I have found that I had my room treated for Merlins, so I had damped the room a bit (to offset their "personailty")... I found as I removed some of the Echotunes/roomtunes/cornertunes devices, that live sound returned, that air returned, while still keeping that quad/stat cohesiveness to the huge stage... Also removing some of the roomtunes helped the 2c3d thing to "pop" into place. The only room treatments left, are those in the lower half of the rear wall corners, BELOW the Ohm canister - I found any room treatments above the canister to damp things down too much here.
Also, like others in this thread have mentioned, I have the speakers level, and level with each other. Makes a big difference here with the 2C3D thing also. Getting the canisters to fire at the same angle and height. All walls just melt, with my Ohm's 6-7 feet apart, firing straight out into room, 3' from side walls, pulled well out from rear walls (using the Cardas method for speaker placement), 11' to listening position (good sized room).
Like Ultimatezap found, just a huge stage. and I have found I cannot make them sound un-musical - and even when crazy loud on big symphonies or metal, you can still hear the person next to you.