the Magnetic Age

By the 1950s the film industry felt threatened by the rapid growth of television. They started promoting widescreen formats (television had adopted the aspect ratio of 1.33:1, the same as movies). Together with enormous screens and high resolution prints stereophonic sound was introduced.
The most used widescreen formats were:

They all had their own (magnetic) sound system, except for VistaVision that used the Perspecta Stereo system. Several 70mm formats such as Ultra Panavision (M-G-M) and Super Panavision 70 used a Todd-AO-compatible sound system. Both were used only for limited roadshow presentations; most releases were 35mm anamorphic reductions with optical monophonic or CinemaScope-compatible 'magoptical' soundtracks.

Few exhibitors were willing to install the expensive equipment that was needed for stereophonic sound reproduction and maintaining the equipment, especially the magnetic heads, was costly. The cost of applying magstripes to the prints and the relatively short lifespan compared to optical sound together with an overal decline of the movie-industry in the late 1960s and early 1970s resulted in fewer and fewer releases.
Athough magnetic sound provided superior sound quality, only a handfull of major releases a year had magnetic stereophonic sound and only for a few weeks (as the prints wore out) and then it was back to low fidelity monophonic sound.

In the mid-1970s the sound system on 70mm releases was replaced by a variation by Dolby with improved noise reduction and a slightly altered configuration. (see the Rise of the Dolby Empire)

In 1974 a new sound format saw the light that literally shook the world: Sensurround, which sent, at certain points during the presentation, high-volume low-frequency sounds to specially designed sub-woofers, located in the theater. The format, developed by MCA, was used for only a few releases of which "Earthquake" (1974), "Midway" (1976), "Rollercoaster" (1977) and "Battlestar Galactica" (1978) were the best known.


previous chapter: ...And then there was sound.


next chapter: the Rise of the Dolby Empire



Cinerama was the first real widescreen format: it had 3 seperate strips of film to create its very wide view (146).
As for the sound, early tests with 6 optical tracks on a fourth 35mm film didn't provide the necessary results. So, when the system was presented to the public the sound system consisted of a magnetic recording on a seperate fullcoat film, that ran at the same speed as the 3 film strips. It featured 7 tracks, that fed 8 speaker channels: 5 behind the screen and 3 in the auditorium (2 at the sides and 1 in the rear). Track 6 and 7 could be switched manually between stereo surround (and no rear channel) and mono surround plus rear surround.
The three film system was very expensive to install, required a large staff to operate (3 men for the projectors and 1 for the soundtrack) and the need for additional projection boxes resulted in a loss of seating capacity. These caused the operational costs to be circa half of the gross box-office turnover.
It debuted in 1952 with "This Is Cinerama", which was nothing more than a showcase. M-G-M's "How The West Was Won" (1962) was the first feature film presented in Cinerama; it became the studio's third highest grossing movie. Also in 1962, there was "The Wonderfull World Of The Brothers Grimm". The last production to be shot in 3-strip Cinerama was the 1963 showcase "The Best Of Cinerama".

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CinemaScope : Developed by Fox as a competitor to Cinerama, CinemaScope used only 1 filmstrip for the picture. To achieve a widescreen view the picture was squeezed on standard 35mm film to half its width using an anamorphic lens. During projection the picture is expanded back to its normal aspect using a similar lens.
Fox also realized that a multichannel, stereophonic soundtrack was necessary. Research done by Bell Telephone Laboratories into stereo optical sound, Disney's Fantasound process and Cinerama's magnetic system formed the basis of the CinemaScope sound system. At first the 4 tracks - left, center, right and surround - were located on a seperate magnetically coated film, but the company foresaw that exhibitors would be extremely reluctant to install a costly and complex system with double films and therefore they switched to a magnetically striped print.The aspect ratio had to be reduced and also the sprockets were made smaller to accomodate the 4 magnetic tracks. The screen channels were located on both sides outside the sprockets and on the left between the sprockets and the picture area. The surround preview CinemaScope magnetic printtrack was located on the right between the picture and the sprockets and was half the width of the others. The sound on this track was controlled by a pilot tone to disable it when it wasn't used because the narrow track was rather hissy.
At first Fox released only stereophonic prints but exhibitors were reluctant to install the necessary equipment (magnetic heads, amplifiers, multiple speakers and wiring). So Fox made prints in preview CinemaScope magoptical printoptical mono, single track magnetic and original 4 track magnetic. Releasing films in 3 different formats proofed to be too expensive and Fox chose a combined magnetical/optical print where the mono track was a half width. M-G-M used for its CinemaScope releases one optical track with the Perspecta Stereo sound system.
CinemaScope premiered in 1953 with "The Robe". Later Panavision adopted the anamorphic process and was the magnetical/optical soundtrack replaced by an optical Dolby Stereo one. (see the Rise of the Dolby Empire)

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VistaVision : Although the negative was a normal 35mm film that ran horizontally and has a picture area twice the size of a normal (vertical) one, very few release were done in horizontal running format. Most releases were done in vertical running 35mm reduction print.
The studio that promoted the VistaVision, Paramount, wanted stereophonic sound but exhibitors were very reluctant to install new equipment. Also, magnetically striped prints were rather expensive so they chose the cheaper Perspecta Stereo sound system.
It debuted in 1954 with "White Christmas" and in 1955 there was "Strategic Air Command" but it was never really succesfull (because exhibitors needed to install a second pair of projectors to run the horizontal film stock of the Large Area version). VistaVision was ressurrected in 1975 when Industrial Light + Magic used it for visual effects work on "Star Wars" and it is still in use today for that purpose.

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Todd-AO : Mike Todd, who had worked on Cinerama, realised the flaws (cost and convenience) in the 3-strip system and together with the American Optical Company he developed a single camera system that used 65 mm filmstock. Release prints were 70mm wide: the soundtrack was located on the extra 5mm. Initially it ran at 30fps (Cinerama did 26fps) to provide a more flicker free image but later features were shot at 24fps which made it easier to make 35mm CinemaScope reduction prints.
As with Cinerama a multichannel stereophonic sound system seemed necessary. At first it consisted of a 6-track and 1 control track magnetic soundtrack located on a seperate 35mm film. It ran at 90' per minute, considerately lower than the 140.25' of the projector which caused problems with synchronizing the sound preview Todd-AO printand the picture. There was also the fear that exhibitors would reject double systems. So they developed a system where the 6 tracks were located on the preview layout Todd-AO70mm print using magnetic stripes. The 6 tracks fed 5 speakers behind the screen and there was one track for the surrounds. There was also the possibility to apply Perspecta Stereo to the surround channel to create a 3-channel directionality for certain scenes.
It premiered in 1955 with "Oklahoma!" and the next year "Around The World In 80 Days" was released. For general release 35mm anamorphic CinemaScope-compatible reduction prints were used with a magoptical soundtrack (4-track magnetic and a half-width optical mono track) or a full-width optical mono soundtrack.
Todd-AO's magnetic 6-track sound system was the standard for all 70mm releases until 1977 when Dolby released their 6-track system. (see the Rise of the Dolby Empire)

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Technirama was developed by the Technicolor Corp. They modified the VistaVision-system: They reduced the aspect ratio to make room for a 6-channel soundsystem and added a 1.5x anamorphic squeeze.
The first Technirama production was "Monte Carlo Story", produced in Europe in 1957 and it was one of the few films to be presented in 8 perf horizontal system. Most releases, though, were vertical 35mm anamorphic CinemaScope-compatible reduction prints with a magoptical soundtrack (4-track magnetic and a half-width optical mono track) or a full-width optical mono soundtrack.
In 1958 Disney decided they too wanted a 70mm format for roadshow presentations. So together with Panavision Inc. they developed Super Technirama 70. The frame of the horizontally running Technirama negative was stretched vertically thus taking the space initially intended for the magnetic stripes. Using optics made by Panavision, the picture was printed on 70mm film and a 6-channel magnetic soundtrack was applied. Super Technirama 70 was compatible with Todd-AO.
The first movie produced in Super Technirama 70 was "Solomon and Sheba", released in 1959.

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Perspecta Stereo was really a pseudo-stereo sound system. On a (optical) monophonic soundtrack control signals were encoded. These signals, consisting of sub-audible tones of 30, 35 and 40Hz, were picked up by an integrator unit that turned up the gain on right, left or center speaker channels, creating rather simple directional effects. The sound was limited to frequencies above 63Hz to avoid the control tones being heard.
Perfecta Stereo was easier and quicker, thus cheaper, to mix than a true stereo system like CinemaScope although installing the integrator and other necessary equipment cost nearly as much as a real stereo setup. The soundtrack was also completely compatible with standard monophonic reproduction equipment, if exhibitors didn't want to install the system.

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Sensurround, developed by MCA for the release of "Earthquake" in 1974, underwent several modifications with every release. The general idea, however, stayed the same: low-frequency noises and rumbles, played at high-volumes through specially designed speakers, support the normal soundtrack of a movie.
In the original setup, used for "Earthquake", a digital pseudo-random noise generator delivered low-frequency noises and rumbles that fit the waveform of the earthquake in Sylmar in 1972. These rumbles were played at 110dB to 120dB and ranged from 16Hz to 120Hz. The low end of the frequency range was limited to 16Hz because lower frequencies would damage buildings by structural resonance. (However, some theaters were still damaged.)
Two control tones, one of 25Hz and one of 35Hz, which were recorded on the print steered the noise generator. For the 1974 setup the mixing of the standard audio program into the Sensurround-speakers was triggered by 1 tone. The other one made the noise generator produce the rumbles. Variation in volume of the control tones changed the level of signals sent to the Sensurround-speakers. There was a 60dB volume increase in the main speakers when both control tones were present at the same time.
Several different versions of the prints were available: mono optical, 4-channel magoptical and, in Europe, 70mm 6-track. With mono optical the control tones were mixed into the main program. The magnetic tracks of 4-channel magoptical provide the main stereo and the optical track contained only the control tones. With the 70mm 6-track versions the control tones were recorded on the Center Left and Center Right tracks. As the Sensurround-system provided the surround-like effects the surround speakers of magnetic installations were disconnected.
In 1976 for the release of "Midway" a extensively changed system was presented: Sensurround Mod II. The biggest change was that the low-frequency sounds were recorded on the print instead of produced by the external noise generator. The control tones sytem was also modified: 1 controlled the Sensurround speakers in the front of the theater, the other the ones in the back. A type of noise reduction and compression called DBX was applied on the soundtrack, on top of which the rumbles came. The low-frequency sounds were not compressed with DBX so when the soundtrack was played through the control box the rumbles would be give a double expansion, as they weren't 2:1 compressed by DBX. The optical track wasn't made compatible with the 'Academy' standard which increased the dynamic range to 80dB and resulted in a frequency response of 16Hz to 16kHz. Because of DBX the Sensurround Mod II prints weren't compatible with standard playback equipment.
"Rollercoaster" (1977) was also released in Sensurround Mod II but changes were made during mixing: the Sensurround speakers were also used for music and real low-frequency sounds, recorded on rollercoasters, were used instead of synthesized ones.
"Battlestar Galactica" used Sensurround Mod III and "Zoot Suit" was shown in Sensurround+Plus, which was merely the use of DBX noise reduction on the 4-track mag prints for extremely high fidelity, without any rumble. It was also supposed to use LightSurround, an in-auditorium synced light cueing system, but no installations were done.

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