Noise cancellation of headphones can be divided into passive noise isolation and active noise cancelling. Passive noise isolation adopts physical ways to isolate noise. Active noise cancelling refers to generate reverse sound waves with noise cancelling algorithm to cancel external noise after collecting ambient noise.

Passive Noise Isolation

Noise isolating earphones and headphones inherently block out ambient noise, without the use of batteries. Adjustable-fit ear tips on earphones and extra ear cup padding on headphones act as physical barriers to keep unwanted noise from reaching your ears. These barriers also help prevent people around you from hearing your music.

Active Noise Cancellation

In order to reduce the noise that can not be processed by passive noise isolation, the signal microphone placed in the earphone first detects the low frequency noise in the environment, and then transmits the noise signal to the control circuit. The control circuit performs real-time operation and then transmits acoustic waves of same noise amplitude and opposite to noise phase through the headphone to cancel noise .

Active noise cancelling requires independent battery power and can be turned on/off manually when in use.