I am not a big believer in burn in but will keep an open mind with possible effect on the Amiron. Remember that magical 150 hours with the NH? I had to laugh at all those comments about how they dramatically changed in sound. Always thought it was nonsense.
I'm not huge on burn-in either but it does happen some in my experience, but it won't completely change a headphones, it's pretty much always very subtle imho, the NH barely changed if at any. It didn't become clearer or anything, that was just adjusting to the sound. With the Beyers it's not really a frequency change, I just find at some point the sound starts becoming really sweet and gains a little bit more body. My main problem with the Amiron until today was where was the euphony compared to the DT 1770 and DT 1990, well it showed itself, lol. These are the Tesla 2.0 drivers I know and love. My impressions haven't changed in that I still find the DT 1990 more upper mid-forward, slightly brighter, and more linear bass.