I am in the process of adding a basement with a dedicated theater room. right now during the construction phase my metal register boxes for the upstairs HVAC are exposed. Sound is passed through these metal registers very easily. I am planning on using whisper clips, 2 layers of 5/8" drywall and green glue on the ceiling. Will this take care of all the sound or should I wrap the metal register boxes with MLV or any other product before I drywall the ceiling? I am ripping everything out and having a new HVAC system and new register boxes installed in the next couple of weeks so now is the time to do it if there is a benefit. Any help is appreciated!!!!
I've thrown some dynamat supreme on the boots in the past and I liked the result. I've also lined some with Linacoustic. if they are connected with round pipe substiting flex duct for the last few feet can often provide a benefit, And of course surrounding the ducts with insulation.