On October 10, 2017 at 11:08, Gman said...
We in the midst of a theater prewire and some concerns have come up with the owner for soundproofing. There are 2 8 inch HVAC runs going through the room. The ceiling will have quiet rock and roxul above it. Would applying Dynamat to the pipes work to keep the sound from traveling through those pipes? The website looks like it is used only to stop metal rattling only?
You could change the ducting to something made to attenuate noise, wrap it with thick fiberglass after spraying sound deadening insulation on or build an enclosure around the ducts, too. Either will cost headroom, but are effective.