This issue of speaker break-in has been discussed over and over, and the general consensus is that it makes no difference.
Here's a quote from the owners manual for the Energy Reference Connoisseur line of speakers:
BREAK-IN PROCEDURES
"It is VITAL that your new Reference Connoisseur speakers be allowed to break-in
properly before you perform any precise set up procedures, system adjustments, and
before you play them at higher volume levels. The best method of performing the
break-in is to play a full range musical passage at a moderate level as long as
possible. Utilizing the repeat function on your CD or DVD player can assist greatly.
Optimum sound will not be achieved until approximately 100 hours of playing time.
After break-in, the volume level can be increased. Do not play the speakers at high
levels until the break-in process has been completed. The transducers need to
“loosen up”, and until this occurs, damage can result to the transducers."
Maybe it makes no difference, but hey, can't hurt!
