Hi guys, FYI, the documentation shows PKEY_AudioEndpoint_PhysicalSpeakerConfig, but the actual header declares it as PKEY_AudioEndpoint_PhysicalSpeakers. (I am assuming that the meaning is synonymous?!) Also, there is no linkage to the definition of the PROPERTYKEY itself (again EXTERN_C) -- so I've had to define it locally based on the GUID information from the header for now. Thanks, Ally