Perspecta stereophonic sound is now available to you at a new low price | Read more at in70mm.com The 70mm Newsletter |
| Written by: Stelma Electronics, Incorporated. Brochure, 1954 | Date: 01.04.2025 |
 The new important development in sound that has been adopted by M.G.M. Paramount and Warner Bros. (recorded on all product released from now on) Perspecta Stereophonic Sound is now available to you at a new low price a new field-tested and proven perspecta sound integrator manufactured under license of perspecta sound inc. By Stelma electronics incorporated Designers and manufacturers of quality motion picture sound equipment Go to PDF Technical Bulletin Number 1, September 1954 Go to PDF Technical Bulletin Number 2, September 1954 Go to PDF Technical Bulletin Number 3, October 1954 Go to PDF Technical Bulletin Number 4, November 1954 Go to PDF Optical Directional Sound Test Film (ODS-1) Go to PDF International offers and price list Go to Perspecta Sound and the Fairchild Perspecta Integrator Go to Perspecta Stereophonic Sound Basic Principles Go to The Paramount VistaVision Process STELMA'S engineering and production efficiency means lower cost to you What is Perspecta Sound? Perspecta Sound is the latest development in stereophonic sound reproducing equipment for the motion picture industry. Now, with Perspecta Sound, standardiza-tion of stereophonic sound is at last possible throughout the entire industry. How does Perspecta Sound Work? The idea on which Perspecta Sound is based is amazingly simple. The sound track is identical to the optical sound track that the producer and exhibitor have been using for years with the exception that three low frequency tones (too low for human hearing) are combined on the film along with the speech and music. The low frequency tones are "directional-volume" signals which are varied according to the stereophonic effect desired by the producer. How Does It Operate In The Theatre? In the projection booth the film is passed through and scanned by the conventional standard sound head. The mixture of speech, music, and "directional-volume" low frequency tones are fed into the Stelma Perspecta Sound Integrator. The Stelma Integrator is the heart of the system. It responds to the low frequency "directional-volume" signals and continuously directs the speech and music into any or all of three separate channels, varying the volume and focusing the sound at the point of dramatic emphasis on the screen to produce the stereophonic sound effect desired by the motion picture producer. | More in 70mm reading: Perspecta Sound and the Fairchild Perspecta Integrator Perspecta Stereophonic Sound Basic Principles The Paramount VistaVision Process in70mm.com's page about VistaVision in70mm.com News Peripheral Vision, Scopes, Dimensions and Panoramas in70mm.com's Library Presented on the big screen in 7OMM 7OMM and Cinema Across the World Now showing in 70mm in a theatre near you! 70mm Retro - Festivals and Screenings |
 The Stelma Perspecta sound integratorStelma stereophonic sound equipment is designed for peak theatre performance by the same audio engineers who produce the rugged communications equipment used by all U S Armed forces. A Complete Assembly In One Money-Saving, Space-Saving Unit . . . mounted and pre-wired with interconnecting cables in a standard open rack as illustrated above. Rack is 25" high, 21" wide, 12" deep, and is suitable for floor, wall or ceiling mounting. or Separate Unmounted Units of the Stelma Integrator and Power Supply and/or Stelma Sound Track Selector Panel (with or without fader) for use in standard amplifier racks. Tested and Approved by Perspecta Sound Inc. and C. R. Fine, Inventor | |
 The Stelma integrator responds to the low-frequency tone signals and channels the sound to give the desired stereophonic effect.Mr. Exhibitor: HERE'S HOW YOU BENEFIT WITH THE STELMA PERSPECTA SOUND SYSTEM: Prints Widely Available More and more prints in Perspecta Sound will be available standardization is on the way! Producers are enthusiastic about the low cost and simplicity of this new sound system. And incidentally, you can run conventional single track optical prints through the versatile Perspecta system or Perspecta prints through the standard single optical system. It's a Fully Compatible System .. This new stereophonic sound system is the only system that is completely compatible with existing sound equipment. It offers you important advantages: No changing of standard equipment or sound heads. No complicated installation (or installation charges). No costly maintenance problems. No possibility of sound track de-magnetization. No manpower problems. No special care, switching or watching. Includes Automatic Changeover ... The Stelma Integrator switches automatically from Perspecta Sound to single-channel optical sound and back! Now you can mix newsreels and Perspecta Sound prints without manual switching. Play a print with Perspecta Sound track and stereophonic sound results. Play a single channel optical print (a newsreel, for example), and the Stelma Integrator switches the sound over automatically to the theatre center horn. Two-Way emergency Insurance ... By using the Stelma Perspecta Sound equipment you are doubly insured for emergency service. If one of the three channels becomes inoperative, the sound is transferred automatically to the center horn. Furthermore, Stelma provides you additional protection with its Sound Track Selector Panel. A flip of a switch makes available your stand-by single channel optical system. And since Perspecta prints can be run on your conventional single channel equipment, additional insurance is available in emergencies. New Low Prices .. Every theatre can afford the Stelma Perspecta Sound Integrator at its present low price. And just one Stelma Sound Integrator is all you need in your booth regardless of how many projectors you use! | |
 Installation Of The Stelma Perspecta Sound IntegratorIf your theatre is equipped with multiple-track magnetic sound equipment, the components marked in black on the diagram are already in your booth. The two white areas represent the only additional equipment needed (and the Stelma Sound Track Selector Panel is not always required). The Stelma Perspecta equipment required can be obtained as separate units or in a completely assembled package, pre-wired and mounted in a 25" open rack suitable for wall, floor, or ceiling mounting. Installation time . . . and installation costs . . are cut to a minimum. If your theatre is not presently equipped for stereo-phonic sound, the wonders of Perspecta Stereophonic Sound are now available to you at a price you can afford. The only equipment required in addition to the Stelma Perspecta Sound Integrator are the extra power amplifiers and horns. There are no expensive projection equipment costs. Stelma Engineering Cuts Your Costs. HERE'S ONE EXAMPLE HOW The usual method of controlling the volume of multi-channel sound in a theatre is to use a multi-gang volume control (fader). Stelma engineers, however, have made available in the Stelma Perspecta Sound System a single master volume control (fader). A product of Stelma's cost-conscious engineering, the Stelma single fader is designed to save the exhibitor need-less expense. It replaces the previous method of volume control (the multiple-gang fader) with a money-saving single fader that controls the volume of all Perspecta channels through a single internal connection point in the Integrator. This results in lower output distortion . . yet equipment cost is slashed by two-thirds. And your installation costs are also cut ... since the single master volume control comes completely pre-wired in the Stelma Integrator rack. | |
| A word about Stelma, Incorporated You can measure the reputation of Stelma's engineering and production skill by the exacting standards of its present customers, among whom are: U. S. Navy U. S. Air Force U. S. Signal Corps R.C.A. Communications Western Union American Telegraph and Telephone Co. Western Electric Co. International Telegraph and Telephone Co. The new Stelma Perspecta Sound Integrator is sold through established theatre equipment dealers. WRITE, WIRE, OR PHONE TODAY Stelma, ELECTRONICS Incorporated 389 LUDLOW STREET, STAMFORD, CONNECTICUT Designers and Manufacturers of Quality Motion Picture Sound Equipment NILES CHRISTENSEN, EXPORT REPRESENTATIVE, P.O. BOX 728 SUMMIT, New Jersey | |
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