Best subwoofer below 40Hz for Magnepan .7?

Now that I've researched the Antimode 8033 I might have to get one someday as it's small enough to fit in my rack…note that my aforementioned ego won't allow me to retract my seemingly endless arguments against these things, so I won't say anything if it works. That's just how it is.

wolf, how’s Loki as a bass and treble control? I see it has controls at 20Hz and 8KHz with +/- 12 dB range. Does it add a clean subtle bass as well as make the cymbals sound more crisp without sounding bright and tinny?

From what I understand the Loki is a Baxandall type tone control, covering a pretty wide range, whereas a system like the Antimode (or an REW corrrection curve) is a very precisely targeted precision weapon. And it is very small indeed. Mine just sits behind my power amplifier, out of sight and out of mind.

What about the multi sub system from Audiokinesis called Swarm? Might be the answer...

Can anyone tell me how a multi sub config is connected to the amp?
I can understand 2 subs, but 3 or more? 
B