OK this is a weird one but its bloody important... i hope someone out there can help me...

My power book is doing something weird. Every now and again the sound switches to only play through the left speaker. I don't touch the system preferences sound pane, it just does it itself. I don't know why this is happening but it is annoying me. How can i fix this? is it a problem with the sound card or just the system preferences.
lol. Happens to me, too, every once in a while. I think I read that somebody else had that problem, too. I don't think anybody's figured it out, yet.
If you use the headphone jack a lot, maybe the connector inside is bent and making periodic contact... thus cutting the internal speaker and sending it to a phantom headphone?
No, no... the system actually changes the sound balance via software. Every once in a while, things will sound heavy on the left... So I go into "System Preferences," click "Sound," click the "Output" tab, and, sure enough, the "Balance" slider is actually a little to the left! I drag it back to the middle, and then, a few months later, all of a sudden, things will sound heavy on the left again. The cycle continues....

The REALLY weird thing is, it's been doing it for years, through various incarnations of OS X....