characteristics and phase relationships through the auxiliary filters, the system maintains cancellation effectiveness across a range of positions rather than being optimized for a single fixed point.
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 configuration simplifies the system, reduces costs, and maintains effective noise cancellation even when users move their heads, minimizing discomfort from weakened cancellation effects.
Implementation Method 1
a speaker that outputs a cancel sound that cancels noise at the noise cancel position
Data Source
Figure 1
Figure 2A~2B
Figure 3A~3B
AI summary
Provided is an "active noise control system and an in-vehicle system" to cancel noise at a plurality of seats using a single microphone (9). A first seat noise control device (3) corrects sound collected by a microphone (9) to sound at a listening position of a sound of a user seated on a first seat, generates a cancel sound that cancels, at the first seat, the sound of a second seat audio source (2) output from a second seat speaker (8) by using an adaptive filter that receives the sound of the second seat audio source (2) with the sound as an error, and outputs the cancel sound from a first seat speaker (7). A second seat noise control device (4) corrects the sound collected by the microphone (9) to sound at the listening position of the user seated on the second seat, generates a cancel sound that cancels, at the second seat, the sound of a first seat audio source (1) output from the first seat speaker (7) using an adaptive filter that receives the sound of the first seat audio source (1) with the sound as an error, and outputs the cancel sound from the second seat speaker (8).