how do you know when your new monitors are "broken in"?

Its fairly quick, with louder volumes. A low frequency sine wave at about as loud as you can handle for about 5 minutes gets most of the break-in taken care of.
 
I just put my iPod on shuffle through them last night while the GF and I played Arkham City. So close to beating that game!

It wasn't loud loud but we could hear it in the other room with the doors open. Should be pretty good to go then. Can't wait to mix on these things :headbang:
 
I put the monitors facing each other, one with the phase flipped, and just play all my itunes songs. (let play for some days at different volumes).