FiiO FA7S Over-the-Ear Earphone with 6 Balanced Armature IEMs and Acoustic Prism System (Black)The hi res FiiO FA7S Earphone's expertly tuned three way crossover enables each driver in an average 1: 1: 1 way to balance the high, mid, and low frequencies, and separates them using the 2 plus 2 plus 2 method. Each frequency range takes two different drivers which are designed in an electronic and structural crossover system for precise cutting thus resulting in a more realistic, balanced sound fully capable of rendering every last detail and