its an old myth about speaker break-in. i used to believe in it, but with loads of research later, i learned there is no such thing.
Its not the speakers that need to be broke-in, its your ears than need time to adjust.
Give yourself a little in the room with your speakers playing and all will sound fine.
The sound of speakers differs from your room and speaker position, most people get a large speaker and place it anywhere within a small room, thats wrong. Some people buy tallstand speakers because the look nice. thats also wrong.
Your speakers should be suitable for your room for maximum sound clarity, e.g: tallstands for large rooms, bookshelfs for small rooms.
Place your speakers in face of your seating spot, there is no point facing speakers towards another wall from where you are seated, Wall bounce of sound occures and distorts sound. (say you had an arm chair in the center of a room, face all speakers towards that chair) crystal sound will emerge.
Hope this helped you out mate