How do noise-cancelling headphones work? 

When it comes to noise reduction, the first thing that comes to your mind may be to close the doors and windows tightly so that noise can’t get in, and the room will naturally be quiet.

This is called physical noise reduction, and it is the most common noise reduction method in our lives. Wearing earplugs to sleep at night also falls into this category.

However, there are two drawbacks to physical noise reduction: First, it can significantly reduce high-frequency noise such as car whistles, but it is not so obvious to medium and low frequencies such as wind. Second: it also shields the human voice, so it is quite dangerous to use physical noise reduction methods such as earplugs when going out. 

Noise-cancelling headphones are not so primitive. It adopts the active noise reduction method: first use the microphone to collect the noise in the environment, and then use the processor to calculate a sound wave opposite to the noise to cancel the noise, so that what our ears hear is a world with almost no noise!

Noise-cancelling headphones can eliminate external noise, reducing the hearing threshold of our ears and allowing us to hear low-volume sounds. So on the subway we can also listen to low-volume ear-friendly music~ 

In addition, wearing noise-cancelling Bluetooth headphones, the world is instantly quiet, you can hear every detail in the music, and immerse yourself in the sound wave of singing. This experience is also extremely beautiful~