Noise reduction has nothing to do with sound leakage. Noise reduction and sound leakage are related to some extent, but they are not exactly the same concept. Noise reduction refers to taking measures to reduce the interference of environmental noise on the target sound, so as to improve the clarity and audibility of the sound. Noise reduction is often used to eliminate environmental noise, such as using active or passive noise reduction technology in aircraft, cars, headphones and other equipment to reduce the spread and perception of noise. Sound leakage refers to the leakage phenomenon that the sound propagates to other spaces or the outside world through various sound insulation structures such as walls, floors, doors and windows when the sound propagates in the physical environment.