I'm planning out my theater layout, and looking at the various ways to float the floor for the "room within a room." Has anyone thought about using actual hockey pucks under the base plates and plywood? (Maybe you could use construction adhesive to glue them to the concrete floor?) You can buy pucks for under a dollar each, and they should be able to bear a significant amount of weight. Another idea is to put sand in between the pucks, so as to deaden the air gap between the plywood and concrete. I'd appreciate your feedback.