When you want to cut out the ambient sounds of engines, horns, and other audible nuisances, noise cancellation is king. Headphones featuring this tech carry a microphone on each earcup which picks up ambient noises, analyses them and emits a counter frequency that prevents them from reaching your ears. While it drastically improves your listening experience, it also tends to eat away quickly at battery power. This is why headphones with this feature often need bigger batteries or suffer unusually short times between charges.