The REAudio one is exactly what I want but I have to give it the port width and length which I don't have...... How do I figure this out? The other one you would give it the Frequency you want it tuned to and it would figure out port width and lentgh.

I'm sure there's a way to figure it out? I want a box that's 36" wide by 17" tall and it's for a single Fusion 12" Jonah Lomu:

fjl-1211 Jonah Lomu Woofer

* Magnet Structure 300 Oz
* Power Handling 1300 Watts
* Voice Coil 3" Black Alloy SVCImpedence (per coil) 4 Ohms
* Free Space Resonance (Fs) 28Hz
* Efficiency 89db
* Frequency Response 21Hz to 1.2kHz
* Mounting Diameter (mm) 11.22"/285mm
* Mounting Depth (mm) 6.49"/165mm