need plan for 2x18 rcf lf18x451

 

Where did you pick up the 12 drivers from? There are a lot of fakes floating around (surprising but true). If it's from Audio plus, or any of their authorised dealers, you should have the certificate of authenticity in the box + the hologram stickers on the drivers to match with the sticker on the certificate.

 

If the drivers are genuine and if you want to go in for a reflex design, a duel enclosure with a net volume of 9.75 cuft and a Fb of 37 Hz should give you a fairly linear response. Make sure the ports are huge because these drivers can push out a large amount of air.  The carpenter's skills will be put to the test because these drivers, with proper amplification can do considerable damage to the enclousure.

 

One more point I must mention, you need very good amplifiers to get the best out of these drivers. These drivers are inherently inefficent and need some serious power to push the cone. Also it would be prudent to get a good management system to run this kind of a setup.