Sound In Space: A Short History Of Stereo And Surround - Lexicon 960L Owner's Manual

960L
SOUND IN SPACE: A SHORT HISTORY
OF STEREO AND SURROUND
The earliest efforts to improve sound reproduction con-
centrated on broadening frequency response and reduc-
ing 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 stereo-
phonic 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 re a p p e a red 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 direction-
ality was useful in movies and opera, but otherwise of min-
imal concern to listeners. Room ambience proved to be
stereo's real selling point for music, helping create the illu-
sion 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, large-
ly produced in echo chambers (small, hard - s u rf a c e d
rooms containing speakers to re p roduce the original
sound and microphones to pick up the added echoes).
But in mono, reverb levels had to be limited to avoid mud-
dying the sound. With stereo, the listener could more read-
ily 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 succeed-
ed.
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 quadra-
phonic recordings available were split among these for-
mats, 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 sound-
stage 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.
major reason for the failure of home surround was the rec-
ommended four channel format. Without a center chan-
nel, 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 devel-
opment 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 video-
cassettes 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 sur-
round speakers on the side walls. Home theater began to
take off, aided by the arrival of comparatively affordable
large-screen TVs, Dolby Pro Logic, which added logic
steering to the basic matrix decoder, and Home THX cine-
ma, which imposed common standards on home sur-
round equipment. Pure audio recordings with matrix sur-
round encoding began to appear, although when repro-
duced with Pro-Logic or THX matrix decoders these
recordings could be disappointing.
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