Most people around here will tell you that speaker break-in is accomplished in a matter of minutes or seconds.
Others, Mainly at other forums may tell you times up to hundreds of hours.
The simple explanation is just play music like you would regularly and dont worry about it. Speakers are primarily mechanical devices and usually do seem to benifit from being played a few hours before sounding their best. There are no special recordings you need to accomplish this however. Just sit back, relax and enjoy.