I was doing some searching around over the weekend and stumbled on this unique JBL IMAX specification. Not sure what drivers there are using for the sub bass of x12? The crossover ranges seemed interesting and I thought Sonics was the preferred choice for the IMAX cinemas I guess I was mistaken.
http://www.science.edu.sg/ssc/otmovie.jsp?type=8&root=0&parent=0&cat=383
JBL 2202 12”
http://www.lansingheritage.org/images/jbl/specs/pro-comp/2202/page1.jpg
JBL 2240 18”
http://www.lansingheritage.org/images/jbl/specs/pro-comp/2240/page1.jpg
JBL 2240 18”
http://www.lansingheritage.org/images/jbl/specs/pro-comp/2240/page2.jpg
JBL 2245
http://www.lansingheritage.org/images/jbl/specs/pro-comp/2445/page1.jpg
IMAX
http://www.avsforum.com/avs-vb/showthread.php?t=817845