I just talked to Axiom, it appears the output of the EP600 (and I assume 500/800) are great enough that other subs in the mix will require lots of gain to be equal. This can be a bit tricky. As most of you EP owners have realized, you have to keep the gain almost all the way down as a higher setting will require the receiver to be set down as low as -10to-12dB to compensate.
Then, to get the other subs at the same SPL, you have to almost max them out. You can't raise the receiver level to help, becauese this would require the 600 to be lower, and your out of room.
Maybe some day receiver manufacturers will figure out that independent multiple sub preouts are required.
