The motion picture projectionist (Nov 1931-Jan 1933)

16 Motion Picture Projectionist March, 1932 will hasten to adopt wax records immediately, this performance will make them sit up and get busy, and either match this quality on film or turn over to the disk. Mr. Ricker: We do not get quite the full benefit of these excellent records in this room. This room lacks in acoustical qualities for a proper appreciation of the magnificent work done. Radio vs. Talkies Mr. Palmer: We are always being told that the radio can produce better sound in the home than talking pictures can in the theater. Can Mr. Frederick give us any information as to whether the quality of the music reproduced here, the fidelity of reproduction, is as good as or better than what the best radio receiver can furnish? Mr. Frederick: I hesitate to hazard an answer to that, as I am not familiar with the characteristics of all radio receivers. The reproduction of many receivers that I have heard was greatly inferior in quality to the reproduction to which we have just listened, but I prefer to let someone who knows more about that particular field attempt to answer your question. I think you have been given a very definite picture of what those frequency characteristics mean by listening with the different filter settings. That is why we played the records with filters in and out so much of the time. One has to hear these things again and again, and even then he would have to check up his cars every once in a while, in order to have an accurate appreciation of what they are hearing. Mr. Maxfield: Was not the reproduction level of the orchestra record as reproduced here louder than would be heard in the center of the orchestra seats in the theater where it was made? I frequently make tests in that theater, and usually sit in the center of the orchestra. My impression here at the back of the room is that the reproduction of the loud parts is louder than they appear to be in the theater, in fact, a little uncomfortably loud. Mr. Frederick: I believe it was. Mr. Carlton: What type of acetate was used for the new record? What method was used for the production of the cellulose acetate from which the record was made? Mr. Frederick: I cannot tell you in great detail. It was a very pure acetate. We obtained it from various sources. Du Pont, for example, has supplied it. Mr. Carlton: Is it molded? Mr. Frederick: Yes, with slightly higher temperatures than are used for most other record materials. A Matter of Taste Mr. Hickman: I believe if the Bell Tele phone Company were to present this entire outfit to an average person living in an apartment, and provide an easy means of adjusting the quality of reproduction to suit his taste, you would find that in general he would eliminate all components having a frequency greater than about thirty-five hundred. If the same person were to listen at a hole in the wall leading to an auditorium holding a good orchestra, the hole being disguised by a loud speaker design, he would tell you that the reproduction was rather good but was deficient in low frequency response. As gramophones are getting bigger and bigger, if you produced one big enough for a man to get inside, and let him speak through a speaker aperture, the observer would tell you that it was pretty good but not quite like the human voice. There has grown up, since the reproduction of canned music, a sort of new standard of what is desirable. Why is it that instinctively we object to what should be the more correct form of recording? I am speaking as a layman, — as an enthusiastic amateur musician. Is it possible that, when the most perfect reproduction has been made, in picking up the sound from a record a high frequency chattering is created which cannot be expressed as harmonics but as a slight disagreeable individuality imparted to the record after, say, a frequency of five thousand, which we would rather have cut out? Mr. Frederick: I do not think that your question about reproducing these high frequencies was directed particularly to me or that you expect me to answer about the tastes of people. And I am not sure that I understand your last question. President Craetree: I think Mr. Hickman wants to know why the frequencies above five thousand seem to annoy one in the home. Recently a friend commended for my radio a new speaker which had a straight curve up to I don't know how many thousand cycles. I obtained this speaker and compared it with my old speaker, which certainly does not reproduce above five thousand cycles. After repeated tests my observation was exactly the same as Mr. Hickman's — that in spite of the high frequencies, I preferred the low ones. The frequencies higher than about five thousand apparently were annoying, and seemed to irritate the ear. From this observation, it seems that straight line reproduction is not always necessary, but depends on the conditions of the room in which the reproduction occurs and on the tastes of the individual. Mr. Hickman: I am not questioning whethei the reproduction shall be linear. I am asking why, when apparently the reproduction is most faithful, we do not find the reproduction of the high frequencies pleasing. I want to know whether some particular form of high frequency distortion is introduced in the pick-up, or later on, which is not in the musical records. H. F. Range and Distortion Mr. Frederick: I do not think that any: body knows enough really to answer your question. And I doubt very seriously if a simple answer could be made if anyone did know enough. However, this point is extremely important. When you extend the high frequency range, if there is any distortion anywhere in the system it may be made audible and distinctly annoying, whereas it was previously inaudible. If the frequency range is to be extended upward a distinctly higher grade of performance must be obtained of all parts of any reproducing system than may seem perfectly tolerable with a lower high frequency cut-off. The loud speakers so far designed aij certainly not perfect. The curves shown in the paper indicate that by far the most jagged and roughest curve of all was that of the loud speaker. It seems reasonable to think that these irregularities, which certainly must mean a certain amount of resonance and "hanging on" of the sounds, must have an effect on the ear. Now, if we could get a perfect loud speaker — and remember, that a perfect loud speaker means that it must be considered in conjunction with the particular room in which it is used — the results would undoubtedly be greatly modified. The characteristics of a loud speaker will be different in one room from another, and may be quite different in different parts of the same room. But placing ourselves at a particular place in a particular room, and having an ideal loud speaker to project the sound, I personally am convinced that we would, as soon as we were used to it, all vote for as broad a range as we could possibly get, and the most perfect or straightline reproduction. The trouble is, as we advance in our halting manner, we often make an improvement which shows up defects which were previously inaudible. Mr. Evans: Is it not possible that the curves may not tell the complete story? The curves that we have seen are for continuous tones — single frequencies — and do not take into account transient effects that may exist. If we knew more about transients, might it not be possible to answer the questions that have been asked here? Mr. Frederick: I think so. At least, it would take us further. Prefers Boom-Boom Mr. Mills: I speak not only as a layman, as some of the others have spoken, but also as one peculiarly inept in music. I have at times attended symphony concerts and orchestral renderings, and suffered from the higher and rasping violin overtones, and from irritating high frequency sounds of brass instruments and cymbals, and it may be that I prefer to listen to a little thirty-five hundred cycle cut-off loud speaker, and interpret its output as music. But it may be that those who have a wider appreciation of music than I, and a greater discernment, would prefer the more nearly complete reproduction which includes the higher overtones. I should like to ask Mr. Frederick whether he would briefly summarize four or five points: What is the increased range of loudness which this new record is capable of providing, over and above the previous loudness range? What is the increase in frequency range? What is the increase in time recorded under normal conditions? And what is the increase or decrease between the cellulose acetate record and the normal shellac, in ground noise, at the various frequencies which are important? Mr. Frederick: The volume range was stated in the paper as being about twenty-five to thirty decibels for most records. I have called them shellac records. They are not simply "shellac" records, but shellac plus a lot of other technic which accompanies it. The volume range with the type of record demonstrated here lies between fifty-five and sixty decibels, according to the best data we have. The improvement is not due merely to cellulose acetate. It is due to a combination of changes. If one of three or four causes, all approximately equal, is eliminated from consideration, the improvement which will have been made in the total effect is, of course, fairly small. Our observations have led us to believe that with the old records the noise du'e to the shellac was somewhat greater than the other noises, but only a few decibels greater. As soon as it was reduced a little the other components of the noise came into •evidence. Regarding the time of recording, I tried to summarize this matter in the paper, but it is difficult to give any simple and definite figure to cover the entire question of playing time. On the older, lateral record, a greater number of grooves per inch was sometimes used. Something has to be sacrificed to do this, but it may be worth while. Edison put out hill and dale records which played thirty or forty minutes. They were not successful because they did not have certain other characteristics which were needed. But as far as playing time is concerned, that is something on which I don't believe you can make any simple statement. Playing Time President Crabtree: For a ten-inch record, how long will a lateral play and how long a vertical? Mr. Frederick: The usual ten-inch lateral record will play three minutes, I believe, and on this type we have thought it good practice to make it play ten or twelve minutes. But if the "game is worth the candle" the time can be made longer. You have to sacrifice something else, however, to do so. Mr. Victor: Is there a relation between frequency and volume? Perhaps the high frequencies carry farther, and perhaps it may be possible to introduce an automatic modulator of some kind for the home that might tone down the high frequencies to a level that would be more pleasing to the ear. Mr. Frederick: Of course it is the easiest thing in the world to get rid of them. The trouble is to get them. High frequencies, I think, are generally found not to carry in distance as well as the low frequencies. A good example of this is furnished by a man making a speech in an open space. As you walk toward him, from a distant point, you first hear the sound of his voice but cannot understand a word. As you get closer, you perceive more of the high frequencies, until, when you get close enough to get the frequencies on which his articulation depends, you can understand what he is saying. This is not simply a matter of how the various components are transmitted but is also concerned with the fact that the lower frequencies in speech, as in music, are usually very much stronger. President Crabtree: What Mr. Victor had in mind was a means of controlling the various frequency components, not to cut them out entirely but selectively to diminish their volume. Mr. Victor: That is right. When a soprano voice comes over my radio I usually reduce the volume. Mr. Frederick: If you should go to a concert to hear a first-class soprano, you would not think of doing such a thing. If you should go to hear a first-class orchestra you would not expect to do it. When we do things of that kind I believe we only try to compensate for the faults of the equipment. Sopranos and Locomotives Mr. Richardson: When I said that the sound was best, according to my judgment, with the seven thousand cycle components included, I did not mean that it was most pleasing, but most natural. A railway whistle, of high frequency, is annoying to everyone. But everyone rather likes to hear a steamboat whistle, which is of low frequency. Some people enjoy a soprano, but they are the exception. But I do not believe that (Continued on page 30)