MPAC and UMR are proposing development of an Acoustic Control System for high temperature gas flow in ducts. This control system is based on a passive inorganic acoustical coating. MPAC has developed and applied for a patent on a architectural acoustical control coating with unusually high wear resistance, a noise reduction coefficient of 0.5, and excellent low frequency damping. UMR has long experience in modeling acoustic treatment in ducts with high speed flow and has world class facilities for experimental characterization of acoustic materials and systems. The proposal team is committed to a phase one proof of concept deliverable consisting of passive coatings for application. This acoustic control coating, if successful, would provide a very low cost high reliability acoustical damping for hot gas structures.