Quickly, a brief background : I'm currently using a Eden WXT500 head through a Euphonic VL110 cabinet. It's an 8 ohm, 250 watt cab that houses 10"and 5 1/4" speakers, as well as a tweeter. Anyway, my thought is to add another cab that fits underneath it, and a single 12" seemed a likely cabinet given the space requirements, and the fact that I'd like a bit more low end and to move more air. Unfortunately, my funds are limited...but I do have quite a bit of experience building guitars, basic furniture, etc...so I'm not worried about construction. What I *am* worried about is making the best cabinet for my chosen driver. The driver: Since I'm cash poor, I had to find a good bang for the buck driver that could push some low end. The Dayton PA310 is talked about as being just such a beast ! So ...speaker specs are here... http://www.parts-express.com/dayton-audio-pa310-8-12-pro-woofer--295-032 The cabinet: What I'm thinking of building is a 17.5"W x 14"H x 14.5"D cabinet. Building with 1/2" birch play for everything but the baffle, which would be 3/4", that should give a box volume of around 1.6 cubic feet. I plan on using two 3"D x 6.5"L ports, which should give it a box tuning of around 56hZ...and reduce internal volume to about 1.5 cubic feet. If I'm figuring everything correctly, the plots below "should" be correct, though I make zero claims at knowing about speaker cabinet design. Anyway, I was wondering if you see any pitfalls in the design, and/or if you have any suggestions to make it better. Please keep in mind that my funds are extremely limited, so I can't go out and buy a fEARFUL or whatever...I have to maximize what I have, given my financial situation. (Plus I like the option of using the VL110 separately for coffee house and low volume gigs) Thank you so much for any help you can provide !