Suggestions on what to do next
 

Well I've got an Alpine CDA-7875 (60x4) powering 4" Polk EX in the front and the same kind in 6 1/2" in the strut towers.

I'm just trying to figure out what to do next, like seal up the speakers I have now or not and also find out a good sub system to install.

I basically like my sound balanced, I dont want the low end frequencies to overpower the high end and vice versa. Right now it sounds great on the highs, pretty good on the mids and next to nothing lows with no sub.
Im thinking for the sub making an enclosure for the back that looks semi stock, would hold a single 10" or 12", and could be removed easily to get to the spare. Weight is also a big issue so Im wondering if I can build a box from wood then figure out a way to make a fiberglass mold so in the end, the box would be pure fiberglass.

All opinions welcome, just remember I'm fairly new with audio ;)

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