Exhibitors Herald and Moving Picture World (Apr-Jun 1930)

fi4 Better Theatres Section April 12, 1930 HELP PREVENT FILM FIRE AND BUCKLING WITH THE NEW IMPROVED CHICAGO CINEMA FILM COOLING SYSTEM— ELIMINATES SOUND DISTORTION DUE TO WARPAGE OF SOUND TRACK The simplest device yet manufactured and the easiest to install and operate on Simplex and Motiograph heads — no drilling, replacing of parts or remodeling of your old head when installing. Does not occupy any necessary space. Will not interfere with film threading, framing or any adjustments or repairs while in operation. No exposed moving parts. Does not add to the cost of repairs, as it is not necessary to take off any parts when repairing head. Lengthens life of aperture gates and asbestos heat shields with the consequent reduction in cost of replacements. Film temperatures are reduced considerably when using the CHICAGO CINEMA Film Cooling System, thereby lessening fire hazard, and also lengthening film life by preventing buckling and warpage. It eliminates sound distortion by preserving the sound track. This system consists of a scientifically designed centrifugal impeller driven by a Universal motor and mounted on an aluminum base which is readily attached to any head. On the Simplex head, this device slips into grooves provided for stereo attachment. Write for new bulletin CHICAGO CINEMA EQUIPMENT COMPANY 1746 No. Springfield Avenue, Chicago more information about it would be given later. Here it is, illustrated with a few diagrams : In Figure 1 is shown the circuit in the new Audak pickup. When the oscillator (A) is in the exact magnetic center, no flux, it is claimed, can traverse it. Inoperative, this is the ideal position of the oscillator. But it is just in such cases that the oscillar is most sus ceptible to flux changes. Briefly, the effect is one of the increasing tendency toward distortion, according to Audak engineers. They declare they have overcome the difficulty by changing the position of the oscillator, which is accomplished by the method indicated in Figure 2. Coil B is supplied an audio-frequency current. The leads from C are connected to headphones. The position of A is then varied until no sound is heard in the headphones — and that is the position at which the oscillator should be placed, the engineers point out. In the theatre, the pickup may be “tuned” by a simpler method, as indicated in Figure 3. The needle is tapped gently on either side with the finger nail. If the oscillator is off the magnetic center, the two sounds will differ in pitch and volume. If the instrument is in “tune,” the sounds on both sides will be the same. If the right side sound is “thinner” than the other, the tuner provided should be turned a little to the right, while the reverse of this movement would correct the left side. “A Baby Dynamic” • A new speaker, intended for use with exponential horns and designed to be powerful enough for public address systems, weighs only six and a half pounds, is but four inches thick and has a maximum diameter of five inches. It has developed by the Racon Electric Company. The diaphragm is made of light metal attached by cloth suspension. The casing is of magnetic steel of high flux density, selected to effect a concentrated magnetic field with a minimum of material. According to the manufacturers, it is capable of an output of 10 watts (without distortion). S’Renco Equipment • Sound equipment for disc reproduction has been added to the line of the Universal Film Screening Company. The apparatus has been marketed under the name of S’Renco Disc Reproducing Equipment, and although some of us may hesitate at the pronounciation of the first word in the title, we must admit that it has the virtue of being also the name of a man (the head of the company) who has been in the projection field for 20 years. S’Renco equipment includes two 18inch turntables, pickups, quarter-horsepower motor-units, two Wright-DeCoster speakers and horns, two Webster amplifiers, a fader (a new type employing button contacts instead of those of wire