|
A
Slow Start
Dolby
conjectured that applying Dolby A-type noise reduction to the optical sound
track would make it possible for wider frequency response in the theater on
the one hand, and for mixers to record "flatter," less distorted
soundtracks on the other. The result would be - as experiments ultimately
proved - significantly higher fidelity optical sound.
Dolby
then went on to develop an A-type noise reduction unit specifically for use
in movie theaters, which incorporated a special equalizer to widen the
response of theater speakers without their having to be replaced. The
compatibility of movie prints with A-type encoded soundtracks heard in
theaters without a Dolby decoder was tested and judged acceptable, much as
B-type encoded cassettes were being accepted as compatible when played on
non-Dolbyized players. Thus, when lobbying with the film industry to produce
encoded films, Dolby could argue that only one type of release print would
be needed for all theaters.
This
first attempt at involvement with film sound met with only modest success,
however. While the improvement in fidelity was unquestionable, optical sound
was still mono. By this time, superior hi-fi stereo systems had been
installed in so many homes that a significant proportion of the movie-going
public was accustomed to better sound at home than could be heard in the
theater. And since the 1950s, the movie industry had had at its disposal a
different soundtrack method that provided multi channel stereo sound.
With
this alternative method, narrow stripes of iron oxide material similar to
the coating on magnetic recording tape are applied to the finished release
print. The sound is then recorded on the magnetic stripes in real time. The
film is played back on projectors equipped with magnetic heads similar to
those on a tape recorder.
While
many theaters had been equipped for magnetic sound in the 1950s, however, by
the 1970s the expense of magnetic release prints (more than 10 times that of
optical prints), their comparatively short life compared to optical prints,
and the high cost of maintaining theater magnetic equipment led to a massive
reduction in the number of magnetic releases and theaters capable of playing
them. Magnetic stereo sound came to be reserved for a only handful of
first-run engagements of "big" releases each year. By the time
Dolby came on the scene, movie-goers were again usually hearing low
fidelity, mono optical releases, with only an occasional multitrack stereo
magnetic release.
The
formula for film sound success
 Recognizing
that the film industry was not eager for an improved mono format, Dolby
Laboratories went on develop a true breakthrough: a highly practical 35 mm
stereo optical release print format originally identified as Dolby Stereo
and introduced in 1975. In the space allotted to the conventional mono
optical soundtrack were two soundtracks that carry not only left and right
information as in home stereo sound, but also, by means of a matrix encoding
process, information for a third, center-screen channel and a fourth
surround channel for ambient sound and special effects. Yet the new track
was configured to be entirely compatible with mono playback, requiring the
issuance of only one kind of release print.
This
format not only enabled multi channel stereo sound from optical soundtracks,
but also higher quality sound. As with the original mono format, Dolby noise
reduction was used to lower the hissing and popping associated with optical
soundtracks, and loudspeaker equalization was provided to adjust the theater
sound system to a new, wide-range standard response curve.
An
important advantage of the Dolby optical four-channel stereo format was that
prints cost no more to make than mono prints, unlike expensive magnetic
prints. What's more, conversion to Dolby optical was relatively simple and
once the equipment was installed, very little maintenance was required,
particularly when compared to magnetic stereo playback systems.
The
Dolby film program
Although
the potential for the new stereo optical format was far greater than the
original mono Dolby format, success did not come overnight. Whereas Dolby
noise reduction for professional tape recording was a relatively
straightforward add-on and could be marketed as such, Dolby's new film
format required significant changes throughout the film sound
record/reproduce chain, and thus throughout the film industry.
Dolby's
ultimate goal seemed simple enough: to profit from the manufacture and sales
of a new range of theater sound processing equipment. However, for that to
happen, film producers had to be educated in the benefits of the new format.
Sound mixers had to be brought on stream with new techniques. Distributors
had to be reassured that stereo release prints were compatible with mono
theaters. Theater equipment suppliers had to be educated in system
requirements and installation procedures. And theater owners had to be
convinced that investing in the new equipment would pay off at the box
office. As a result, it was necessary to implement and staff a film sound
program, not unlike the licensing program, that could reach out to all these
disparate segments of the film industry.
The
multi-faceted, international program that resulted incorporates several key
elements. These include Dolby film sound consultants who assist at the mix
of films slated for release with soundtracks utilizing Dolby technology
(today there are Dolby consultants in every film production center in the
world). Dolby has also established offices in New York and Los Angeles to
further assist the U.S. film industry, and it regularly conducts training
courses to train equipment installers and technicians in the ins and outs of
Dolby theater sound equipment.
As
with other software, Dolby builds the encoding equipment necessary to
produce soundtracks incorporating Dolby advances. This equipment is not sold
outright, but is leased to film companies and studios, with Dolby
Laboratories maintaining title. This policy, along with the quality control
applied to film soundtracks by Dolby consultants, Dolby's manufacturing
theater sound processors to the same standard as the encoding equipment, and
the various Dolby training programs, helps to ensure the high quality
presentation audiences have come to expect from "Dolby" on the
marquee.
While
this program was being developed, one further element was needed to ensure
Dolby's lasting presence in the film sound field: audience awareness. The
watershed year was 1977, with the release of two immensely popular films
that were recorded with the new Dolby technology: "Star Wars"
and "Close Encounters of the Third Kind". These
blockbusters were exhibited in just enough theaters that had invested in the
new Dolby equipment for audiences and industry alike to sit up and take
notice. Marketing research soon began to show that audiences would go out of
their way to theaters exhibiting in the Dolby stereo format, and avoid mono
presentations of the same films.
While
"big" films were the early adopters of the new Dolby technology,
it wasn't too long before films of all types began to be released with
stereo optical soundtracks. The result was a profound change in the
movie-going experience. In 1976, when you went to a movie, chances were that
it would have low-fidelity, mono sound; multi channel hi-fi stereo was a
rarity. Today, however, when you go to the movies, chances are it will be presented with multi channel stereo sound. That is attributable
directly to Dolby Laboratories and its film sound program.
|
Further in 70mm reading:
Part
1
Processors
Milestones
Technologies
Format codes
In
70mm Dolby
Internet link:
Dolby Laboratories
|
