Receivers do everything from the basics of being the channel hub to being the audio/video
receiver for your television and the FM receiver for a stereo, as well as the "circuit hub" for everything that is involved in your system.
When you do start your search, make sure that you do your homework and get all of the accessories you want as well as a good price on your new theater system.
The most common type of receiver -5.1-channel models- decode the audio information contained in Dolby Digital and DTS soundtracks and route them to front left and right, center, and surround speakers in your system via their five built-in amplifier channels.
If the speakers are what you hear and the TV is what you see in a home theater system, then it will stand to reason that at the core of these systems has to be something, and that something is an audio and video receiver. These receivers are in large part the reason why your sound is either fantastic or super lousy.
The other thing to look for is HDMI inputs and outputs. HDMI connections are the premier format for transferring the highest quality audio as well as video signals, which is extremely important with high definition video and audio being all the rage these days. These multiple HDMI inputs will allow you to connect multiple high definition components and filter them down to one single output to your high definition television.
The more expensive receivers for home theater use will often have more advanced audio encoding and processing as well as preamplifier outputs, which allow you to run a passive signal to dedicated power amplifiers that power your speakers with optimal power that is clean, with minimal to almost discrete distortion levels.