I got a 10" sub installed yesterday and I'm getting rattling on the outside of the car on the roof. Anyone else have this problem? The installer said it might be because I have the overhead console box installed. Any ideas? Is there a way to get dynamat up there?

 

It's hard to say without being there to try and locate where the sound is coming from.
If you think it's the headliner, drop it and either put dynamat up there or felt the high edges that may contact the roof and see if it makes a difference.