I just "attempted " to set my subsonic and low pass filter today. It sucks that hifonics didn't make more marks for.setting these (quarter marks would have been good atleast) but I tried to set them as good as I could. What I read on here is, set the subsonic to where you want the lowest hrz to play and set the lowpass to where you don't want it play above a certain hrz. For me for example my box is tuned to 32 hrz so I set it where it wont play anything below 27 hrz and it.won't play anything above 80 hrz. Hope this helps.
Maybe someone can.correct me if.im wrong.
Ps. Sorry.for all the.periods. im.on mobile :/