Local Source amplifiers are designed to be be used with multi-room audio systems to add a local audio source such as a cable TV box in a bedroom.  The amplifier will automatically switch sources to the TV when audio is detected from the cable box and will return to the multi-room audio system when the TV signal is no longer present.  This enables efficient and seamless sharing of the same great speakers you have installed in the bedroom for either the whole-house system or for using with the room's TV.