The Audio Visual Receiver (better known as the A/V Receiver) is the heart of the system, is an important part of the home theatre system and without an A/V receiver you can not have a home theatre set up. It is an amplifier, preamplifier, video processor and an audio decoder built into one. There has been a lot of development in the audio and visual technology in the last couple of years. Because the A/V receiver does everything for you, you connect everything to it. Once its set up correctly it knows what it needs to do. Using the remote control, It switches between things that are connected to it like your Blu-ray player, CD player or what ever you select and output the audio and or video to where it needs to go. Almost all A/V receivers have a radio built it. Many have the ability to power an extra pair of speakers in a different room. This is what is referred to a second zone.
Pictured below is a Marantz SR6012 and the rear of the Yamaha RX-A870. Two popular A/V receivers manufacturers.
