The “Noise Cancellation” button produces the noise signal from the left speaker and an anti-noise signal from the right speaker. Hold the speakers facing each other, and then click the Noise Cancellation button. Slowly move the speakers closer together and farther apart while listening to the sound. At a certain distance apart, the anti-noise waves from the right speaker will cancel the noise waves from the left speaker, resulting in a noise that sounds quieter. This principle is used by active noise cancellation systems to achieve a quieter cabin.