Active Vs. Passive Noise Control
Noise control is an active or passive means of reducing sound emissions, often incentivised by personal comfort, environmental considerations or legal compliance. Active noise control is sound reduction that utilizes a power source. Passive noise control is sound reduction by noise-isolating materials such as insulation, sound-absorbing tiles, or a muffler rather than a power source.
Active noise canceling is best suited for low frequencies. For higher frequencies, the spacing requirements for free space and zone of silence techniques become prohibitive. In acoustic cavity and duct based systems, the number of modes grows rapidly with increasing frequency, which quickly makes active noise control techniques unmanageable. Passive treatments become more effective at higher frequencies and often provide an adequate solution without the need for active control.
Advantages of active noise control
- More effective at low frequencies.
- Less bulky.
- Able to block noise selectively.
Advantages of passive noise control
- More effective above 2000 Hz
- Does not require a power source
- Generally cheaper to implement
Read more about this topic: Active Noise Control
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