Em I don't think that's how NC.worked Active NC headphone is those headphone that when you use them in say flight or train, it will cancel out those noise(engine sound, road friction sound) by receiving and generating the same frequency/sound to cancel out the noise in the environment,thus providing a better listening experience, but it'll require batts to work. Passive NC headphone is just normal headphone, it provide partial NC with the pads itself.