them overnight and only came to them after at least 20 more hours of breaking-in. i put the same music on as i did the first time and i was not disappointed - the bass was much more clean and instruments in the bass area were finally as distinct as they should be at this level of headphones. i did not listen to the music during the break-in time, so my brain did not adopt to the sound of these headphones - they actually sounded better.
i do not really care that a distinguished loudspeaker engineer can not find an explanation of how this break-in happens, but that does not change 