I've noticed for the past several weeks that my MBP volume controls are wonky. Usually at home i have my volume increased to nearly maximum levels but when im at work, out of consideration for others i often mute my speakers. However, i've noticed that when i mute i have to press the fn+mute button several times before OS X picks up and acts accordingly. I usually get confirmation that i have indeed executed a mute command i.e visual confirmation in the center of the screen BUT the speaker in the menu bar, as well as sound in OS X in general, fail to respond unless i repeat several times. Even sometimes requiring me to play a song in iTunes before OS X recognises that i'm trying to mute. Any ideas what's going on?, I've repaired permissions and all that stuff but no dice.