Headphones are tuned on a finely calibrated, standardized fixture to meet our target sound profile – but our heads are not finely tuned, calibrated fixtures so the sound we actually hear is different from the designed curve due to variations in how the headphones fit on each of us, meaning most people do not hear the target sound of the headphone.    Harman’s TruNote auto calibration technology is a patented algorithm that calibrates the sound of the headphone to each individual by measuring the unique fit of the headphone to the user.  The system automatically adjusts the sound of the headphone, creating a personalized equalization that restores the sound of headphone to the design target. The headphone sound is automatically personalized to each individual ensuring that they hear JBL sound as we engineered it to sound = better audio