Klipsch THX-5002-S In-Ceiling Speaker, EachTHX ULTRA CERTIFIED Works well with multi channel movie and music presentations playing up to reference levels in rooms of 3,000 cubic feet or larger. CINEMA QUALITY SOUND Employs dual 5. 25 inch Cerametallic woofers that operate in an enclosed tuned port chamber. These exclusive woofer cones offer superb damping characteristics that will not flex or resonate at frequencies within the drivers operating ranges, resulting in consistent bass response