I cranked the volume on mine 'all the way up' and there is NO buzz or vibration. If this occurred on my unit, I would 'take it back' for a replacement. Even so, I don't recommend turning up the internal speakers full tilt. I' don't think they're designed to be played that loud. If you need more volume, get an external PA or listen thru headphones. I just recently purchased a pair of EV SxA100's: http://www.electrovoice.com/New/Main_Sid...eries-Flier.pdf
They sound teriffic with the 2000 keyboard. Now, what were you saying? . . . I can't h-e-a-r you.