The Cine Technician (1953-1956)

January, 1954 THE CINE-TECHNICIAN The Simplex X-L 4-Track Magnetic Sound System currently being installed in key cities across the country consists of two 4-Track Magnetic Sound Heads, eight Magnetic Sound Pre-Amplifiers, two Effects Switchers and a Pre-Amplifier Power Supply. Also included are the necessary sound changeover switches and system selector unit which allows selection of any sound pickup system installed in the theatre. The heart of the system is the compact, filmdriven Simplex X-L 4-Track Magnetic Sound Head. This unit has been designed for simplicity of ininstallation and operation on all modern projectors without making the optical sound head obsolete. Installation of the magnetic sound head only raises the upper magazine 4 inches and also offsets it towards the rear, thus providing adequate head room and front wall clearance. This is particularly important when loading the new heavier 5,000 foot reels. The new magnetic sound head is film-driven, thus eliminating any possible maintenance problems which might be encountered by use of a drive motor or mechanical coupling to the projector. The Magnetic Sound Pre-Amplifiers are plug-in units and mount in compact, easily installed wall cases. The plug-in feature permits the pre-amplifier unit to be changed quickly without disturbing the operation of the others. In operation a separate pre-amplifier is used for each magnetic sound track and the effects track. The function of the Effects Switcher is to electronically control the output of the effects sound track. During these periods when a signal is not present on the effects track, the switcher disconnects the effects pre-amplifier from its power amplifier, thereby eliminating any film noise. The units are plug-in and are readily interchangeable. The power supply is housed in the same wall case with the effects switchers and supplies power to the eight pre-ampliers and the two effects switchers. It also is a plug-in unit, thus providing rapid replacement and ease of maintenance. The Simplex X-L 4-Track Magnetic Sound Head has been carefully designed to provide adequate threading clearances, and with the unit mounted at eye-level, speedy and accurate threading is made possible with a minimum of effort. The " tight loop " scanning system is employed. This is the accepted standard in studio recording systems. The film is threaded through the new magnetic sound head as shown in the illustration and then through the projector mechanism and optical sound head as it would for any type of film. When threading the Simplex X-L Projector, the optical sound drum may be bypassed by threading film from projector lower sprocket in a loose loop to the sound pulling sprocket. Proper film tension in the magnetic sound head is necessary to maintain magnetic tracks in perfect contact with magnetic sound pickup. Film tension is set accurately by the following simple procedure: Open the " UPPER SPROCKET SHOE " and pull the film back over the " DRIVE SPROCKET " until " UPPER and LOWER TENSION ROLLERS " hit their stops. Position film on " DRIVE SPROCKET" and close " UPPER SPROCKET SHOE." When projecting film with optical sound or ordinary single-track sound, only the " UPPER and LOWER GUIDE ROLLERS " in the magnetic sound head are utilised, completely bypassing the magnetic sound pickup. The new composite 4-track magnetic sound film completely eliminates the need for the costly separate sound reproducer previously required for projection of stereophonic sound. It relieves the projectionist of the extra work of handling the millions of feet of film stock now required for separate sound tracks. More important it provides perfect synchronisation of sound and picture, a problem when using separate sound and picture film. The new film may be spliced without fear of losing synchronisation or introducing sound " blooping," however a special film splicer will be required because of the smaller sized sprocket holes. The projectionist should use care in handling the new film and avoid edge damage, since two sound tracks are placed outside the sprocket holes. The film should be kept away from strong AC or DC magnetic fields such as transformers, chokes or strong permanent magnets. A strong AC field will tend to wipe off the magnetic sound on the film while a DC field will cause an increase in noise level. SPOTTISWOODE ON 3-D— Continued is represented on the film by 5/1000 in., say 5 zones of depth represented by 1/1000 in. each or 10 zones of 5/10,000 in. each. This gave some idea of the accuracy required for Stereo equipment. Mr. Spottiswoode turned to editing. The first difference between 3-D and flat films was that 3-D looked very different on a small screen to what it did on a big one. 3-D had to be shot for certain sizes of screen, usually 20 to 30 feet wide. The effect on the 10-foot screen of a studio theatre was quite different. The editor had to bear this in mind. Another aspect to be borne in mind during editing was that an initial adjustments was needed on the part of an audience looking at 3-D. Some people take quite a long time to get the stereo effect. Such people would not be likely to be impressed by quick cutting. He felt that for the time being slower cutting should be used in 3-D. Optical effects in a 3-D film, with its heightened sense of reality, also had to be used with discretion. A very long dissolve might make the audience feel they were present at a seance, and a long fade give the effect of a fog coming on. The effect of fancy wipes was even more horrible. During editing it was possible to do other things. For instance, displacements could be put on or corrected in the optical printer. When the 3-D film finally reaches the cinemas it often encounters the errors in projection which have helped to give 3-D a bad name. He himself felt that the Vectograph system, when it came, was the real answer. It could be described as a stereo sandwich, with the two films printed on top of each other, and the separations built in. Projection was the same as for a flat film. Mr. Spottiswoode concluded by saying that the real possibilities of the 3-D film had not been explored, and it waited for people who could use it. He felt that technicians gave far too little thought to the fundamentals of their technique, they were content to inherit and hand on. His hope was that people would study this new development of the film and explore the possibilities of the medium. The session ended with a showing of Royal Review and an interesting and lively discussion. A. E. J.