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The following is from the Journal of the Society of Motion Picture Engineers, 1928. The text is a discussion of the possibilities of using the telegraphone to make "sound tests" on people who were going to be acting in the then quite new field of talking pictures. 1928 must have been the Telegraphone's last gasp, but in that year the only substitute was wax cyllinders (Edison) or disks (also Edison).The problem under discussion was: how to arrange a system so that people speaking into a microphone could hear what their own voices sounded like and how to correct same.

Mr. NORLING: Among the many methods of making sound records for voice tests, I understand a certain producer is using the telegraphone. It would seem to be deficient in the higher frequencies. Is it possible to record by means of the telegraphone a wide enough band of sound frequencies to give high quality? Can you tell us whether the telegraphone wire would lose its record after a period of time or whether the retention of the record would depend on how it is wound up on the spool or container or whether in shipping such records, (if the telegraphone record were employed), rough handling would have any effect, such as erasing or distorting the record? Perhaps Dr. MacKenzie can straighten me out on this.

DR. MACKENZIE: It is not possible to record the sound on the telegraphone with a wide frequency band. With regard to mechanical jars, I don't know quantitatively what this is, and as far as I know, no one has seriously tried to make records for preservation.

Mr. KELLOGG: I should like to ask Dr. MacKenzie if he means the telegraphone as built by the Telegraphone Company and not modified. With higher wire speeds, we might record higher frequencies; and as far as retention goes, I remember an old spool of wire which had been stored about four years still gave some sound, and there was no transfer of record from one wire to an adjacent one.

MR. TAYLOR: It strikes me with regard to the telegraphone that it is one of the easy methods of allowing a person to hear his own voice as recorded, contrary to the others. Without doing anything but rewinding, you can hear it yourself. The psychology of hearing your own voice is very interesting. I think this telegraphone has a very useful although limited field at the present stage of the art. Sorne people speak more falteringly than they realize, and other defects become known to the person speaking and he is able to correct them. Also, while not adapted to high frequencies, these tricks of speech are well shown up without going to the limit on quality. Whereas casting directors cannot form an opinion of a person's abilities in making sound records for the picture business now, they might say it is worth while or out of the question for anyone to come out to Hollywood instead of asking a person to travel 5000 miles on a temporary contract; any telegraphone would do it. The dictation phonograph is fairly well worked out in that direction, but the nuisance of cutting the wax and shaving is one of the points of advantage of the telegraphone.

MR. TUTTLE: At an earlier session, the matter of synchronization at the back and the center of the house was brought up, and it created considerable comment. Last evening, we had a demonstration of the portable Movietone, and a group of us went as far as the entrance of the hotel, about three hundred feet from the screen. We agreed there was no failure of synchronization present at that distance. I think in cases of failure of synchronization, the causes should be looked for elsewhere.

MR. PORTER: I think possibly that is due to the fact that they were using a very small picture. You don,t get it unless you can get the details of the action. A simple mathematical calculation of the time required for sound to travel shows that there must be a lag at some distance. Personally, as I said before,I have been unable to see this unless large heads show the detailed action of the lips. I think that is the explanation of not seeing it in the outdoor Movietone demonstration last evening.

MR. TUTTLE: We based our conclusion on the picture of Gov. Smith, which filled the screen. I admit that physically there is an easily measurable difference. I am questioning the magnitude of the effect as perceived by the senses.

MR. CRABTREE: In order to clarify the discussion, will some one explain the telegraphone. Also, does anyone know about the method of recording which consists in cutting a groove in the film base instead of in a wax record?

MR. TAYLOR :The telegraphone as invented was the work of (Valdemar) Polsen, a Danish engineer. Hardened steel wire of piano quality is used on a spool about this size (indicating), perhaps under 5 or 10 thousandths in diameter. The wire must be hard enough to be magnetized and retain the magnetization. The apparatus is a motor mechanism for winding it at uniform speed although not necessarily so, but at any given instant the speed must be uniform and the magnets must be brought to a uniform magnetic state before recording, and then, an instant later, the wire passes between pole pieces which have the current in them, so that the wire takes the state of a permanent magnet varying in intensity to work up the usual sound curve comparable with any type of phonograph. The wire passes under the poles and by means of the current, with or without amplifiers, the magnetic state is impressed on the wire. The wire must be rewound, and run again under either the same or similar pole pieces, this time the demagnetizing member being left out, and as the state of magnetization of the wire changes, it sets up a flux in the pole pieces, from which it can go to a head telephone direct, which is common to the radio art. The question of possible frequency of registration is similar to the limits of the disk phonograph and speed of the film with the beam of light, and it comes down to the velocity of the wire and nature of the pole pieces. If quality is of more importance, you can speed up the wire and can record the higher frequencies. My own impression is that when the telegraphone came out about fifteen or twenty-five years ago, the quality of speech when I heard it was better than any I had heard on any phonograph, but I am not prepared to make such a comparison today, because many men have been at work on improving the quality of phonographs

. MR. NORLING: Would the speed of the wire be the controlling factor in securing high frequencies or would molecular inertia in the material of the wire itself be a limiting factor?

MR. TAYLOR: I am afraid I am being brought into the position of rooting for the telegraphone, which I am not prepared to do. Magnets wipe out high frequencies, but that is true also for phonograph disk systems. By proper design induction may be made insignificant, although it requires lavish use of current.

DR. CLARK: Do I understand that you get opposite magnetic poles on each aide of the wire? ls there any way of insuring that the wire always travels between the poles with the small magnets correctly oriented in relation to the field?

MR. TAYLOR: That question I raised myself when I heard it, and I don,t know what the answer is. The shape of the pole pieces allows considerable latitude, and, even more important is the fact that the manner of reeling and unreeling the steel wire doesn,t give this. Very likely, experimental work would indicate some defect~ how serious, I don,t know. I have neyer heard of any trouble due to the twisting of the wire. It is not completely demagnetîzed; you muat have a mean from which to work.

MR. KELLOGG: Supplementing this, we had occasion several years ago to play with a telegraphone, as constructed by the Telegraphone Company, who had done good work on it. But the machine was too complicated to be a commercial success. They had two slim magnetic pole pieces which slid along the wire with a separation of about 1/16 of an inch between them. If placed closer than that, the intensity went down. That gives some idea of the frequency limitations; 1/l6th of an inch should not be more than half a wave-length, so that the wire must go pretty fast to reproduce any reasonably high frequencies.

Source: Journal of the Society of Motion Picture Engineers, 1928

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