i am getting my first system soon and was woundering if i have my subs connected to a amp i connect to amp to the pre outs on the HU so do i tune the HPF and LPF and SSF for the sub on the hu or are those on the amp and i set the ones on the HU for the 6 x 9s? any info on any thing related to this and tuning a systme would be great thanks thinking of getting a pioneer DEH-P480MP