Projection engineering (Jan-Dec 1931)

Page 26 PROJECTION ENGINEERING THE RECORDOGRAPH SOUND, DIRECTLY RECORDED Important advance has been made in recent months in the development of simplified equipment for the direct recording of sounds for immediate reproduction. Originally, tin foil was employed to receive the sound wave voice impressions. This was followed by wax cylinders. In recent months the process of recording has been improved so that now celluloid, gelatin and aluminum and its alloys serve this purpose to better advantage. In playing back the record (reproducing the impressions) there is used a needle softer than the material of the record. This is so that the bulk of the wearing away will be on the replaceable needle. At present cactus fibre and bamboo are favored for needles. In the process of recording a turntable is operated by a powerful motor, a feeding device to guide the cutting head in the conventional spiral form, an amplifier and associated speed and volume control. A. playback arrangement can be mounted in the same cabinet, using the same turntable and motor for reproduction. The same amplifier is used. For the cutting head a loudspeaker is substituted, and for the pickup, a microphone. By the movement of a small switch an instantaneous changeover is effected from recording to playback. These outfits are available _ in portable form and one model has associated with it a camera for making moving pictures simultaneously with the sound recordings. An excellent type of recording and reproducing machine is the Recordograph manufactured by G. J. Badgley, 106 West 46th St., New York. AMERTRAN ANNOUNCES NEW SOUND SYSTEM PANELS A new and complete line of AmerTran sound system panels has just been announced by the American Transformer Company, 178 Emmet Street, Newark, N. J. These panels are made for fourteen different applications and may be assembled in various combinations on standard mounting racks to make up complete sound systems for every conceivable requirement. The panels have been designed to permit extreme flexibility so that standard apparatus may be supplied promptly for every purpose and so that the equipment may be enlarged or reduced whenever new conditions make a change advisable, the latter being possible without loss of time and at a minimum of expense. AmerTran panels are of rugged construction and have been designed to meet the most exacting requirements. In all cases the apparatus is mounted on solid aluminum panels of standard (19 inches) width but varying in height in 1 54 inch multiples, the edges being notched to facilitate assembly in the most convenient position on standard mounting racks. The fronts of the panels are scratched-brushed and clear lacquered, and dust covers are provided on the rear to protect apparatus and for the safety of the operator. Knockout boxes for BX wiring are also included on all dust covers to comply with Fire Underwriters' regulations. BEST CARBON SAVER The Best Devices Co., 200 Film Building, Cleveland, Ohio, manufactures the carbon saver herewith illustrated. This permits the projectionist to get at least one more reel from each set of stubs. Made in 7, 8, 9, 10, 12 and 13 mm. sizes. ADVERTISING PROJECTOR The new Auto Cinema sound-on-film advertising projector, product of the Auto Cinema Corporation in collaboration with RCA Photophone, Inc., was demonstrated before a group of representatives of motion picture trade and technical publications at the former corporation's offices in the General Motors building, No. 1775 Broadway on March 11, last. Enclosed within an attractive cabinet which stands about five feet six inches high and which is approximately three feet square, the sound reproducing equipment, comprising the projector, amplifier, motor and six-inch loudspeaker, operates as a unit from power supplied from a lamp socket. The picture is projected upon a transparent screen eighteen by twenty-two inches in dimensions which is located at the top of the cabinet. An outstanding feature of the apparatus is that the film may be projected indefinitely. This is made possible by means of an endless re-winding device upon which the Auto Cinema Corporation has been granted patent rights in the United States and Canada. At the demonstration a number of sound trailers and what might be classified as "short short" subjects were projected expressly for the purpose of emphasizing the importance of this feature in connection with the reproduction of trailers for current and forthcoming attractions in the lobbies of theatres or advertising subjects in hotels, railroad stations or other public places. The sound attachment was developed in the engineering laboratories of RCA Photophone, Inc., to which the Auto Cinema Corporation had taken a model of a silent projector into which the endless rewinding feature had been fabricated. With the only difference being in the size of the objects upon the screen, both projection and sound compared favorably with the sound and projection obtained on standard size RCA Photophone reproducing equipment. VALLEN AUTOMATIC SCREEN MODIFIER As its name implies, the modifier is used in connection with wide size films. E. J. Vallen devoted more than three years time to its perfection before announcing the device to the trade. In construction it is extremely simple and exceptionally rigid. The steel framework is built like a skyscraper and is positively safe. This framework supports and contains all modifying apparatus. The entire unit is electric motor driven, simply operated by a single button, pushbutton station, which provides instantaneous starting, stopping and reversing, and because of the remote control switch, can be controlled from the projection room. Quiet operating electric motors were specially designed for this application. Positive chain drive provides perfect synchronism and noiseless operation. The flameproof velour curtains move smoothly and evenly from the sides and top, contracting or expanding the screening surface at the will of the operator. A truss at the top and battons on either side, to which velour is securely fastened, assure an absolutely straight modifying edge line. Vallen automatic screen modifier can be easily installed without changes or alterations to the stage and occupies no space beyond the screen frame it embodies. The curtains are accommodated at either side on rollers and brailled at the top, making the unit unusually compact. Vallen automatic screen modifiers have been installed in many theatres throughout the country. Complete description of equipment and prices may be had from Vallen Electrical Co. Inc., Akron, Ohio. Best carbon saver. UNDIRECTIONAL SPEAKERS The loudspeaker herewith illustrated is manufactured by The Operadio Manufacturing Company, St. Charles, 111. This is an electrodynamic air column speaker, furnished both in outdoor and indoor types for all public address purposes. 375 WATT-75 VOLT 16 MM. PROJECTION LAMP The Victor Animatograph Corporation, Davenport, Iowa, announces that the new 375 watt-75 volt lamp can be used in any Model 3 Victor cine'-projector that is equipped with the No. 10 Victor lamp rheostat, by having a slight change made in the rheostat resistance. It is only necessary to return the rheostat to the factory as no change is required in the projector. A charge of $5 is made for changing the resistance in the rheostat. After the revision is made, the rheostat can be operated with 250 watt-50 volt, 165 watt-30 volt and 375 watt-75 volt lamps. Also, the rheostat can be disconnected to permit the use of 200 watt-100 to 120 volt lamps in the same projector. Victor thus offers the widest range of lamp interchangeability of any manufacturer in the field. PHOTOCELLS The G-M Laboratories, Inc., announce three new sizes of Visitron type "A" photoelectric cells. These additions bring the number of sizes and shapes of standard Visitron type "A" cells to a total of seven, which constitutes the most complete line of (photoelectric cells manufactured in the United States. There is a G-M Visitron suitable for use in every type of sound equipment manufactured in America. Their high sensitivity, low operating voltage, stability, and long life make Visitrons a valuable component of all sound systems and industrial appliances of every kind in which light sensitive cells are used. THE CUE-METER A versatile and indispensible accessory of prolperly equipped projection rooms is the cue-meter manufactured by the Theatre Engineering Service Company, 1442 Beachwood Drive, Hollywood, Cal. This device indicates the correct time to start the motor and make changeover, and gives cue indications of all other operating essentials. A GOOD AMPLIFIER The Model RV amplifier of the General Amplifier Co., 27 Commercial Ave., Cambridge, Mass., is a two stage a-c. operated voltage amplifier employing one -27 tube and two -45 tubes connected in push-pull. Due to the fact that it employs -45 tubes in the output, it may be used as an output stage where the power output requirements are of a low value, delivering in this respect approximately 4 watts of energy.