Thanks Dd. It was more work than I thought and the twist was my brothers insistance on the ep600 when he saw them all together. My original plan was to stay with dual 600s and dual 500s. But so far so good as long as the Ultra doesn't bottom. I took the strain off that sub by using its 40hz crossover to limit its mid and upper bass output. The added benefit was flatter response by letting the three Axiom subs work their linear magic and minimizing phase issues from a dissimilar sub. Also the Velo SMS-1 is a great tool for dealing with room nodes for anyone with multiple subs. I recommend you consider it with your dual 500s.
