I've got two type r 12s, the older style type r's that are rated at 500w rms and 1500max. They are 4 ohm 12s and I have them wired at 1 ohm running them off of a Rockford fosgate t10001bd amp. I bought a pre-fabbed box just To have them in something while I figured out a permanent box for them. The pre fab box I bought is ported, each chamber has its own port and they come out in the middle of the box, the box has 1.86 cubic feet per chamber and it's tuned to 36 hz, the more I play around with different music and different settings in the deck and amp the more I realize that I hate this box. It's just not getting loud enough for me and it can't hit lows at all. Friends of mine that are into car audio and have been a lot longer then me have told me this box is junk and it's way too small and that these 12s are choking in it. Been told I need to have at least 2.25 to 2.5 cubic feet per 12 and that it would hit harder and sound louder tuned to 38-40hz. Figured I would ask if anyone here has experience with the type r 12s in different sized boxes, get some opinions on box size for them and port tune frequencys. I'm not really interested in hitting lows super well, I like the bass you can feel on the back of your neck and I've been told tuning a little higher to 38 to 40hz will do that and if the box is bigger it won't sacrifice the lows that much anyways. I just figured it should be a lot louder then it is and I'm pretty sure this box is the limiting factor right now and that it could be a lot louder with a bigger box.