These are the drawings for a 10" sub enclosure I used to have in my '85 Firebird SE and '91 Firebirds. It's a sealed design and has about 1 cubic foot of volume. I used a Dynaudio Variovent to give aperiodic damping to a now 17 year old Pyle Driver subwoofer I had at the time. I was amazed at how hard this setup would hit. People couldn't believe it when I would show them that I only had a single 10" sub in back. You're welcome to use these drawings if you'd like.
http://images.cardomain.com/installs...32_98_full.jpg