A receiver is the main hub of a home theater system. All components in the system are cabled to it, and it serves as a controller. The most important factor in connecting theater components is to make sure that it have the correct input and output ports, including the newest interfaces available. High-definition televisions (HDTVs) use an interface called High-Definition Multimedia Interface (HDMI), which combines digital audio and video together. Even if your TV does not have the HDMI interface, it's best to get a receiver that does so that you'll be ready when you upgrade the TV in the future.
DVD and CD players, computer graphics cards, liquid crystal display (LCD) monitors, and portable electronic devices like digicams and cell phones are all migrating to a new audiovisual standard called Unified Digital Interface (UDI). UDI is compatible with the HDMI used on HDTVs. With UDI input and output ports on your receiver, you will be able to take advantage of the latest interfaces for DVD/CD players and portable devices. A device with a UDI-out port can also connect to a UDI-enabled computer graphics card to stream television to the computer.
The receiver should also able to accommodate optical or digital audio interfaces, as well as older style analog left/right cabling. In other words, it should be backwards compatible with older technology so that you can upgrade existing components at will.
While stereo receivers only support two speakers, ones designed for home theaters support surround sound, or multiple speaker systems. The most basic configuration is 5-1 surround sound, which includes five speakers and a subwoofer to deliver bass. Newer configurations include 6-1 and 7-1 surround sound, or seven and eight speaker systems respectively, with a subwoofer included in each case.
The device might also support a second set of remote surround sound speakers. These speakers could be located in a bedroom or on a sundeck. Remote surround sound speakers can be activated separately from the main speaker system.
To easily set up a surround system, look for a receiver that offers automatic calibration. These devices come with a small microphone and front microphone port. The microphone is placed in the area where you would like the sound to be optimum, such as on a facing couch at ear-level. By engaging the calibration program, the receiver emits a series of signals and sound effects, electronically measuring when each speaker’s output reaches the microphone. Its speaker channels self-adjust so that, regardless of speaker distance, sounds reach the microphone at the same time. This creates a perfect "sweet spot."
Typical features include equalization settings, controls for switching between connected components, and on-screen setup menus for easy navigation. If you plan to use portable electronic devices, look for front auxiliary ports so that you will not have to reach behind it to use a device. The price you pay for a receiver will depend upon on the amp power and specific feature set. Since it is the hub of the home theater system, it is generally money well spent to get a good one that will be reasonably future proof and provide you with a breathtaking home theater experience.