subs for Sonus Faber Cremona M floor standing

I use 2 REL Stadium subs with my Gamut L5s, which are similar in size and frequency response to the SFs. I was looking for a pair of Cremonas myself before I got a great deal on the Gamuts. The JL is suppose to be very good also but I haven't heard them.

I from time to time use a REL Stentor with my Sonus Faber Cremona Auditor Ms.

I used to use 2 REL Stentors and withim the last 48 hrs have been fine tuning a JL f113 which already is outperforming the Stentors! Faster, more muscular and the JL has a sense of effortlessness that is just wonderful.
(dealer disclaimer)

Dear Erictye: Your Cremona ones crossover 400hz from woofer to midrange and this means that using two active subwoofers in true stereo fashion ( the subs has to have high-pass filter. Rels does not have so you need other option. ) will gives you a great improvement in the quality performance level of your system, not only " more bass " I'm talking of overall quality level because two subs in stereo fashion helps to lower the IMD of your main speakers. You will be amazed when you hear this kind of set-up. Yes, the Cremona's will work as your main-satellite speakers in your " new " bi-amp speaker system.

Please if you have time read these links:

http://forum.audiogon.com/cgi-bin/fr.pl?eanlg&1117893153&openflup&27&4#27

http://forum.audiogon.com/cgi-bin/fr.pl?eanlg&1117893153&openflup&31&4#31

Now, I use Velodyne subs for very good reasons and between them is that IMHO no one knows more about subs that Velodyne, they have 28+ years designing/build subs and only subs. His patented servo controled/accelerometer sense the woofer response/behavior around 16,000 times every single second and correct when it need it and this helps, between other things , to achieve the lowest THD on any sub out there: lower than 0.5% at 120dbs!!!

You can read more on these subs here:
http://www.audioholics.com/reviews/speakers/subwoofers/velodyne-dd-18/velodyne-dd-18-subwoofer-first-impressions

No, I don't have any single relationship in anyway with Velodyne other that I'm an owner.

Regards and enjoy the music,
R.