AKG N90Q Reference Class Auto-Calibrating Noise Cancelling Headphones - Black TruNote Technology analyzes sound pressure distribution, then it adjusts the sound according to the shape of your ear. Tone Control : Developed with inputs from Grammy winner Quincy Jones, Tone Control truly personalizes the sound you hear by allowing you to adjust bass and treble without any sound distortion. Active Noise Cancellation : Turn down distracting sounds so its just you and the music, uninterrupted. No matter what else is happening in the room, youll hear only what you want. Patented ergonomic design: Dual-density ear cushions reduce reflections inside the acoustic chamber.