Brainwavz HM9 Headphones Review - an oldie review but a goodie from the guys over at AudiophileOn! The Brainwavz HM9 headphones are crafted from a high grade and light-weight aluminum using 40 mm drivers, designed to give specific and meticulous sound quality in a high fidelity and deep bass extension – without distortion! Providing a deep and clear bass, the HM9 have a 104 dB sensitivity letting you crank your tunes to extreme loud volumes without the speakers blowing out! Get yours here