Active Noise Control System for Low-Frequency Attenuation
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Solution Overview
Problem
Traditional passive noise control methods are bulky, ineffective, and expensive for reducing low-frequency noise, while existing Active Noise Control (ANC) technologies face challenges in efficiently managing low-frequency noise in noisy environments.
Innovation Solution
A noise control system incorporating a sheltering structure with embedded ANC components, including acoustic sensors and transducers, uses noise cancellation principles to create a quiet zone by generating anti-noise signals to counteract external noise, combining with passive noise reduction mechanisms for enhanced effectiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If passive noise control methods (absorptive materials, partitions, enclosures) are used, then noise attenuation is achieved, but the system becomes bulky, expensive, and ineffective at low frequencies
Solution Approach 1:
The patent replaces passive mechanical noise control structures (absorptive materials, partitions, enclosures) with an active electronic control system. The ANC system uses sensors to detect noise and electronically generates anti-noise signals to cancel unwanted sounds, eliminating the need for bulky passive structures while maintaining noise attenuation effectiveness at low frequencies
Solution Approach 2:
The patent changes the approach from passive physical barriers to active electronic signal processing. By using microphones to detect noise parameters and speakers to generate anti-noise signals with opposite phase and amplitude, the system dynamically adjusts to cancel low-frequency noise without requiring large physical structures
2Object-affected harmful factors
If passive noise control methods are used, then noise attenuation is achieved, but the system becomes expensive and complex
Solution Approach 1:
The patent replaces complex passive mechanical noise control systems with a simpler electronic active noise control system. Instead of using heavy absorptive materials and complex partitions, the system uses electronic sensors and speakers controlled by signal processing algorithms, reducing both complexity and cost while maintaining effectiveness
3Object-affected harmful factors
If traditional passive noise control measures are used for low-frequency noise, then noise reduction is attempted, but the measures are ineffective
Solution Approach 1:
The patent converts the harmful low-frequency noise into a beneficial cancellation signal. By using microphones to detect the low-frequency noise and speakers to generate anti-noise signals with opposite phase, the system transforms the problematic low-frequency sound waves into constructive interference that cancels the original noise, achieving reliable noise control where passive methods fail
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
The system effectively reduces or eliminates low-frequency noise within a controlled volume, providing a quiet and comfortable environment while being more cost-effective and compact compared to traditional passive methods.
Implementation Method 1
Active Noise Control (ANC) is a technology using noise to reduce noise. It is based on the principle of superposition of sound waves. Generally, sound is a wave, which is traveling in space. If another, second sound wave having the same amplitude but opposite phase to the first sound wave can be created, the first wave can be totally cancelled.
Data Source
AI summary
A noise control system may be configured to process one or more first noise inputs from one or more first acoustic sensors, the one or more first noise inputs representing external noise sensed at one or more respective noise sensing locations on an outer surface of a sheltering structure; to process one or more second noise inputs from one or more second acoustic sensors, the one or more second noise inputs representing residual noise at one or more respective residual noise sensing locations on an inner surface of the sheltering structure; to determine a noise control pattern based at least on the one or more first noise inputs and the one or more second noise inputs; and to generate one or more control signals to control acoustic signals generated by one or more acoustic transducers based on the noise control pattern.