home sub enclosure under the home

[mavric]

I tore it down, I am buildoing a basic bandpass box using the floor opening as the port, kinda like a fifth order band pass as I only need 30-80hz. Any suggestions? I wish I could draw a schematic of my idea, so can someone please toss me a rope?
back chamber sealed for one 12" sub, the front and vent is what I have to work on. Just trying to bass in the house in a 10"by 12" cut out in the floor, also trying to avoid air tirbulance, like I said, I have a HUGE crawl space a 1000+ cuu ft of living space. I wish I could afford some of the projects you have. I am just on the more "more space , more bass, efficent amp and sub. so enclosure volume is no big deal. I know T/s paramater does matter, however, I do not have them. the amp does 250rms and the sub is a Rockford Fosgate HE series 12 single 4ohm, it is old but never used.I love to learn, just not that famalier with a band pass F1 and F2 , maybe an adjustable vent untill I get the desired sound. Have plenty of tools, so is anyone game? Advice or pics? Mavric