In the back of my camaro i made out of plywood a box to fit around the hatch motor and to connect to the top of where the gas tank is under. So it closes off that hole then i cut 2 holes for the 2 12's and it works fine i bought a couple free air subs so that the pressure doesnt really matter and it sounds great and looks great.

 

now that you've practiced your woodworking skills, make an actual sealed box out of mdf, and watch it get twice as loud, sound twice as good, and be able to handle twice the power.

which free-air speakers are you using?

 

http://www.crutchfield.com/S-vkRtNLQ...20&I=108PER121

click there its2 infinity kappa 12 inch free air subs. Its works for what i wanted, i didnt want an enclosed box i wanted to 12 inch subs to fit on that platform i made and with out a crtain pressure my dad told me to get the free air subs and i did. they need alittle bit of pressure but not like the regular sub. They look good and sound good for wjhat i need them for.

 

why dont you want a sealed box? those perfects are decent woofers, what amp are you using with them? im not for sure exactly how much but i'd guess my box weighs around 30-40 pounds, well over 100 with the woofers, but it sounds amazing. trust me, those perfects would really come alive.

 

That's an improper application for free air subs. Free air subs are designed to work in an environment where the "enclosure" is very large. You don't have that type of environment. You just have a really leaky sealed box. I'm glad that you like the sound, but a real enclosure with a set of subs designed for a sealed box will sound much, much better.

I built the same type of half assed partial enclosure when I was a teenager. I liked it at the time, but the difference between that and a real enclosure is nothing short of staggering.

If you're interested in an education, read this:
http://www.iroczone.com/technical/Subwoofer/