Noise Cancellation is a modern technology which actively calls off ambient sound occurring outside your headphones. find more about this is actually done using a mic installed in the earpiece that notes the ambient sounds, creates a contrary waveform sign, and plays it back via the ear piece. This cancels the ambient audio listened to by the audience and leaves behind only the audio that is actually indicated to become listened to with the earbuds, like songs from your iPod, Learn More.