Feeder drivers. How creative can you get?
i'll have to search some old HDs for the pics, but here's the specs on my old setup:
JVC arsenal head unit
Midland cb
Rockford Fosgate 6" spkrs
Blaupunkt 6X8 spkrs
Infinity 9" subwoofer
Blaupunkt 500W amp (for sub)
wooden enclosure, black roll-on bedliner finish, sub had it's own sealed enclosure w/polyfill, side access panel for fuse block and ground strip, built in SWR meter for cb, carrying handle and pass-thrus for seatbelt, all six speakers faced different directions, RCA input/output panel, 8 ohm cb speaker, 2 power hook-ups (standard 2 wire flat & lighter plug), weighs around 50 lbs (which is why i eventually down-sized).