It's a shame that the information Musicnoise typed out gets run at Audiogon. Invariably there will be newbees that believe what he said and possibly sell a good pair of speakers before ever knowing what they really sound like.
Lightminer is correct:
Both scientifically and by common sense and old fashioned listening to music.
Lightminer is correct:
with Magnepans at least you can take a Radio Shack SPL meter and measure the falloff at a certain level of input in bass, and 3 months later the response curve is different. I don't know as much about cone speakers and personal experience with breakin but I can say scientifically that the Maggie 3.6s sound *very* different on 1st day and 3 months later. And, as I said, I can verify this with instruments and graphs.
Both scientifically and by common sense and old fashioned listening to music.