Two small RELs or One Larger Sub

One larger rel. I have a 212 se.  Best solution 

I use 2 RELs from an earlier era and they're amazing...a Q150e (10") and a Q108II (8")...bought them used for 200 bucks each few years ago. I also have a "pro-studio" monster sub (in my studio) that's flat to 19hz and I've dragged its 92lb high powered mass into the hifi room to see what's what...it worked fine but...meh...the 2 RELs are enough lowness...I don't like DSP as it seems to be somebody else's "electronic opinion in a box" (I'm a pro sound tech so I could simply be a Luddite) but they may be a useful shortcut for some. I think you can adjust REL's enough to make them easy to use and enjoy...2 are good...

Thanks for the responses!  

It seems two two smaller or mid sized might be a good bet.  I have a small Sumiko sub in another system—I think it’s an REL clone.  It’s so musical.  I’m definitely going to stay in the REL family because I like their philosophy of what a sub is supposed to do. 

Maybe ill I’ll start with one and see how it goes.

I had 2 s2 before. I like the 212se better 

I have done and read some on the subject manner.
The following link was the information I found to most helpful in obtaining a well balance, flat frequency that closely matched the SPL of the main speakers and minimized frequency cancellations and bloom.

The sound is omni directional and it sounds as though it is being broadcasted from the main speakers and correctly positioned in the overall sound stage 

This may be helpful to you

http://www.decware.com/paper01.htm

Brad