the low pass is a filter keep it all the way down and nothing but bass comes out the sub instead of bass and words, so i would keep it down as far as the rest i cant really tell you what to put it on, what i do when i set mine or my friends amps is i get them to turn it up as loud as they listen to it and i mess with it till it sounds right as far as quality and bass, i cant really tell you how you want it to sound. thats the best i can do bro