When I first got these headphones I was bit worried as I found the high end to be very shrill & the bass very... well very not there, all my music sounded very detailed but it didn't seem to sit quite right, noting really did other then a few songs which showed the headphones true potential but a few songs wasn't going to cut it.
Now I've never been a believer of headphone burn in, I always thought your ears just simply flat out adjusted to them, but the thing was I wasn't really enjoying listening to music on these things so I sort of tried out burning them in based on some other experiences which stated the exact same thing as what I felt when I first listened to these headphones, shrill highs... soundstage being too revealing and rigid.
Anyways I left these to burn in for around 48 hours as I was out for a couple of days and returned and gave them another try and all I can say is, I now believe in burn in, these headphones sounded like a completely different pair I had dismissed just 2 days prior.
The bass was so clear, it was controlled, punchy and responsive... I don't think I've ever heard such controlled and responsive bass on a pair of headphones before... now don't get me wrong don't mistake this for headpounding bass this isn't what these headphones are about but I've never been a much a fan for that anyways, this bass is just soooo satisfying.
The soundstage opened it's self up but music no longer sounded disjointed, you could pin point with precision where everything was in the room, this is ever clearer in movies where these bad boys excel.
These headphones are for lovers of the human voice, female vocals especially sound great on these headphones, vocals in all songs come out loud and clear and sound incredibly organic (unless the producer intended otherwise)
In short I think these headphones are breath taking, suggested burn in time is around 700hours and they sound better each time I listen to them (though I believe it's because I've adjusted as much as the burn in process) I'm reaching around about 70 - 100hours now I'd estimate since buying them and can't wait to hear them at their full potential.