Exclusive to Essence STX II 7.1 is a multichannel daughterboard that delivers true 7.1-channel surround with high-fidelity 120dB SNR outputs. Keeping the audiophile spirit and philosophy alive Four years after the debut of Essence STX - the long-term holder of the number-one position in Head-Fi's Sound Cards segment, as voted by highly-satisfied users globally - ASUS remains committed to delivering ever better high-end sound cards to delight the most demanding audiophiles. Drawing on years of experience in developing Essence One, Essence STU and Essence III, Essence STX II delivers meticulous design, quintessential performance and profound musicality - elements that shape the spirit of the whole Essence Hi-Fi series. Impeccable headphone amplification Top-notch headphone amplifier supports The built-in headphone amplifier supports up to 600ohm impedance - so audiophiles can plug in the finest high-impedance headphones to enjoy the pure quality delivered by Essence STX II. Exquisite headphone gain control ASUS engineers have furnished Essence STX II with an additional gain control designed especially for high-sensitivity IEM headphones, allowing musicians and audio purists to use earpieces that channel audio output straight to the ear canal - isolating ambient noise for listening that requires undisturbed concentration.