A sound wave is a wave of air compression and rarefaction. If you use speakers to emit a wave with the same frequency and amplitude but with inverted phase, they weaken each other. This is the operating principle of ANC (Active Noise Control) shown in Figure 1. Active Noise Control (ANC) is a technology that can significantly reduce noise levels, especially if the sound source is well localized. ANC demonstrates even better results, if the noise spectrum has periodic components.
Promwad develops scalable embedded active noise control systems for various applications.
Areas of ANC application:
- Low-noise server cabinets
- Windows and soffits
- Cars and trucks
Picture 1 — ANC principle
- The number of compensating speakers: 1–8
- The number of microphones / non-acoustic sensors: 2–16
- Frequency range: 20 Hz – 1000 Hz
- The level of periodic components attenuation: 25 dB