ANC Introduction
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What is Active Noise Control (ANC)?
- 01 "Destructive interference" is a noise reduction technology of generating a sound that has the same amplitude as the unwanted noise but the opposite phase to it and effectively canceling it out by using the principles of acoustics.
- 02 The first patent utilizing the "destructive interference effect" was applied for in 1937 by Paul Lueg, and its fundamental principles are the same as those of today's active noise control technology.
- 03 Reasons why Active Noise Control technology is not widely applied to this day
- The lack of advanced technology, such as high-performance CPUs, to implement the "destructive interference effect."
- In terms of blocking signals, the 'nasty' characteristics of sound, which can refract and diffract easily and can pass through most objects with minimal attenuation due to its relatively low frequency, make it very difficult to eliminate signals.
Active Noise Control vs. Passive Noise Control
- 01 Passive Noise Control
- Uses barrier materials like soundproofing materials
- Advantages: Effective for high-frequency noise control, simple, and cost-effective
- Disadvantages: Difficult to control low-frequency noise, increases weight due to barrier materials, and barrier materials may block things other than noise (e.g., airflow in ducts)
- 02 Active Noise Control
- Uses an electro-acoustic technique
- Advantages: Effective for low-frequency noise control, Not block anything other than noise
- Disadvantages: Difficult to control high-frequency noise, complex and expensive, and a limited control area (Quiet Zone)