I was thinking about venting my subs from my trunk, between the two 6x9's I have to both reduce distortion from the 6x9's when the subs are up (I don't hear any really, but I feel it's there in the midbass) and possibly increase spl a little.
I've only got 2 layers of dynamat on my trunk lid, still have to hit the sides and lid with a few more, but I was thinking about just cutting a hole in the rear deck between the 6x9's where there's already a square cut out from the sheet metal. Then just put some speaker grill cloth with small bracers (in case someone tosses something on my rear deck) over the hole.
I also was thinking of isolating the rear of my 6x9's with baffles, but they'd have to be big enough to not restrict the movement of the 6x9's. I've heard too small of a baffle will really cut down on the bass output because of the limited airspace.
Specs:
JVC AVX-640 HU
2 Infinity Kappa 6.5" coaxial's in front doors
2 Infinity Kappa 6x9" coaxials in rear deck
Powered by a 90Wx4 Infinity Reference amp
2 12" Rockford Fosgate P3's (cool ass '11 model with the weird dimple in the cone)
Powered by a Rockford Fosgate 1000-1bd amp
Just tryin' to get everything in check before I mount two 3.5" JL's on the a-pillars and start with some real EQ's to get everything loud, yet clean.