Subject says it all - I've got 6 can lights in the theater and the trims still rattle during heavy bass scenes. I was thinking I could run some weatherstripping material inside of the trims to stop the rattle, but wondered if anyone tackled this problem a different way and if it was successful.
I used spray foam that is fire rated. The kind used in walls that is orange colored. Get it at home improvement stores. Works amazingly well. Will melt at parts closest to bulbs so lay down some cloth at first.