2. Not tried with celestions - I'm guesing that they would sound better... but I'm also guessing that the 'custom' speakers are specialy designed to be better with the bass that that thing pumps out! so, if you get a chance I would try it with both. The 'Closed back' Ashdown cab has 'hot' Celestion speakers - I think this has seven stringers and super-downtune-ers in mind.