So you want a decent home stereo system--but still need to be able to afford a decent home? For those of us who aren't millionaires, an A/V receiver can be a godsend: It does the work of several components and any one of a number of respectable models can be yours on a budget.

An Audio/Video receiver (a.k.a. "Surround Sound receiver") is an amplifier, pre-amp, and tuner all in a single chassis. This serves as your control center, the very heart of your home theater system, with components wired into it and speakers wired out. It offers switching capabilities for all of your audio sources which are then passed to the amplifier section of the receiver, as well as switching for video sources, routed to your television. The amp provides four channels of power if it is a Dolby Pro Logic unit (left, right, center, and one rear), or five channels of power (left, right, center, and two rear) if it is a Dolby Digital model. The Dolby Digital model will also pass the bass information through to a subwoofer. Everything you do with your system-speakers or headphones, music or movies-is controlled by your receiver, the only component you cannot do a thing without.

Years ago, receivers were built with analog tuners which were costly to produce and were therefore too pricey for many consumers. Integrated amplifiers removed the tuner while keeping the amp and pre-amp, resulting in a much more popular unit. But with the advent of digital technology, the entire tuner circuit can be incorporated into one chip, making a full-fledged receiver so affordable that integrated amps have become almost obsolete. Stereo (or "hi-fi," audio-only) receivers are potential dinosaurs as well, progressively replaced by A/V receivers. Even if you do not buy your receiver with video applications in mind, that option is yours at a minimal additional cost. And sooner or later, most consumers will take advantage of its full audio and video capabilities.

Besides its duties as an amplifier, an audio/video control center (the modern, multimedia descendant of a pre-amplifier) and an AM/FM tuner, the A/V receiver offers a Dolby Pro Logic surround sound processor, which no home theater should be without. Pro Logic is the system whereby multi-channel surround is encoded and decoded onto and off of the two-channel stereo format. Dolby Digital decoding, meanwhile, is the step-up audio standard for DVD, capable of discretely utilizing all five channels plus the sub, for "5.1-channel surround." Digital surround sound is an absolute "must" for truly serious movie viewing. The increased realism you will hear, in details both subtle and staggering, is the reason so many people have become home theater devotees in recent years. Once a high-end feature, Dolby Digital has become an affordable option on most A/V receivers. Many models also add the necessary hardware to process DTS ("Digital Theater Systems") at a modest extra charge. This rival 5.1-channel format, arguably more dynamic as a result of its strict encoding and mastering standards, provides another major playback choice for your listening enjoyment. But remember that there's only a short list of DTS CDs, and nowhere near as many DTS-encoded DVDs as Dolby Digital has to offer.

Today's receivers also feature sound field processing circuitry that can create a variety of effects to make the most of your discs, tapes, and broadcast signals, converting your living room into everything from a concert hall to the local Cineplex. Its "phantom" mode can even compensate for the lack of a center speaker. The test tone generator sends pink noise through each of the speakers so the listener can match the levels of all channels, either with a sharp ear or with the help of a meter purchased at the local Radio Shack. Speakers can vary quite a bit: The less efficient a loudspeaker, the more power you will need from your amplifier to produce equivalent volume. And without proper levels, the surround experience would be distracting instead of convincing.

Set-up is a breeze: It's just one box, requiring only one power supply and a few interconnects. And you'll have no worries about matching, say, the pre-amp's processor loop with a surround sound processor. Once installed, its benefits will become obvious. You could fit your whole system - DVD player, VCR, receiver, and monitor - all on a TV cart, if so desired. A single remote control (most come with one, and most of those are unified remotes) will give you power over your sound system. All this, without breaking the bank!

The first thing to consider in choosing a receiver is power: How much power do you need? But we can't answer that without posing a few other questions: Do you live in an apartment or house? Big or small? Thin walls and whiny neighbors? Do you crank up rock music and watch movies with lots of explosions, or do you savor the classics with a glass of Chianti in one hand and a Kleenex in the other? How well is this going to fit in with the rest of your system; for example, how many watts can your speakers handle? Your present set-up probably says a lot about your listening habits, and those habits will affect your decision.

What do you want this thing to look like? Do you crave more buttons and lights than the bridge of the Starship Enterprise? Something more like the monolith from 2001? Afraid you'll need a degree in integral calculus just to figure out how to play a CD? Do you view remote control as merely a convenience or a fundamental way of life? You'll discover a wide price range, as more and fancier features, plus certain nameplates, raise the stakes. Other key features to consider include a headphone jack; the number of radio station preset buttons; the number and type of inputs, outputs, and speaker binding posts; and of course, the amount of wattage per channel in the stereo and surround modes. Front panel-mounted A/V input jacks are particularly handy for quickly and temporarily patching in a video camera or adding a second VCR for dubbing, and top model receivers have even begun to offer component video switching for high-end video gear. Another cool feature is midnight mode, which allows you to get a rich blend of highs and lows, while not disturbing your neighbors or sleeping family members.

A good surround sound receiver can deliver on the promise home theater audio, and serve as the cornerstone of your entire A/V set-up. With lots of makes and models to choose from, finding the ideal match should be a painless procedure, providing a simple solution to even the most complex array of source components, loudspeakers, and wires.