>>Velodyne, HSU, and SVS are three companies who have done this
Sure, but in fairness all of those are bigger than the EP500. The 500 is 19.5 x 19.5 x 15 (5700 in^3) while an SVS PB12-Ultra (for example) is 25 x 25 x 18, almost twice the volume. Even the entry level PB10-ISD is bigger than the EP500. I think Axiom's claims are correct.
A better question is "what else can you get for the same $$ as an EP500 ?". I don't think we know the answer for sure, but at first glance the 500 probably does outperform the low end SVS boxes both in terms of power and performance. The question is how far up the SVS (or Hsu, or Velodyne) line you have to go to match the 500's performance.
Axiom doesn't have the whole sub line covered in the sense that they don't have a "big dumb sub" -- the 350 is the biggest before the DSPs and the big amps come out to play. I ended up with an SVS 20-39PC+ (almost exactly twice as big as an EP500) before the Axiom subs came out... roughly the same price as the EP500 up here. My guess is that the SVS still gives a bit more "bass for the buck" in terms of how loud it can play, but the Axiom DSP gives the 500 some advantages which might make it more satisfying overall, particularly more civilized behaviour at the limits (BTW I have already found the limits of the SVS, although the house starts to make some really scary buzzes and rattles long before the SVS starts to give in
).
