Built a .75 cu ft sealed enclosure for my double cab... subwoofer options

I'll be using the subwoofer channel on a Kicker CXA600.5, so about 300 watts RMS, and am debating between:

1) A pair of 8" Kicker Comp S woofers and polyfill to make up some volume. Kicker recommends .5 cu ft for each, so my enclosure is short by about .25. Would polyfill make up *that* much of a difference?

2) A single 8" Kicker Comp R without polyfill; box would be right on the money, but I'm wondering if two lesser 8" woofers would give me more volume.

Pretty set on Kicker for budget reasons (and I've always wanted to try the brand) although I briefly considered Skar, DS18, and NVX, etc. The reviews -- particularly on Skar -- threw me off. It seems like that crop of 8" high-excursion subwoofers are all coming from the same factory.

**slight update**

For those interested, my box is a simple rectangle measuring 29"x6"x10" (L/W/H) that fits behind the rear passenger-side seat (plastic storage bins removed). It tucks below the child safety restraint and runs to the metal 60/40 seat separator. My main objective was to maintain use of the restraints... seems like most boxes cover them up or require their removal.

 

I much prefer the comp r over the s. I personally would take the single comp r. Especially if it fits the volume of your box better. And it hit's the 300w rms mark as well.

 

Good, that's what I went with. Just waiting on the rest of the parts now...

 

Almost done. Just waiting for the subwoofer. Terminal cups installed today and wrapped in some OCP. Wanted to do something a little different than the usual gray carpet...not like anyone's going to see it though.

 

Terminal cups:

 

Are you sure you're not going to lose the box with that pattern? It perfectly blends into the environment!

 

Helps hide it from the wife.

 

If that actually works I'm gonna buy some cammo pajamas.

 

Funny you say that, I installed a full system (minus the sub) before my wife had ever been in my truck... She thinks its factory. Now that im adding a sub, i need to slowly adjust the sub volume each time she is in the truck till its at a normal volume.

See if we can get a group buy going...

 

Installed the LC7i and Kicker CXA600.5 five channel amp this afternoon. Still messing with the gains, but it sounds good so far. Ear-splittingly loud at max volume with zero increase in gain on the amp... still waiting on the 8" Comp R to arrive. Anxious to hear how it fills out the low end.

 

Got the Comp R installed tonight. Pretty much exactly what I was after... sub channel is set to about 1/4 gain and I'm not sure I'll need any more bass. I'll do some more testing/tuning tomorrow.

I quickly found out that my half-assed amp rack rattled like crazy, so I tore it out and screwed the amp and LOC directly into the plastic on the back of the seat. Looks good. Hope it holds up.