I recently upgraded my 5.1 system, and all the new speakers basically said the same thing: "The speakers will sound great out of the box, but after XX hours they'll sound even better." Generally speaking, 40 - 60 hours was quoted.
I did leave the system running for a week, and after that time the speakers did clean up, with the sub sounding the most improved. The receiver seemed to agree, as it's suggested crossover settings were lower and more in-line with the speakers' ratings following break-in.
My question is: What actually happens to the speaker during the break-in process which allows it to play at the designed level?