I will need to know much more about your room to assist you.
Fill out the information in this link. Photos are always a good thing of all surfaces.
What type of 3/4” plywood do you suggest for the ceiling. I am using insulation in my joists to create my diaphragmatic filter and not sure if I should use the finished birch wood or pine or just the cheaper subfloor plywood??? They range in price from $20-$60.
Thanks in advance!