V4 latest version tweeter is what I have. The speakers are only about a year or two old. The right speaker is about 5 feet from the wall behind and 5 feet from the side wall; the left speaker is about the same, however is has a balcony at 8 feet over top. The right speaker has an 18 foot vaulted ceiling above. My sub is about 30 feet away at the opposite side of the room from the T's in an alcove with again an overhung room overhead at about 8 feet. The main living area is all open above up to 18 feet. It's a difficult room to work with, however after a lot of trial and error, I am getting it dialed in. Believe it or not, one mid sized sub (the Def Tech 500 watt cube) working in the alcove with the T's across the room blows away anything I heard out of the SVS's I used. Disclaimer: I did not try the SVS's in the Alcove as I didn't have the opportunity to do so. I moved the Def Tech into the corner out of an experiment to see what would happen if I were to build in a sub into the bar I plan on building this winter..... low and behold, it just works!
I suspect that a second sub or perhaps a third at some point might round out this room even better. But I wish to just play with the EP500 first in the bar area. I have a perfect location for the second sub adjacent to the fireplace about mid point/left between the rear bar sub and the main Model T's. If I do this location, I might consider the EP800, however I think the smaller EP500 might blend in better for balancing the sound. I suspect that multiple smaller subs might work more harmoniously: I'll have to defer to Ian on this one before I get too far into this project.