The principle of noise reduction headphones is mainly divided into three steps

The principle of noise reduction headphones is mainly divided into three steps

     The principle of noise-cancelling headphones is to use the interference of waves. Two identical sound waves hit your ears. If the crest and the crest meet, the trough and the trough meet, the volume you hear will be four times the original, because the energy of the sound is proportional to the square of the amplitude of the sound wave, and the amplitude changes. Doubled, the energy is four times the original. If the crest and trough meet, the positive and negative will cancel out. If the amplitude of the sound is 0, you will feel very quiet because the sound is completely cancelled out. Noise-canceling headphones not only have speakers, but also a microphone, which is to capture surrounding noise.

     The principle of physical noise reduction: the use of external hard materials and internal filling materials to block sound from entering the human ear can play a certain role in isolation and noise absorption.

     This physical noise reduction method is simple, common and easy to implement. It's just that physical noise reduction has an obvious shielding effect against high-frequency noise, but it seems a little helpless for mid- and low-frequency noise. In the noise range of 800 Hz or lower, physical noise reduction does not play a good role. On the other hand, physical noise-reducing headphones can block the human voice while isolating the noise from the external environment. There is a certain risk of using passive earplugs to reduce noise.

     The principle of active noise reduction headphones is mainly divided into three steps:

     Use a highly sensitive microphone as a sensor to collect and analyze external environmental noise (mainly high-frequency noise);

     Calculate the frequency of the collected noise sound waves in real time to generate a reverse sound wave. After the two sound waves at 180 degrees are combined, they cancel each other out;

     When the sound enters the human ear, the noise and the reverse sound wave cancel each other out, and the effect of noise elimination is achieved.