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

34 EXHIBITORS HERALD-WORLD April 26, 1930 w SOUND PICTURES Bluebook School . . . Projection Comment By F. H. RICHARDSON BLUEBOOK SCHOOL QUESTION NO. 48. — Is it essential that amplifying tube current be kept at exactly its correct value? What will happen if it be permitted to get too high? Is any benefit derived from using a too-high amplifying tube current? What is the result of a too-low amplifying tube current? Explain just why a too-high current shortens the life of an amplifying tube. MOBILE SOUND I THINK, perhaps, I had better not give the name and address of the writer of the following letter, else he might be deluged with mail. Here is the letter: “I own and manage a small theatre, which I have wired and am running part sound. I am a regular reader of the Herald-World, especially of your own department, from which I assure you I have received ‘lots’ of knowledge on projection and on sound reproduction. Also, I have the ‘Bluebooks,’ which have been very valuable to us. “In the March 15th Better Theatres Section you had an article titled, ‘Wide Film Has Arrived.’ Now, Mr. Richardson, you have witnessed exhibitions of wide film and because you know the business from A clear down to Z, I feel sure you can give the advice I stand in need of. “When using the wide film-large screen, it seems to me it will be very necessary to have the sound coming from varying positions, as when an actor is on one or the other sides of the screen, in order to effect a realistic result. There probably is now some device which accomplishes this, but if so, I have no knowledge of it. Hence this letter. “I have a system worked out which will change the sound from one side to the other, to the center, or wherever its source should be. This is done automatically and continuously throughout the entire program. Its application would require no change in production, as the present system of recording and mixing would be used. It could be attached to any of the present sound reproducing systems, film or disc, and at very little expense. The process of operation would be simple and comparatively inexpensive. “Will you advise me as to whether or no you would consider a system of this sort of any value to the industry.” I perhaps have some grounds for believing that I really do know considerable about projection and sound reproduction and projection. However, here is something I will admit I could not possibly judge the value of, or even make a very intelligent guess. Now, such a method has been considered, I find, but I do not know what was ever done about it. At a guess I would say that if the process be as set forth, namely, simple, easy of application to present equipment and not too costly in either installation or upkeep expense, it should have value. That is my guess. However, I shall put this gentleman Above and below are diagrams prepared by IV. R. Gwynn of Longmont, Colo., to illustrate his answer to Bluebook School Question No. 39. Figures i arid 2 were published with the answer in the April 12th issue, but Figures 3 and 4 had to be left on account of the limitations of space. These diagrams indicate how the amplifier tube must be kept negative in order to give it sufficient leverage to control the high plate potential, and to prevent distortion resulting from partial rectification on the top end of the characteristic curve. Jhplifiod IapulM Distort *4 duo to Partial Root if loatioa aatl roduood ia voliano duo to too Buok "C* Bias '\ -v — ' ! i3?l "3 _/ 1 1 ' I 1 1 1 1 1 1 + r +2 v 3 +4 +£~+.(> > in touch with a company which will give the matter attention and be able to handle it if it seems to have value. AFTERTHOUGHT lU'ARL FRIEDRICH, who in his answer to to one of the questions, recommended a five-hour monthly overcharge, says : “I note that the five-hour overcharge for storage batteries still crops up now and then. When our Western Electric equipment was I installed our first service man recommended the five-hour overcharge every month, but he also stipulated that this overcharge be made at the low charging rate of two amperes or less, which point I forgot to mention in my answer to the question. I have no doubt a lot of people were wondering why the overcharge, : and had in mind a charging rate of anywhere from ten to 20 amperes. Under those cirumstances I can’t blame them for feeling dubious about the extra five hours. However, since the manufacturer of the battery recommends a one-hour overcharge at every sixth or seventh charge, I have adopted this method (the one-hour system) until something else turns up to cause me to change my mind.” All right, Brother Friedrich, but we have to consider only what you actually say. We . cannot possibly know just what you have in mind unless you set it all forth. 35-111111. WIDE FILM A RECENT issue of The Literary Digest I contained an article on an attempt to achieve double width pictures with single width film. Leon Douglas is referred to as the inventor of a mechanism to accomplish this. I am not in the least impressed. Either one of two things would condemn such a plan to me. First of all, one of the obvious benefits of the wide film is that it enlarges the spot area and thus reduces heat per unit area of the film. Any practical projectionist knows the large importance of this, even with the newer shutters. Second, one big curse of motion pictures is what we call graininess, and this shows up < in direct ratio to the magnification. With i wide film, the magnification is sufficiently re j duced so that very little of it is visible. With the narrow film photograph enlarged to wide film picture dimensions, or anything faintly resembling it, the graininess would certainly be pretty awful. To projtct a really well illuminated 35-mm. film photograph to the screen as a dO-foot-wide image — well, gentlemen, rear shutter or no rear shutter, there would be some heat concentrated on that strip of celluloid. This device sounds all very sweet to those who don’t know projection, but those who do will, in my ’umble opinion, pass by on the other side. I