Placing a product in the “audiophile” category automatically opens it up for scrutiny of the highest order. The new Asus Xonar Essence STX “headphone amp card for audiophiles” is Asus’ latest in a line of audio card offerings that pretty much cover the spectrum of PC audio applications. Asus now offers audio cards designed for gaming to Home Theater PC applications. Today we’re looking at the latest iteration of the product, targeted at those of us with a more discerning ear–The Xonar Essence STX. The Xonar