Here is the quick and dirty.
Ported Designs: Use a single 6" flared Precision Port. Yes... you need either two 4" flared ports or a single 6" flared port to keep this beast from chuffing at very high SPLs.
Get the port here:
http://www.thrilleraudio.com/detail.aspx?ID=536Assuming a full length (17" long) 6" flared port you would want to build an enclosure somewhere between 240L-320L (7.8 ft^3 to 11.3 ft^3) for the high-output ported design. In any of those combinations stuff the enclosure with polyfill and use the full length 6" port. To account for the port & driver displacement subtract 10L or .36 ft^3.
The easiest way to deal with large ported box designs is to build a sonosub. As I get some time I'll post more information about building one that integrates the port design into the enclosure by nesting two tubes. It works great.... like a slot port for tubes.
Sealed Designs: These are for those people scratching their head and trying to figure out where they would fit that 11 cubic foot monster ported sub. Anything between 120-200L (4.3 ft^3 - 7 ft^3) works great. Stuff them 100% with polyfill. A 21" or 22" cube does the trick and the PE sub makes life easy.
Of course these work great as an IB sub also. No problems with doing arrays of 2, 4 or 8 units.
