About Home Theater Receiver Features

5.1-channel input
This 6-jack input lets you hook up an external multichannel (Dolby Digital, DTS) decoder, or a DVD player with built-in decoding. Known as "5.1-ready," these receivers are also compatible with new 5.1-channel music formats like DVD-Audio.

When shopping for a receiver, notice the range of frequencies, or bandwidth, listed next to the amplifier power rating. For audio components, "full bandwidth" is generally considered to be the entire frequency range of human hearing — 20-20,000 Hz. Full-bandwidth power ratings are a more conservative measure of power than ratings derived using a narrower range of frequencies.

Digital inputs
Dolby Digital and DTS receivers and decoders have optical and/or coaxial digital inputs for accepting the multichannel digital output from a DVD player, or the stereo digital output from compatible audio components (CD and MD players, etc.).

Optical digital connections require a special type of fiber optic cable, known as Toslink. Though coaxial digital connections use standard RCA-style jacks, a coaxial digital audio cable designed specifically for the wider frequency bandwidth of digital signals is recommended.

Digital output
Lets a receiver send stereo (PCM) digital audio directly to digital recorders (such as MiniDisc, CD-R, or DAT).

Digital Signal Processing (DSP)
Some receivers use Digital Signal Processing for creating soundfields (simulated acoustic environments) and for precise steering of multichannel Dolby Pro Logic information. When an audio signal is processed and routed in the digital domain, it is less susceptible to signal loss and added distortion.

Discrete output transistors
Found in higher quality receivers and amplifiers. An amplifier output section comprised of discrete transistors offers some big advantages over the more common, low-cost IC chip amplifier: higher current capacity, ability to handle more heat, quicker response to sonic transients, lower distortion, more dynamic and lifelike sound.

Dolby® Digital
The designated digital audio format for DVD, HDTV, and select laserdiscs and satellite TV broadcasts, Dolby Digital can include from one to six channels of sound. "5.1-channel" Dolby Digital has 6 discrete digital audio channels: 5 full-bandwidth channels (for front left/right, center, and surround left/right) and 1 "low frequency effects" subwoofer channel.

Some receivers have Dolby Digital decoding built-in; others, known as "5.1-ready," have a 6-jack input for hooking up an external Dolby Digital decoder (or a DVD player with built-in decoding).

Dolby Surround Pro Logic
This type of decoder, found on most home theater receivers and processors, delivers multichannel playback of Dolby Surround-encoded stereo sources (like videotapes, stereo TV broadcasts, etc.).

A predecessor of the discrete 5.1-channel Dolby Digital system, Pro Logic includes a center channel for on-screen sound; front left and right channels for sound that moves with the action; and a time-delayed mono surround channel sent to the left and right surround speakers to provide ambience and sound effects.

An established digital multichannel audio format in movie theaters, but a relative newcomer in home theater. Like Dolby Digital, DTS is a "5.1-channel" system. Few DTS-encoded DVDs or CDs are currently available, however the number of compatible DVD players and receivers is growing.

FM sensitivity
Indicates a receiver's ability to pick up FM signals (a lower number is better).

High-current power
The flow of current through your speakers' voice coils creates the electromagnetic force that moves the cones and domes, creating sound. The dynamic qualities of music and movie soundtracks create short-term high-current demands. If current flow is limited, the sound will be, too. A high-current amplifier (or a receiver that uses one) may sound punchier and more powerful than other models with the same wattage rating.

On-screen display
Some A/V receivers let you view component/system status on your TV screen. Some use a GUI (Graphical User Interface) for easy remote point-and-click control via on-screen menus and icons. An alternative approach is to display menus and icons on a remote's built-in LCD screen.

Phono Input
Lets you connect a turntable directly to your receiver. Phono signals are a much lower voltage than other audio signals — a phono input lets you make the connection without the need for a separate phono preamp.

Power amplifier
A power amplifier takes the low-voltage signal supplied by a preamplifier, and amplifies it to a sufficient level to drive speakers. Receivers contain both preamplfier and power amplifier sections within them.

Also called a control amplifier or control center. A preamplifier (or preamplifier section of a receiver) handles the switching and selecting of signals, as well as amplifying them to the voltage level required for the input of a power amplifier.

Preamp outputs
On receivers and preamplifiers, these connectors provide unamplified, low-voltage, line-level signals for components like a powered subwoofer or a separate power amplifier.

Remote control
The capabilities of receiver remotes can vary a lot from brand to brand, and even from model to model. We group remotes into three different categories:

* Audio/video remotes can operate several audio/video components from the same manufacturer.
* Multibrand remotes have pre-programmed codes for popular brands of gear.
* Programmable remotes (also called "learning" remotes) can be programmed by the user to operate audio/video equipment from other manufacturers.
An audio component that combines a preamplifier, amplifier, and an AM/FM tuner in a single chassis.

RMS power vs. peak power
The amount of continuous power, measured in watts, that an amplifier produces is called RMS power. The higher the RMS figure, the louder and cleaner your music sounds. When choosing an amplifier or receiver, the RMS rating is the power rating you should pay most attention to.

Stereo manufacturers often display peak power ratings on the face of their products. The peak power rating tells you the maximum wattage an amplifier can deliver as a brief burst during a musical peak, like a dramatic drum accent. The RMS figure is more significant.

S-video inputs
Using a 4-pin connector, an S-video jack transmits the chrominance (color) and luminance (brightness) portions of a video signal separately, for improved color accuracy and reduced distortion. Receivers with S-video inputs offer convenient remote switching for your high-resolution video sources.

Tape monitor loop
An especially versatile type of tape input/output loop found on some receivers and preamplifiers. It allows you to record and play back like a standard tape loop, but can also be used for connecting an equalizer, surround sound decoder, or other external signal processing device.

THD (Total harmonic distortion)
A measurement of the accuracy of an amplifier (or the amplifier section of a receiver). THD refers to the amount of internally generated noise. The lower the number, the better.

Video dubbing
A "dub" is a copy of an original. A receiver that offers video dubbing lets you make a video-to-video copy through the receiver.

Using an A/V receiver as the intermediary unit in the dubbing process has several advantages: You can use the receiver's internal switching, eliminating the need to hook and unhook cables between your video components, and you can easily monitor the dubbing process using the receiver's connections to your TV and speakers.