ok my friend has a pioneer headunit and 3 jl w3 with a 500/1 amp... he has a serious noise problem/system tuning problem... first the noise how do you eliminate that popping noise whenever you change a station or skip to a next track on a cd... i think his headunit has 1 pair of preouts which is probably not optimized for a subwoofer.. and next its soo complicated to adjust his system cause i was trying to tune it so i can adjust it so that the front speakers only play instead of the back but here's what happens it takes off the sub when u move the fading towards the front..its acting like the sub is another fullrange speaker..i think thats just in the headunits case though... but he should be getting a new one soon that supports front,rear and sub...so the sub can have its own control...