I will take my macbook air to the genius bar tomorrow and let you guys know what i can figure out about the problem. I had wifi issues before so i'm really beginning to consider returning this laptop... It has been a feeling of golden handcuffs for the most part so far...
Anyway: how about you guys give this audio/video file a try? Everytime i watch the news (in dutch) the volume levels are fluctuating... source: Laatste NOS Journaal
I've tried it with my girlfriends laptop, just a standard windows one, and it doesn't fluctuate at all... Same on my old desktop pc.
Will keep you guys up to date... Maybe people can post if they experience any volume fluctuations of the news item i provided.