I was wondering what the lowest note is on the tuba? Does anybody know?

Well I mean the lowest note possible.

by CCC you mean the C 5 ledger lines below bass clef, or the one an octave lower?

crap that's low...actually it's subsonic isn't it?

You can hear the overtones of the "double pedal C" (I don't think we call it that over here - possibly C0?)

Wikipedia says: "The lowest note in the widely known repertoire is a 16 Hz double-pedal C in the William Kraft piece Encounters II, which is often played using a timed flutter tongue rather than by buzzing the lips. The fundamental overtone of this pitch is subsonic, and its overtones define the pitch in the listener's ear."