I think because this is more like static versus say heavy drumming the sound helps to excersize and limber up the driver versus causing it to loose it's elasticity.
Hi Shigzeo, when I did my measurements I got significant fluctuations. What I did was continue to work to get the mic and IEm in the right spot so they had a constant reading and only used the highest reading that I could get for both IEM's.
Anaxilus, I'm afraid this is no imagining, the reading no matter how crude are real. To be honest I suspect with better equipment I would be getting even more variation than what I have been able to record now. I even had my wife listen to both IEM's without telling her anything about which IEM should sound and she noticed a difference between the two IEM's and described the sound differences I am noticing and believe you me she doesn't really care about all this stuff at all. What I hope is that some of you that download the file (I put up a flac version last night BTW plus a FLAC file that shifts it's focus from bass lower midrange to mids and treble as well) will see some overall improvement even in burned in Copper's as this would show this file can be used on any Coppers, not just new ones. But I do also suspect that a new pair might be more influenced by this treatment as it would shape their sound while the driver is in it's infancy so to speak.