Today’s receivers connect to audio, television and DVD equipment.

The receiver is the heart of a contemporary home-theater system. It connects video sources such as a TV, DVD player, VCR, and cable or satellite box, as well as audio components such as speakers, a CD player, cassette deck, and turntable.

Receivers started out as audio equipment, providing AM and FM radio tuners, stereo sound, and switching capabilities. But as they have taken on a pivotal role in home entertainment, they’ve lost some audio-related features that were common in the past, such as tape monitors and phono inputs. Manufacturers say they must eliminate those less-used features to make room for others. Even so, a stand-alone receiver generally provides more functionality than one bundled with speakers as a home-theater-in-a-box system.

Sony is by far the biggest-selling brand of receivers. Other top-sellers include Denon, Harman Kardon, JVC, Onkyo, Pioneer, and Yamaha. Most receivers sold today are capable of handling the multichannel audio in DVDs and some TV programming, but stereo receivers are still available. Here are the different types you’ll find:

Stereo. Basic receivers accept analog-stereo signals and provide two channels of amplification for a pair of speakers. For a simple music setup, you can add a DVD or CD player to play CDs. A basic home-theater setup consists of a TV and DVD player, a receiver, and a pair of speakers. This setup gives you the most noticeable improvement in TV audio. Stereo receivers typically output 50 to 100 watts per channel. Price: $125 to $250. “Audiophile” models can cost thousands of dollars.

Multichannel. Most of the action today is in the multichannel category. This is the type of receiver you’d want for a full-featured home-entertainment system. Most new receivers have 6.1 or 7.1 channels; some have 5.1. Here’s what that means: Dolby Digital 5.1, the longtime standard for multichannel audio, has five full channels--front left and right, front center, and two rear--plus a .1 low-frequency bass-effects channel, which is typically sent to a separate powered subwoofer.

Dolby Digital is used on DVDs and digital TV programming. A rival format, DTS, also offers 5.1 channels. DTS is used on some DVD movies and often on recordings of studio and live performances. Dolby Digital EX and DTS-EX are newer formats that add one or two rear channels to the 5.1 setup, for a total of 6.1 or 7.1 channels.

Any receiver with 6.1 or 7.1 channels can also support 5.1 as well as audio formats with fewer channels, including the Dolby Pro Logic family of analog-multichannel decoders. This enables them to transform a two-channel stereo source from your TV into a soundtrack with 4 to 7.1 channels.

To take advantage of true surround-sound capability, you need the appropriate number of speakers in a setup capable of reproducing full-spectrum sound. Some new receivers support Dolby Headphone decoding, which provides a surround-sound experience with standard headphones.

Power output for multichannel receivers is typically 75 to 150 watts per channel. Price: $200 to $500 or more.

THX-certified. Some high-priced multichannel receivers have been certified to meet THX standards. This indicates that they can replicate theater-like sound in a home environment. The higher cost of these receivers generally isn’t worth it unless you have a very elaborate home theater. Power for THX models is typically 100 to 170 watts per channel. Price: $500 to $2,500 and up.

Some models have expanded their repertoire to accommodate newer technologies, such as satellite radio. Models with XM Radio tuners currently outnumber those that support Sirius. (To receive satellite radio, you need an external antenna and must pay an ongoing service fee.)

On higher-priced new models, you might also find support for HD Radio, a free digital form of AM/FM. We expect to see this feature in more models, at lower prices, in the future.

A growing number of models also permit Apple iPod docking. The receiver will charge the iPod, play its audio and video (using the receiver’s remote or console controls), and perhaps show track selections on the console display.

Some receivers have a USB port, allowing you to play music stored on your computer. A few models can route video and still images stored on a computer or on a memory card inserted into a slot on the receiver to a TV.

Another example of versatility is the ability to play music in more than one room. Many receivers have a B-speaker connection that lets you power a remote pair of stereo speakers so you can listen to the same source in a few locations.

A step up from that is multizone capability. That enables you to use different input sources in different rooms—say, listen to the radio in the bedroom while another family member watches a DVD movie in the living room (the main zone). A few high-priced models have three-zone capability. Some receivers provide power for the additional speakers; with others, you might need a separate power amplifier.

Connections matter more on a receiver than on any other home-theater component. A stereo receiver will give you analog-audio inputs and outputs; many will have analog-video inputs and outputs, too, such as composite-video and S-video, and component-video. Multichannel receivers add digital-audio inputs and outputs and analog-video connections. Newer models might have HDMI connections, important if you are planning to use HD video sources, such as an HD DVD or a Blu-ray player. All these video jacks let you route video signals through the receiver to the TV. Some multichannel receivers convert composite-video or S-video input to component-video or HDMI output (still standard-definition). You can select the source on the receiver without having to change inputs on the TV as well.

Multichannel receivers might also have analog 5.1 or 7.1 audio inputs. These accept input from a DVD player with its own built-in digital-audio decoder, an outboard decoder, or other components with multichannel analog signals, such as a DVD-Audio or SACD player. USB inputs connect to a digital media player or a computer.

Controls are another important consideration. Tone controls adjust bass and treble, letting you satisfy your personal preferences. A graphic equalizer breaks the sound spectrum into three or more sections, giving you more control over the audio spectrum. Instead of tone controls, some receivers come with tone presets such as “jazz” or “rock,” each accentuating a different frequency pattern. Often you can also craft your own styles.

DSP (digital-signal processor) modes use a computer chip to duplicate the sound characteristics of a concert hall and other listening environments.

A loudness switch amplifies the highest and deepest sounds to produce richer sound when the volume is set low, and in midnight mode reduces loud sounds and amplifies quiet ones in Dolby Digital encoded soundtracks.

A settings memory, sometimes called “one touch,” lets you store settings for each source to minimize settings when switching between sources. A similar feature, loudness memory, is limited to volume settings alone.

Onscreen display lets you view the receiver’s menus on a TV screen, a squint-free alternative to using the receiver’s LED or LCD display. Switched AC outlets (expect one or two) let you plug in other components and turn the whole system on and off with one button.

Automatic setup and speaker-balancing features are improving, appearing even on lower-priced models. More models also have onscreen setup to simplify the process.
A tape monitor lets you listen to a recording as it’s being made, or patch in signal-processing equipment such as an outboard graphic equalizer.

Automatic or seek-radio tuning searches for the next in-range station at the touch of a button. Most models have a station-preset feature that lets you store 20 to 40 of your favorite stations for easy recall.

To catch stations too weak for the seek mode, receivers also have a manual mode. Direct tuning of frequencies lets you tune to a radio station by entering its frequency on a keypad.

First, don’t assume that pricey brands outperform less-costly ones. We’ve found fine performers at all prices. Points to consider:

How many channels do you want? A receiver with 5.1 channels is suitable for most entertainment today. Down the road, content with 6.1 or 7.1 channels will be more common. A receiver that can support the additional channels will give you some future-proofing but will probably cost more than a 5.1 model. Remember that you need the appropriate speaker setup to get the full effect of 6.1 or 7.1 channels.
If you’re primarily interested in playing music or making an easy upgrade to your TV sound, a stereo receiver might be all you need.

How many devices do you want to connect? Even basic multichannel receivers generally have enough A/V inputs for a CD or DVD player, a VCR, and a cable box or satellite receiver. Mid- and high-priced models usually have more inputs, so you can connect additional devices, such as a camcorder or a digital-video recorder such as TiVo, or a game system.

The number of connections isn’t the only issue; the type also matters. Composite-video inputs, the most basic type, can be used with everything from an older VCR to a new DVD player. S-video and component-video inputs are used mostly by devices that provide better picture quality, such as DVD players, digital-cable boxes, and satellite receivers. To get high-definition TV programming or enhanced-definition output from a progressive-scan DVD player, you must use a component-video input or an HDMI input. If you have or plan to buy an HDTV and an HD DVD or a Blu-ray Disc player, look for an HDMI input.

On a receiver, all video inputs except HDMI require a companion audio input. The basic left/ right audio inputs can be used with almost any device to provide stereo sound. To connect a turntable without the need for a separate phono amplifier, you need a phono input.

To route multichannel sound from DVD players, digital-cable boxes, and satellite receivers, you generally use a digital-audio input. With this input, digitally encoded multichannel sound is relayed on one cable to the receiver, which decodes it into separate channels. The input on the receiver must be the same type—either optical (the more common type), coaxial, or HDMI—as the output on the other device, or you will need a converter. You usually have to buy digital-audio, S-video, and component-video cables, as well as speaker cables. Cable prices vary greatly. We’ve found that expensive brands don’t offer much advantage over lower-priced cables.

What kind of music do you like? Any receiver can reproduce stereo sound. Most multichannel models have digital-signal processing (DSP) modes that process two channels to simulate a sound environment, such as a concert hall. For multichannel music from SACD or DVD-Audio disc player, get a receiver with 5.1 analog inputs.

How big is your room? Make sure a receiver has the oomph to provide adequate volume: at least 50 watts per channel in a typical 12x20-foot living room, or 85 watts for a 15x25-foot space. More power is needed for a huge room, plush furnishings, inefficient loudspeakers, or high volume levels.

Is the receiver compatible with your speakers? If you like to blast music for hours on end, get a receiver rated to handle your speakers’ impedance. Most receivers are rated for 6-ohm and 8-ohm speakers. If used with 4-ohm speakers, such a receiver could overheat and its protection circuitry would shut it down.

Is it easy to use? Look for legible displays and well-labeled function buttons. Some receivers add an onscreen menu, which displays settings on your TV screen. An auto-calibration feature adjusts speaker sound levels and balance to improve the surround effect. Models with a test-tone function help you balance the sound yourself. When deciding where to place your receiver, allow 4 inches or so of space behind it for cables and at least 2 inches on top for venting to prevent overheating.

And if setting up a home theater is a bigger project than you want to tackle, consider professional installation.