HDMI combines digital audio and video together. If your HDTV does not have the HDMI interface, your receiver will be ready when you upgrade the HDTV in the future.

Digital Versatile Disc(DVD) and compact disc (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 receiver 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, home theater receivers 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.

A receiver might also support a second set of remote surround sound speakers. These speakers might 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 receivers 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. The receiver’s speaker channels self-adjust so that, regardless of speaker distance, sounds reach the microphone at the same time. This creates a perfect “sweet spot.”