rimmi, some say there is a burn in, some say no, for all speakers that is. Paradigm says they do it at the factory... I say just play it, drive it hard after a couple of hours, you want to know if it can perform now and not find out later that it's faulty for some reason. There is some comments about this very thing many pages back, some links to articles from 'experts' on both sides of the burn in topic. If you google speaker burn in you'll find hours of reading, 50%/50% yes/no!
ps; all my speakers look great cover off, they are all different, fronts, rears, centre and F12, but I know that speakers are dust magnets and a pain to clean. Mine stay on unless I'm a bit buzzed and want to see all 9 of my woofers dancing to some LOUD music.