I recently bought a 15" Macbook Pro Retina and have been noticing the same issue. I can't believe how many problems like this that I and people I know have had. For $2600, there should not be a single cheap issue like this, yet many laptops I have bought from Apple over the years have had them.
I am going to return it and not buy Mac products again, unless I can find a solution that actually works. Seems that the workers at Apple probably don't have a fix, and that replacements might or might not have the same problem. I went into a Cult...er...Apple store and checked other Macbook Pro Retinas -- most of them had the same issue (there's a specific song on YouTube that caused the problem on them).
:-( Sorry to rant, but I paid top dollar and am sick of dealing with chintzy, crappy, cheap problems like this. My girlfriend's $900 Dell laptop does not have this issue.