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4-channel sound done right—and expensively

technofile  by al fasoldt

Columns and commentaries in a life-long dance with technology
 

Simple gray rule


4-channel sound done right—and expensively
 

By Al Fasoldt

Copyright © 1993, The Syracuse Newspapers

Four-channel sound used to be a joke. Back in the '70s, JVC of Japan and our own CBS Records tried to convince millions of music lovers that we could get four separate sound sources out of a long-playing record.

They were right; we got four separate sound sources, and they all sounded terrible. Their slogan should have been, "Bad Sound All Around." Luckily, four-channel sound quickly disappeared into the junkyard of audio history. But now it's back again, under a new name—"surround sound." And this time, the electronics engineers have done the job right.

In a more primitive form, surround sound has been around for quite a few years. This kind of surround sound used a circuit developed by the Dolby company—the same outfit that came up with the universal method of getting the hiss out of cassette tapes.

I've had a Dolby surround-sound adaptor hooked up to my video-theater hi-fi system for two or three years, and it's done a pretty good job. When I watch a movie, many of the sound effects come right out of the back of the room.

But while the standard Dolby surround-sound system can provide some exciting effects, they aren't very realistic. There are technical reasons for this, but the main point is that true surround sound should be exactly that—sound that surrounds you. Regular Dolby surround-sound circuitry gives you a ping-pong effect—first you hear something from the front, then the back, then the front again.

That's not the way it is in real life, unless, of course, you're watching a table-tennis match.

So Dolby's engineers came up with a new version called Dolby Pro Logic. It's a smart device, recreating the sound-all-around sensation that you get when you are in the middle of all the action. Dolby Pro Logic can only do its job properly when the videotapes and laser discs you rent or buy have sound tracks encoded with Pro Logic signals, but this is becoming fairly common.

What's more, even standard stereo TV broadcasts sometimes have Pro Logic encoding. And as a bonus, I've even heard a few compact discs that have the same surround sound built in, too.

For the last month or so I've been listening to Dolby Pro Logic audio through a new audio-video receiver loaned by the Carver Corp. It's the Carver HR-895, which has four stunning features besides Dolby Pro Logic. They are Sonic Holography (a way of improving the realism of the sound over some kinds of speakers), a center-channel audio signal, a vastly improved FM tuner circuit that let me pull in stations more than 80 miles away, and two remote controls—a regular one with a zillion buttons and a credit-card-size remote with just the basic controls.

The HR-895 has only one drawback—the price. It lists for a whopping $1,600. It's not hard to see where part of that megabuck cost goes, since the Carver has four powerful amplifiers and a sophisticated switching system that lets you record on one VCR while you are watching a tape from another one, but a receiver that costs as much as eight typical CD players is plainly out of the reach of most of us.

On the other hand, if you have not yet purchased a hi-fi system and can afford the price of entry, the Carver HR-895 would make an excellent combination unit. It has all the functions of an amplifier, tuner, control center, audio-video switching box and surround-sound adaptor—and does it all without a fuss.

The sound quality from regular hi-fi sources is first-rate, especially when the Sonic Holography circuit is switched in, but it's the Dolby Pro Logic that captivates me every time I turn this big receiver on. The latest video movies recorded with Pro Logic pass my "blind listening" test easily—the soundtracks still seem realistic even when I close my eyes. Try that with regular movie soundtracks, and you'll probably find the sound falls flat without visual cues.


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