(Audio/Video receiver) A combination audio amplifier and audio/video switching device for a home theater. An A/V receiver contains inputs for all the user's audio and video sources such as a cable TV box, Blu-ray or CD player and digital media hub (Apple TV, Roku, etc.). The receiver's video output goes to the TV via HDMI, and its several audio outputs connect to speakers and a subwoofer using stranded wires. See HDMI and speaker wires.Surround Sound ProcessorsA/V receivers support several movie soundtrack formats such as Dolby Digital, Atmos and DTS. They also have built-in audio effects to enhance music and movies.Receivers Have AmplifiersAlthough an A/V receiver has its own amplifiersfor powering the speakers, it generally provides optional outputs to external audio amplifiers if more speaker power is required. In such a case, the receiver functions as a preamplifier (see preamp). See home theater, stereo receiver, digital media hub and digital media server.