The surround is foam, polysomethingsomething, that won't rot. The Empire won't beat the output numbers of the Dynasty or Conquest down low near tuning, but will exceed both (I think that's what he said) above 50hz. Coupled with some room gain the sub will go deep and loud throughout it's range, but the strength is in how it sounds (horses mouth, I haven't heard it) in comparison to previous Epik subs. That's one reason for discontinuing the 18" models and even the 12" subs...since he's walking all over his price points with the Empire.