A great woofer for this job would have been the 2203. It is no longer available, of course, but JBL has a modern woofer which is like an improved version of the 2203-the 252G. See Giskard's graphs comparing the two in 2.5 cu. ft. boxes on this thread:

http://audioheritage.csdco.com/vbull...highlight=252g

David