Okay so I just had my Ashdown ABM 500 replaced under warranty ( lettering was rubbing off the face ) and I took it to the spot to test it out with my Schroeder 410. Now previously I could get to a very specific volume level before the amp would start to clip on an open B, specifically at about 2-3 o' clock on the volume knob. The new one seemed to be breaking up a lot sooner like at 10 or 11 o'clock. I suddenly realized that the subharmonizer was engaged full blast. Turned it off, everything went back to normal. After about a 5 hour rehearsal, I started to notice a REALLY bad noise coming from the cabinet. Kind of like the sound get when you hold a piece of paper out the window of your car on the freeway. Unless I played VERY gently I would get this sound anywhere on the B, E or A strings. This did not sound like clipping and it sounded as if it were coming from the "folded" part of the cabinet, as if it was a specific speaker..... ideas? If it isnt a bad speaker that means I've somehow damaged a brand new amp....., if it is a bad speaker, how do I tell which one?