The situation you describe (HT to bedroom) is one of the most difficult sound transmission problems to solve. The simple answer is adding some foam will make little difference. Do a web search on Sound Transmission Class (STC) and read up on the subject. Most effective approaches require decoupling, mass, damping, sealing (if it's not air tight, it won't be sound tight) and careful construction. From a HT to a bedroom you will probably need a STC rating of 60 to 70, which is not easy to do. Ceilings can be difficult because you often don't have the space needed to achieve the STC required. Good luck.