Surround Sound Spurs Interest in A/V Receivers

In a few years, the audio receiver--the staple of home audio units--may be as obsolete as record albums.

It’s being replaced by the A/V (audio/video) receiver, which has been taking an increasing portion of the market since its introduction in 1986, largely thanks to the surging popularity of the home-theater concept. Bob Weissburg, Sony’s vice president of hi-fi marketing, predicted that 50% of the receivers sold this year will be A/Vs.

Traditionally, the audio receiver--a unit combining a tuner (radio), an amplifier and a pre-amplifier--has been the hub of the home audio system, which includes speakers and a turntable, and maybe a tape deck and a CD player.

But this is the video age. With VCRs in more than 70% of the nation’s homes, combining audio and video systems was inevitable.

That’s where the A/V receiver comes in. It’s really just a more comprehensive audio receiver. It does what a conventional audio receiver does--but it also sports a greater number of output and input jacks for video sources and decoders for surround sound.

The surround-sound capability is what is triggering much of the A/V receiver’s popularity. These units have the circuitry to decode the Dolby stereo sound that comes encoded on videotapes, laser discs and some TV broadcasts.

To get the basic surround-sound mode, Dolby Surround, the consumer must hook up four speakers to the A/V receiver--one on either side of the TV set and two in the rear. The result is realistic, you-are-there sound, the kind heard in a movie theater. The viewer gets a sense of being in the middle of the action, with sounds moving around and emanating from the rear.

There are two kinds of A/V receivers. One has a basic surround-sound decoder, for a four-speaker hookup. It is discounted as low as $300. The more expensive A/V receivers--at least $600--are equipped with a Dolby Pro-Logic processor, which can provide sound to five speakers--including a crucial center channel.

(Some Pro-Logic units sell for about $450, but the manufacturers have cut corners, like not providing an internal amplifier for the fifth speaker or providing only minimal amplification for the rear speakers.)

The extra speaker in the Dolby Pro-Logic setup is usually placed under the TV. With just four speakers and basic surround sound, the dialogue often seems to be coming from an inappropriate location--spoiling the realistic effect. But with Dolby Pro-Logic, the fifth speaker is the source of the dialogue and other effects that properly seem to come from the center rather than the sides or rear.

The more expensive A/V receivers provide extra surround modes that add extra realism, duplicate the acoustics found in places like concert halls and night clubs, and provide simulated surround sound when the consumer is using non-stereo video sources.