Active Noise Cancellation (ANC) - definition

Active Noise Cancellation (ANC) is like a smart robot in your headphones. This robot listens to the noise around you and creates an opposite sound wave to cancel out that noise. It’s like when you see a wave coming at you on the beach, and you make your own wave to stop it. But remember, this smart robot needs power to work, so headphones with ANC need to have a battery as a power source.

So, the ANC enabled earphone's actually listens to the noise generated in the environment and creates the exactly same lookalike opposite signal so that the noise can be cancelled and only send the intended audio coming from your mobile phone or computer without disturbance.
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