Movietone Bulletin (September 1928)

MOVIETONE. BELLE TIN Published in the interest of the Movietone Projectionist by Fox CASE CORPORATION 460 WEST 544 ST. EW YORK VOLUME I, No. 36 ESD aos SEPT. 8, 1928 Horn Control Panel N order to realize the best repI roduction it is possible to secure from any movietone film, strict attention should pe given to the setting of the horn control panel. In general, the best setting of this panel will differ for different types of numbers, news reels and most short numbers requiring a different horn setting from that found desirable for scored pictures. In your instruction book, under “Rehearsing,” will be found Sheet No. 92, paragraphs 4 and 5 and Sheet No. 93, paragraphs 5, 6, 7 and 8 which give as much general information with respect to horn settings as will apply to all theatres and to all types of reproducing equipment. Under the heading, “Setting-Up,” will be found Sheet K-190 upon which the installation engineer, after testing the acoustics of the theatre, should mark the dial positions to be used as the “A,” “B,” “C” horn settings. In most theatres the “A” setting is used very seldom with movietone film. The “B” setting is usually recommended for news reels and most short subjects. The “C” setting is usually recommended for scored pictures. Occasionally there may be a short subject consisting mostly of orchestral or band music and the “C” setting may be more suitable in this case. Certain music scenes shown in the news reel can sometimes be improved by a similar change from the “B” to the “C” setting if the change is made quickly. It is very important, however, to return immediately to the “B” setting upon completion of the music shot. If the music shot is of short duration, it is better to use the “B” setting throughout rather than interfere with what may follow by too slow a return to this setting. When making these changes in horn settings, great care should be observed not to leave the horn dial switches in such a position that the brush makes contact on two studs of the switch simultaneously. If any one of these switches, including that controlling the monitor horn, is left thus short circuiting two contact studs, a short circuit on the output of the power amplifier will take place and poor quality reproduction will result, the magnitude of the effect depending upon which studs are thus short circuited. In order to be sure that the horns are performing in a satisfactory manner, the projectionist should at least once each day, in the absence of the audience, test each horn separately, making sure to see that it is performing normally and properly. Watch Sprocket Idlers Movietone projectionists should be very careful about the adjustment of sprocket idlers. They should be set about two thicknesses of film away from the sprocket, closer than that is likely to cause trouble; further away most certainly will. Also be very sure that both ends of the idlers are equi-distant from the sprocket. Failure in the last will almost certainly make film “climb” in the sprocket. Projector Optical System Note: In this series I shall refer you to your Bluebook of Projection, because of the fact that it would consume a prohibitive amount of space to print all the various diagrams and text to be found in the references. OVIETONE projectionists of course should and must pay very close attention to the proper care and adjustment of the sound apparatus. That is, of course, obvious, because unless it be properly cared for and adjusted it will not function properly and if it does not function one hundred per cent., then it follows that the results as heard by the audience are not what they should be. However, it must not for a moment be forgotten that the sound you are projecting is in synchronism with a motion picture, and unless that, too, is placed upon your screen at its highest possible value, the whole thing must inevitably suffer, and your work be discredited just to the extent of the failure. I therefore have decided to talk with you concerning the projection optical system, faults in which not infrequently cause large and entirely unnecessary light loss. In fact, it is not at all uncommon to find a remedial condition in the projector optical train which is causing as much as a twenty-five per cent. light loss, the condition existing because the projectionist either is unable to secure proper lenses, or lacks the knowledge necessary to efficient selection and adjustment of the various elements of the projector optical train. It would be an altogether too long story to tell of all the various possible projector optical train (Continued on last page, Col. 3)