Steve here is a buyer review of the Crystal for ya, hope it helps
15" CMPX2 UNLEASHED!! by djtrini March 20, 2002
I have this sub running in a 4.5 cubic foot enclosure slot ported tuned to 35hz being powered by a Autotek XS1500.1 (1500x1 RMS @1ohm MONO) and this subs absolutely SLAMS!
I struggle to breath on a regular basis, I LOVE THIS SUB!
What i LOVE most about this sub is it's ability to play well with all kinds of music.....BASS MEKANIK!!
I have gone through many subs (Pioneer, RF HX2's, Pheonix Gold, RF punch DVC's, CV Stroker, JL Audio 12W3's etc)
CMPx2 is by far THE BEST! It was waaay Louder and Cleaner than the 3 12w3's I used to have, and Just as Loud or almost as LOUD as the Stroker with UNGODLY amounts of SQ!
Everything in my van Flex's! The rear windows open for themselves.....It Actually Cracked the back hatch Door on my Van....the Sound Pressure is that LOUD! All my doors flex atleast 2 inches, my roof and windows all flex! And to keep my rear view mirror from falling off all the time I had to SUPER glue it down!
CMPx2 has the BEST SQ I have ever heard, and the SPL is just well.....LOUD!