I must ask, really! What do you play when you run in the drivers?
I'm usually not in too much of a hurry to break things in to be honest, so I try not to resort to specific "break in" music so much as just stuff with bass that I really like to listen to.
But if I am in a hurry, I use the Hafler DH100 at nearly bottoming out point for the drivers, and I run something with heavy bass like Notorious B.I.G. (but not stuff that's methamphetamine inspired like Prodigy).
But - on current rotation is DJ Krush, The American Analog Set, Kurt Vile and Grateful Dead.
DJ Krush is great when you stream from MOG radio "artist only." I've seen him a few times, Seattle and Tokyo and Seattle again on his 50th birthday. He was truly groundbreaking in this genre... and still is. DJ music ain't just for the young!
For Grateful Dead I am really into the Dicks Picks series, just working my way through. The Vol.3 is a really good set I just came across. I'm not a well informed dead head, but definitely go through stages here and there where its all I can listen to. Seems to be spurred on by the coming of summertime!
Kurt Vile is another "checker" type of music. The potential harshness of his vocals will really destroy most single drivers' tonal characters. Got to see him just last week at Neumos. He is so good. One of the greats of modern times IMO.
Have been using line arrays in the shop recently to get enough volume to overcome all the recently added tool noises. I don't know where my mind would be without loud music (and loud tools) sometimes!
Cheers man,
Clark