There are two noise reduction methods for earphones

: active noise reduction and passive noise reduction.
The active noise reduction function is to neutralize the noise by generating an inverse acoustic wave equal to the external noise through the noise reduction system, so as to achieve the effect of noise reduction. Active noise reduction earphones are equipped with noise reduction circuits that can compete with external noise. Most of them adopt a large headworn design, which can block external noise by using earplug cotton and earphone shell and other structures for the first round of sound insulation. At the same time, active noise reduction circuits and power supplies are installed in order to have sufficient space.
Passive noise reduction earphones mainly form a closed space by surrounding the ears, or use sound insulation materials such as silicone earplugs to block external noise. Because the noise is not processed by the noise reduction circuit chip, it can only block high-frequency noise, and the effect of noise reduction for low-frequency noise is not obvious.