I think I'd tend to argue the side that it is 'mental' break-in rather than 'physical' break-in. I bought a pair of demo M60ti's about 3 weeks ago, and when I hooked them up to my Yamaha receiver, I felt they were pretty bright. But I'm really starting to enjoy them now and believe the highs are less pronounced. Since these were demo (though used sparingly) the speakers would have already been broken in. The only thing I can think of, is that I've gotten accustomed to the sound and speaker break-in is all "in your mind"! I do love them by the way!
