You don't have to break in a sub... but if you want to, just to be on the safe side... Just listen to it at normal listening levels. After about 2/3 days, then you can try to show off.:-) Its safe to turn it up.
i advise about 48 straight hours of low-medium volume listening. as previously stated, that's about 2wks. the suspension, vc, the entire sub is going to be stiff. needs to get loose or you will break, separate things.
Yes, 48 hours of listening is what it takes. Not 2 days, but 48 hours of listening(usually 2 or so weeks)...their will be a difference in sound quality as well when it loosens up...you won't notice it but people getting in and out of your car every few days will.