ibook speakers

last when, when i was on vacation, i opened my ibook from sleep and the speakers immedietly made this really bad hissing sound, kind of like a tv with no signal. it stopped after a few seconds, but then the speakers wouldnt work, so i restarted, and they did. now, i realize that only my left speaker works. could this be a result of the hissing sound, or is there some setting for left right that i accidently clicked left. any suggestions?

Check your balance settings in the control panel just to be sure.