Standard headphones are designed to deliver audio. They do little to fade background distractions.

The patented Acoustic Noise Cancelling® headphone technology in Bose® QuietComfort® headphones provides full-spectrum noise reduction for a better audio experience. Microphones in the earcups actively monitor what you hear, including unwanted outside sound. The difference between the unwanted sound and the desired sound is then electronically processed, creating a correction signal that acts to negate the unwanted noise. The speaker within each earcup is then fed the correction signal. This signal, combined with the passive noise reduction of the headset itself, dramatically reduces the outside distractions that reach your ears.