March 28, 2008

Quadraphonic Sound

Stupid Question ™
Sept. 12, 2002
By John Ruch
© 2002

Q: What ever happened to “quad stereo,” which was supposed to be the sound of the future in the mid-1970s?
—Brad Browning

A: The sad tale of quadraphonic sound is pretty much encapsulated in the Who’s 1973 album “Quadrophenia.” It immortalized the name of the sound system; it was also notorious as the worst-sounding Who album ever.

Quad sound was basically stereo sound times two. Where stereo uses two channels of sound coming from two speakers, quad used four channels of sound coming from four speakers. The idea was to have a speaker in each corner of the room.

When “stereophonic” albums first came out in the 1960s, most were just mono recordings doubled up onto two channels. During quad’s reign, about 1970 to 1975, it was the same: regular stereo albums doubled up onto four channels.

Few bands actually mixed albums with quad in mind, putting individual sounds on each channel; the Who is one notable exception.

But in its day, it was presumed the world would soon go quad as it had gone stereo before. Some radio stations broadcast in quad. Such bands as Pink Floyd and Emerson, Lake and Palmer used quad set-ups live, with four amp stacks.

And yet, quad died young from the same illness that later plagued video cassettes and compact discs: lack of a standard format, expensive equipment, a variety of technical problems (there was perhaps only one system that truly separated the two rear channels) and little noticeable difference from stereo (mostly because the majority of quad albums were just doubled-up stereo).

The real death blow was that the eight-track tape, the medium on which quad worked the best, itself soon died. It was replaced by the common four-track audio cassette, which had too small a bandwidth to handle quad without distortion.

However, reports of quad’s death—and even its birth—are somewhat exaggerated. The idea of multiple-channel sound actually came from movie theater systems, especially Cinerama’s, and quad went back there after disappearing from the record album market.

The biggest quad formats were “matrixed,” meaning that they encoded the four quad channels together on two stereo frequencies, which could then be cut into a regular vinyl record album. The recording could then theoretically be played back in normal stereo (though there were problems with this) or run through a quad decoder that would separate out the four channels again.

Sound engineer Ray Dolby used the QS matrixing system to create multiple-channel movie soundtracks that also could be played in regular theater mono. Used famously on “Star Wars,” Dolby sound inspired a new wave of multi-channel theater sound.

This is turn has inspired multi-speaker “home theater” systems. And that has itself inspired the release of multi-channel albums in new—and, naturally, conflicting—formats. The main contenders are DVD Audio, which supports up to six channels, and Super Audio Compact Disk, which is six channels.

Perhaps consumers will be less likely to reject a sound system that inevitably will be called sexaphonic.

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