Adaptive Speaker Selection for Active Noise Control

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Solution Overview

Problem

Existing active noise control systems face challenges in adaptively selecting the most suitable speakers to effectively cancel undesired sound waves due to changing source locations and characteristics over time, leading to suboptimal noise cancellation.

Innovation Solution

An active noise control system that includes learning algorithm units and adaptive filters, which select and simulate the performance of different speaker combinations to determine the most effective set of speakers for generating anti-noise sound waves based on error signals and sound wave propagation directions, allowing for dynamic adjustment and optimization of speaker usage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a fixed number of speakers are used to generate anti-noise, then the system structure is simple, but the noise cancellation effectiveness deteriorates when source location and characteristics change

Engineering Contradiction:
Improveadaptability to changing sound sourcesVSAvoidspeaker selection mechanism complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The system dynamically adjusts the speaker configuration by switching between different speaker combinations based on real-time analysis of sound source characteristics. The adaptive filter continuously evaluates which speakers are most effective for current noise conditions and reconfigures the active speaker set accordingly, transforming a static system into a dynamic one that adapts to changing environmental conditions.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes operational parameters by adjusting which speakers are active and how they are configured based on the characteristics of the undesired sound. The adaptive filter modifies speaker selection and weighting parameters in response to varying sound source locations, frequencies, and intensities, optimizing noise cancellation for different acoustic scenarios.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If more speakers are used to generate anti-noise, then the noise cancellation effectiveness improves, but the energy consumption and system complexity increase

Engineering Contradiction:
Improvenoise cancellation effectivenessVSAvoidspeaker energy consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The system applies partial action by activating only the subset of speakers that are most effective for the current noise condition rather than using all available speakers continuously. The adaptive filter identifies and activates only the necessary speakers based on real-time acoustic analysis, reducing energy consumption while maintaining or improving noise cancellation effectiveness through targeted speaker utilization.

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The system performs self-optimization by automatically evaluating which speakers should be active based on real-time acoustic measurements and performance feedback. The adaptive filter continuously monitors noise cancellation effectiveness and autonomously reconfigures the speaker arrangement, eliminating the need for manual intervention and ensuring optimal energy utilization.

Inventive Principle:
Principle #25Self-service

3Adaptability or versatility

If speakers are frequently switched to adapt to changing sound sources, then the adaptability improves, but the system stability deteriorates

Engineering Contradiction:
Improveresponse to changing sound conditionsVSAvoidspeaker configuration stability
Core Design Contradiction:
Adaptability or versatilityVSStability of the object's composition

Solution Approach 1:

The system implements periodic evaluation and switching of speaker configurations rather than continuous changes. The adaptive filter periodically assesses whether a speaker reconfiguration is warranted based on significant changes in sound source characteristics, providing stable operation during normal conditions while enabling adaptation when necessary. This periodic action prevents excessive switching while maintaining responsiveness to meaningful environmental changes.

Inventive Principle:
Principle #19Periodic action

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 approach enables more accurate and efficient cancellation of undesired sound waves by dynamically selecting the best speaker combinations, leading to improved noise reduction in quiet zones, even as sound sources change.

Implementation Method 1

generate sound waves or 'anti noise' that destructively interferes with undesired sound waves

Methodology Applied
Scientific EffectDestructive interference: Interference

Implementation Method 2

produce destructively interfering sound waves through at least one speaker

Methodology Applied
Scientific EffectSound wave propagation: Sound

Data Source

PatentEP2251860B1System and Method for Active Noise Control with Adaptive Speaker Selection
Publication Date: 2014.09.24 HARMAN INT IND INC
  • EP2251860B1 patent drawingFigure 1
  • EP2251860B1 patent drawingFigure 2
  • EP2251860B1 patent drawingFigure 3

AI summary

An active noise control system generates an anti-noise signal to drive a first speaker group including at least one speaker to produce sound waves to destructively interfere with an undesired sound in at least one quiet zone. The active noise control system receives error signals representative of a combination of undesired sound and destructively interfering sound waves produced by the first speaker group. The active noise control system may select a second speaker group to replace the first speaker group based on the error signals.