I love my PB 13 ultra and the new one is supposedly even better than mine. The PB13 ultra and pretty much most other subs I have heard sound slightly differeent then the Axiom line up. Axiom subs have a smooth rich sound, more textured than the simple thud most subs produce. I feel this sound is more realistic to a live performance however to get the same depth of FR you need to get into the EP800 which has a similar response to the PB13.