Speakers suddenly buzzing

[leviathanguthri]

Hi guys,

Out of nowhere my Macbook speakers are suddenly buzzing (as in distorted) when volume is turned up high, above say 80%. I have googled it and tried a few things:

• The sound works fine through both headphones and if I put it through my TV, so as far as I know that means the sound card is ok. (correct me if that's not right!)
• I have tried PRAM and SRC reset.
• I have opened and closed Garageband.
• I have tried putting the headphone jack in and out.
• I have made sure on Audio/Midi that the inputs and outputs are ok.
• I have deleted my Quicktime preferences.
• I have looked at the balance - both speakers are affected.
• I do not have the equaliser activated on iTunes.

I have a fairly clean Mac, there is nothing weird on there in terms of sound-related programs. Lately I have been playing things on full volume at times so I know some kind of rip in the speaker is possible, but I don't really want to pull things about until I am sure that is the issue.

Any ideas?