Subwoofers

@greywolf In a room that size you are going to need two 15" or four 12" drivers at work. I design and build my own subwoofers and I only recommend the brands KEF, Martin Logan and Magico. I think what would best suite you would be two Martin Logan Balanced Force 212s. Balanced force subwoofers have matching drivers at opposite ends of the enclosure working in phase so both cones extend and contract at the same time cancelling out all Newtonian forces.The subwoofers produce less distortion. At this time REL, SVS and JL Audio make nothing like them. If you are going to do subwoofers a two way crossover is IMHO mandatory to get the best performance out of the system

Well Rhythmik has a foam surround, the Martin Logan costs to much. Still undecided.

It looks like you may be selling yourself a little short. With that nice of a set of speakers, I would think a set of REL carbon specials could do the trick properly. Plus, that way as time goes by you can save your pennies and start stacking them for a line array. Or you could just use a pair of 212/sx and be done with it. Good luck 👍 most jealous of your quest. 

Carbons are more than I want to spend. 

what do you all think of this sub 

https://www.crutchfield.com/p_265B1122WA/Revel-Performa3-B112v2-High-Gloss-Walnut.html?tp=187

@greywolf I haven't heard the Revel, but I notice that it only has line level inputs.  Maybe that works for you, but I like connecting the REL with speaker level for two channel.  It also has separate line level inputs for a LFE channel if your system doubles as a home theatre line mine does.  You can use both inputs simultaneously and it has separate gain controls for each.  

I also noticed that the crossover frequency is shown as 50 to 150.  To get my subs to blend, I'm considerably lower than 50. Not sure if that's a problem.