What experience does anyone have with the Bill Dickens sub and/or Whappo Grande? How loud and how efficient are the two subs? How does each sound with the Whappo Jr. or Bill Dickens Signature 212? How are the various cabinets for handling a low B with power, clarity, and volume---and how are they for a solid, LOUD , deep tone? They sound interesting, but finding one to try is very difficult; and they are a little expensive to buy without an audition.