The name of this type of headphone says almost everything. This is a headphone that, in addition to being able to play music naturally, can also sort the noise from the outside, so that you have full enjoyment of whatever you listen to. This type of headphone comes in many different forms, both in-ear, over-ear and around-ear, with the latter mentioned often being the solution that works best.
On many noise-canceling headphones, it is possible to turn on / off the noise-canceling function if, for example, you are in a quiet area, or yet want to hear what is happening around one. The active noise reduction requires power to operate. Therefore, noise-canceling headphones also often have built-in batteries, or the option to switch themselves (AA or AAA) for the function to work.
The audio signature is comparable to normal around-ear, on-ear, or in-ear headphones, as the speaker units used are often the same - just a little extra has been added to make noise reduction possible.