The WO36 is a forgiving design and I have found most subs will work in this design but not all. On average the WO36 (36 x 36) sealed section is around 1ft^3 give or take. The ported side averages around .75ft^3 give or take. This depends on baffle placement but be warned:
"When selecting woofers for this enclosure, you can model a regular 4th order single reflex box to determine the rear (sealed) chamber. If it wants less air space than you have already built (gee you made the box first?) simple add bracing to the sealed chamber until its internal volume matches the requirement of your woofer. Do not adjust the baffle further back in the chamber to reduce its size as a short cut, or you will increase the Q of the box to well over 1.0 (boom boom)."
Steve Deckert
If you want to get technical you can use WinISD Pro (
http://www.linearteam.dk/default.aspx?pageid=winisdpro) to determine the correct chamber size (ported and sealed). Simply put the specs in for the sub you are using and model the enclosure for a fourth order BP. It is time consuming but worth to get the best results. If you need more info let me know.
HT-EXT