Speaker massage ...

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. 😎

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

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. 

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.