Lexicon 960L owner manual Sound in Space a Short History of Stereo and Surround

960L Owner’s Maunal Using The Reverb Program

Sound in Space: A Short History of Stereo and Surround

The earliest efforts to improve sound reproduction concentrated on broadening frequency response and reducing distortion and noise. But even by the late 1930s, it was obvious that eliminating those barriers to sonic realism weren’t enough. The spatial element was missing.

The first attempt to restore this missing element was stereophonic sound, introduced to the American public via the Walt Disney film Fantasia, in 1941. Its three- channel process could simulate surround directionality by steering signals to speakers around the theater, but was not true surround. Progress in stereo stalled during World War II, but in the early ‘50s, stereo reappeared with the advent of CinemaScope and similar widescreen processes. Shortly thereafter, stereo became available for home listening, first via tape, then phonograph records, and finally, via FM radio.

Stereo added directionality and ambience. The directionality was useful in movies and opera, but otherwise of minimal concern to listeners. Room ambience proved to be stereo’s real selling point for music, helping create the illusion that the listener was in a better acoustic venue than his living room. Some of that illusion had been created in mono days by the inclusion of reverb in the final mix, largely produced in echo chambers (small, hard-surfaced rooms containing speakers to reproduce the original sound and microphones to pick up the added echoes). But in mono, reverb levels had to be limited to avoid muddying the sound. With stereo, the listener could more readily pick out specifically positioned performers from the general ambient background, enabling the amount of reverb to be increased.

At the same time, music was being recorded more and more with close-miked multi-track techniques that did not capture the original ambience, and in studios where there was little or no ambience to capture. This accounts in large measure for the popularity of reverb processors such as the Lexicon 480L.

Even with stereo, some spatial elements were missing. In real life, we hear sounds and ambience from all around us, not from just the front of the room. Adding additional channels at the sides or rear of the room seemed the answer, and surround sound made its appearance in movies and in the home in the 1970s. In films, where it served a dramatic purpose and where a three-channel front speaker arrangement was standardized, it succeeded.

For several reasons, surround sound flopped in the home. There was a confusing array of recording formats, each requiring slightly different playback gear. The few quadraphonic recordings available were split among these formats, reducing the choice still further for listeners who were not equipped for every format. Record producers could not decide whether to use the extra channels to encircle the listener with performers or to provide a front soundstage with surrounding ambience. Most surround setups placed the extra speakers in the rear corners of the room despite the ear’s low sensitivity to lateral directional cues from behind. And many consumers balked at the idea of placing two more full-sized speakers in their rooms. A major reason for the failure of home surround was the recommended four channel format. Without a center channel, Quad sound did not improve the listening area over two channel stereo. To hear a recording one had to be in the "sweet spot", a requirement that was greatly reduced in cinema surround.

Surround’s salvation came from the movies and the development of stereo VCRs. The widescreen films of the 1950s carried multi-track sound on magnetic stripes, but rear speakers mainly carried effects and were often shut off between effects to reduce noise from the narrow, hissy, mag stripes. With the advent of 70mm film, which had more room for soundtracks, mixers began using offscreen channels to carry low- level effects on a continuous basis, adding to the films’ sonic realism.

But most theaters were equipped only for standard 35mm films. In 1976 Dolby Labs introduced Dolby Stereo, a matrix process that encoded surround sound into two-channel optical soundtracks that were compatible with standard cinema projectors. This enabled a single release print to be used in theaters with mono, stereo, or surround sound systems. When these films were released on stereo videocassettes in the early 1980s, the surround information encoded in their two-channel soundtracks was carried over to the home. With the addition of a low-cost matrix decoder and additional amplifier and speaker channels, a consumer could now have surround when watching movies at home via tape and, eventually, via broadcast. Even some made-for-TV programs incorporated surround.

At least for home video, there was now a substantial body of software with a common surround format. There was also general agreement on where speakers should be placed: three in front instead of two, and a pair of surround speakers on the side walls. Home theater began to take off, aided by the arrival of comparatively

5-5