Speaker massage ...

Break in time probably depends on the surround material. Mine took 300-400 hours and the difference in the bass performance was huge. Happy listening 

I can also advise just to listen to them and watch them change, I found that quite enjoyable. You’ll enjoy them out of the box, but you’ll notice over time some changes for the better and I think that’s part of the journey. Trying to break them in quickly means you’ll lose the education you’ll get on the development of your speaker, which could be invaluable when identifying what you like/dislike for any future purchases. 

when doing the OOP trick during speaker burn-in, best results [the most cancellation/reduction in volume] are gotten by summing your test signal to mono first, if it is not already mono.

I only had one pair of speakers that changed during break-in. It only took 24 hours. Just playing music the drivers will go through a million cycles in a very short time. 

Invite your neighbors over for a eurobeats dance party and turn it up! The bass speakers benefit the most. 

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

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.  

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

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. 

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!