Motion Picture Herald (Jan-Mar 1932)

32 SYNCROFILM The Silent Sound Head Silence until the music starts or an actor speaks — that's Syncrofilnn. Syncrofilm will not produce a sound of any kind that is not recorded on the track. This absence of background and outlaw noises makes the amazing clearness of Syncrofilm highly productive at the box office. People rather expect electric sound equipment to gurk sometimes — radio has accustomed them to it. The startling freedom from racket in Syncrofilm-equipped houses brings favorable cash comment from pleased repeat patrons. Syncrofilm is guaranteed to satisfy you. Give it a good long trial. Watch receipts and listen to show after show. You'll see for yourself that the quality of performance stands up — keeps on bringing in profit. Start the trial today. Name your projection machine so we can quote properly. WEBER MACHINE CORP. 59 Rutter Street Rochester, N. Y. Export Office: 15 Laight Street, New York City Cable Address: Romos, New York SYNCROFILM Give Your Audience "COMFORTABLE HEARING" ACOUSTICAL PERFECTION assures easy sound reception and contented patrons; the condition which reacts favorably at the Box Office. Faulty acoustical conditions may be analyzed without resource to expensive checkings by electrical recording means. Provide clear audibility at every seat. For information write to S. S. SUGAR Acoustician 11 West 42nd St. New York, N. Y. Better Theatres Section In all the apparatus described above, one common form of trouble will be found to be an imperfect connection, not in the part itself, but at its terminal. This, of course, is easily repaired. Sockets give trouble chiefly through failure to make firm contact with the tubes they carry. In most cases the tension of their contact prongs can be adjusted, and the prongs themselves cleaned and polished smooth, without any need for factory repairs. Occasionally spare prongs can be obtained, and replacing these will be found cheaper than replacing the entire socket. The difference in cost, however, will seldom be great enough to make such a course worth bothering with. An amplifier, rectifier or motor speed control box will contain, in addition to the parts mentioned, wiring, switches and meters. Burnt-out or short-circuited wiring should be replaced by wire of the same size and of equally effective insulation. The replacing wire should always be run exactly the same way as the original wire. In some apparatus the exact position of the wiring is important for perfect results, and especially for preventing some types of amplifier or rectifier circuits from creating a hum in the sound. Switches are easily replaced and are too inexpensive to justify repair. Meters are not subject to projection room repair. Voltmeters may be removed from the circuit, ammeters must be shorted. Signal lamps of appropriate rating make a roughly effective temporary substitute for meters. Rejuvenating Tubes TUBES OF THE thoriated tungsten type of filament can be "rejuvenated"— sometimes rejuvenated over and over again. The process consists in heating the filament, for about ten minutes, at roughly 20% more than the rated current, after which the tube is kept burning for several hours at normal rating. No plate or grid voltage is supplied to the tube during this process. February 13, 1932 Equipment for rejuvenation consists of a socket of proper size and a source of filament current. In addition, a rheostat — or resistance-and-switch arrangement — is necessary in order to vary the filament supply between normal and 20% above normal Theatres using tubes of the type susceptible to this process should be able to cut their tube replacement bill by as much as 50%. Speakers The dynamic speaker consists principally of a field winding and a speech winding, the diaphragm of the speaker being attached to the latter. It is the speech winding that causes almost all the trouble to which speaker units are subject. It burns out, or it becomes separated from the diaphragm, and in either case the receiver will not function. Storage Batteries Storage batteries on occasion may be repaired by a local battery station, which will rent the theatre other batteries until its own have been restored to usefulness. It should only seldom be necessary to resort to that extreme. Storage batteries that show signs of weakening can be cared for in the theatre. The battery service station has no equipment other than a charger — the theatre also has a charger. If the batteries can have reasonable intervals of charging while they remain in the theatre, there is no occasion for sending them to an outside station for service. As batteries age, it may become necessary to dump out the sediment which collects on the bottom. It may also be necessary to renew the electrolyte, but unless a great deal of it has been spilled in the process of taking hydrometer readings, this should not be the case. Either form of attention can be given in the theatre. It will not often be found advisable to replace dead cells in a three-cell battery. Replacement of the entire battery will usually be found to be less troublesome, and in the long run, to cost no more.