I have a boss audio 7in motorized single din stereo. It has 2 pre amp outputs and a single sub out. By single I mean one plug, not a left and right like on normal stereos. How would I hook subs up to this output? I have the subs on the other outputs but I want to use the subs because it has the low filter and my father has a pioneer with the low filter and it sounds amazing. So how would I use the single sub out?