Feedforward Window-Opening Noise Cancellation with Speaker Arrays
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Solution Overview
Problem
In office spaces with open windows for ventilation, external noise enters and disrupts the environment, necessitating a method to reduce noise levels while maintaining airflow.
Innovation Solution
A system comprising microphones and speakers arranged strategically around an opening, with a signal processor to generate output signals that cancel or reduce external noise as it enters the room, using a feedforward noise cancellation method.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If windows are opened for ventilation, then fresh air enters the room, but external noise enters the room
Solution Approach 1:
The patent introduces speakers as intermediary devices that generate anti-noise sound waves to counteract external noise entering through the open window. The microphone captures external noise, the processor generates cancellation signals, and the speakers output anti-phase sound waves that interfere destructively with the incoming noise, allowing the window to remain open for ventilation while blocking noise
Solution Approach 2:
The patent converts the harmful external noise into a useful cancellation signal by capturing it with microphones, processing it through algorithms to generate anti-phase waves, and using speakers to emit these cancellation signals. The harmful noise energy is transformed into beneficial noise-cancellation action, allowing the window to stay open while neutralizing the noise problem
2Object-affected harmful factors
If noise cancellation is implemented, then external noise is reduced, but device complexity increases
Solution Approach 1:
The patent divides the noise cancellation system into distinct functional segments: microphones for noise capture, a processor for signal generation, and speakers for anti-noise output. This segmentation allows each component to be optimized independently and simplifies the overall system architecture by separating detection, processing, and actuation functions
Solution Approach 2:
The system uses the external noise itself as the input signal for generating cancellation waves. The microphones capture the incoming noise, and the processor automatically generates the corresponding anti-phase signals without requiring external reference signals or manual calibration, making the system self-contained and reducing operational complexity
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 reduces external noise entering the room while allowing ventilation, achieving substantial noise cancellation across various room locations.
Implementation Method 1
determining one or more output signals for the set of speakers for matching, such as cancellation and/or reduction, of sound entering the room through the opening
Data Source
AI summary
A sound system and a method for noise cancellation in a room is provided, the method comprising arranging a set of microphones at a distance from an opening in a wall of the room for provision of one or more microphone input signals including a first microphone input signal; arranging a set of speakers in a vicinity of the opening; determining, based on at least the first microphone input signal, one or more output signals for the set of speakers for matching of sound entering the room through the opening; generating the one or more output signals; and outputting sound signals based on the one or more output signals with the set of speakers.