Speaker massage ...

Just listen at moderate levels. You can use a streamer service to play a digital radio station continuously at a lower level when you are not home or doing something else. Break-in won't take long - maybe a few days (100 hours). Since I have only bought used speakers for years this aspect has not been a concern!

In the old days we used to put the speakers face to face, reverse the wires on one speaker and let them play. Now we have break in CDs like Isotek, that supposedly speed things up. But playing music normally works too. I would get something with some heavier bass to loosen up the woofers. I like Eriykah Badu for that. Very deep bass and kick drum. And the songs are good as a bonus. 

Thank you @jasonbourne52 and ​​​​@chayro I'm predicate your advices 😊

New woofer suspensions loosen up a bit with playing time, and are more likely to achieve the response they were designed to do once worn in a bit.  Depending on the speakers and the rest of your system, the crossover may experience some audible improvements from burn in too.  You can just give them playing time and enjoy the process, or you can pump them with low frequency signal to move the woofers.  

Or just play some bass heavy music, Bob Marley usually works for me. 😎