Jay is trying to help a friend reduce echo in a large studio stage. How can they refine that so they can do some filming there? Scott says it's likely that the stage recording will be replaced with ADR. But he'll need to do some acoustic treatment to the area anyway and that requires a pro. He advises talking to the pros at PMI, Ltd. in Los Angeles. They should be able to point him in the right direction if they can't help him themselves. It all comes down to his budget.
A lot of this depends on the construction of the building. For an older building with thin walls, it'll be very difficult. The best sound suppression is an "air gap". Many sound studios will have double panes of glass with a vacuum in between, they'll have an air lock with two doors, raised floors, etc. All sound is vibration, and vibration goes better through solid materials than it does through air or a vacuum.