subs for Sonus Faber Cremona M floor standing


My system includes Mac C2300, MC2102. I have it narrowed to the JL F113, Rel or SVS. I am looking to integrate it to the system... Not for the boom boom boom. This system is 2 channel for audio not home theatre. As the SF are amazing I just want to bring a little more low end back into the system. I was running Klipschorns biamped before this so I am missing the walls shaking ;)
erictye
Raul, IMHO, a sub that matches well with SF Cremona M's is going to be a sub that is suitable for Erictye's room. Whatever sub that he ends up with will have to be fairly quick and easy to 'blend' with the Cremona's. In my system, the answer was the Rel T5, because a) I have a very small room and anything larger will overload it and 2) my mains (SF GH's) are lighting fast and I know of no large driver ( we're talking 10" and above) subs that are quick enough to match these mains, so the REl was the answer . If one is looking for more extension and they have a larger room than I along with slower mains, then i suspect that most if not all of the larger Velodyn'e would be fine, just IMO.
One other thing that I forgot to mention in the Rel's favor....the hook-up scheme is IMO better than competing designs. The Neutrik connector allows a hi-level connection directly at the amp terminals, which allows the signal to be more precise to what the speakers are seeing at the amp terminals. I do think that this leads to a more "accurate" reproduction than taking the signal from the preamp, as in all other models that i am aware of......again, IMHO.
He's my dilemma: I already have one REL 505, and I can find another on 'Gon for about $1000. If I switch to the Velodyne DD12 (same piston size as the 505)I will want/need 2 and the cost will run to $3000+ if I buy them used.

My question is, will 2 DD15's truly outperform 2 505's? I mean hands down, no questions asked undeniably better?

Thanks,
Mike
Okay - just back from the Velodyne website where I found the Optimum 12. The Optimum 12 is a bit more than half the price of the DD12 plus - so what would I give up if I go with the Optimum 12 over the DD12? And is there any experience with the Opti 12?

Would the Opti 12 be considered better than the REL505?
Dear Daveyf: Options always are open, IMHO all depend on each one targets/priorities on quality level performance.

+++++ " my mains (SF GH's) are lighting fast and I know of no large driver ( we're talking 10" and above) subs that are quick enough to match these mains, " +++++

this link touch that " myth ":

http://www.soundstage.com/maxdb/maxdb061999.htm

Regards and enjoy the music,
R.