The key is how to get the noise canceling sound.

The three noise reduction measures commonly used to reduce noise, namely, noise reduction at the sound source, noise reduction during transmission and noise reduction at the human ear, are all passive. In order to actively eliminate noise, people invented the technology of "active noise elimination". Its principle is that all sounds heard are sound waves, which have a certain spectrum composition. If a sound wave can be found, its frequency spectrum is equal to the noise amplitude to be eliminated, and its phase is just opposite (difference is 180 °), the noise can be completely eliminated by superposition of the two. The key is how to get the noise canceling sound. The actual method is: start from the noise itself, monitor the noise with a microphone, and then try to generate a reverse sound wave through the electronic circuit and play it through the loudspeaker. From this point of view, the technology of active noise reduction is actually "fighting poison with poison".
When dealing with complex noise environment, the two MEMS microphones of "active noise reduction" will respectively pick up intra ear noise and various external environmental noise, equipped with an independent intelligent high-definition noise reduction processor, which can perform high-speed calculation on different noises picked up, and accurately eliminate noise. In addition, according to the noise reduction requirements of different scenes, the headset provides multiple listening modes: strong and weak active noise reduction mode and an ambient sound mode. Isolate external noise to varying degrees and eliminate the "black hole feeling" when listening to common noise reduction earphones.