I'm pretty new to DIY (18 years old, so I guess I'm pretty new to a lot of things). I have SOME experience with sealed boxes (an old pair of DIY bookshelf speakers and a sub box for my brother's car), so I think I can find myself around the woodworking pretty easily. I want to add a sub to my stereo/home theater. Essentially 50% music, 50% HT use... I'm on a budget, and would like to keep it under US$400, but I am SOMEWHAT felxible on this. The room is about 18 x 20 feet with 8 ft ceilings. Big problem (i think) is very thin carpeting on essentially concrete floors (converted basement). My current speaker setup is the JBL S-312s, the S-center, and N-26s as surrounds. Size of the sub is not a conscern... at all. Neither are looks (to an extent). No SAF here. I would like a LOT of bass. I'm not expecting to get the same levels I get in my car (2 10" drivers with 200W RMS each), but I'd like a definate marked improvement in low-end levels in here. The more the better, but not at the expense of sound quality. What I am considering is essentially the Adire Alignment box on a ported Tempest (214L tuned to 15 Hz). I was considering pairing that with the PE 250W plate amp, and getting the nessasary flared ports straight from Adire. Now, I'm totally open to suggestion. Would anyone recommend any change in this, keeping in mind my uses for it (50/50 music/ht, LOTS of bass while keeping the SQ if possible)? Keep in mind I know very little about ported boxes and have zero experience in working with them, so if you think it might be a better idea to go sealed, let me know. Basically any input is welcome, and I'm sure I'll have some more questions. Thanks in Advance.