Active Noise Reduction Principle Of Headphones

Noise reduction earphones adopt active noise control, which is different from passive sound insulation of general earphones. The principle is:
1. First, the signal microphone installed in the earphones detects low-frequency noise (100-1000Hz) in the environment that can be heard by the ears (currently up to 3000Hz)
2. Then transmit the noise signal to the control circuit for real-time operation
3. By emitting sound waves with the opposite phase and the same amplitude as the noise through Hi Fi speakers, the noise disappears and cannot be heard
Active noise reduction headphones are expensive, but generally have excellent effects and are comfortable to wear. Requires independent battery power supply, and most passive noise reduction headphones can be used without power consumption (nor active noise reduction)