Its true that the t/s parameters of a woofer change as the voice coils heat up but as soon as the music is turned off and the woofer is allowed ample cooling the t/s parameters revert back. When I am talking about t/s parameters changing we are talking about temporary, relatively small and inaudible changes. As for the tweeters, no they do not break in.

On the other hand psychoacoustics is a real phenomena and what many perceive as speakers breaking or burning in.

I’m armed and I’m drinking. You don’t want to listen to advice from me, amigo.

-Max Payne