This is bugging me, no matter what set of headphones I use the audio only comes out of the left side. I checked the sound under system preferences, it was balanced to the center, moving to the right did nothing. Next I opened Audio MIDI Setup and everything I changed in there did nothing. Third thing I did was remove the front I/O board from my 2.7 that I know works and put it into the 2.3, and even after doing this the audio still played to the left. I also swapped the black cable that connects the I/O board to the Logic Board. Any ideas? ---------- And I've also noticed the "Bong" when I start up only comes from the left side as well, so certainly not an OS issue. Booted up into Tiger and same issue.