The talking machine world (Jan-Dec 1913)

48 THE TALKING MACHINE WORLD. Eight Ysaye records will soon be announced to the public at $1.50 each; the only trouble Columbia dealers will have with these records will be to avoid being sold out too often. Colombia Graphophone Company Tribune Building, New York THE REPRODUCER AND ITS CONSTRUCTION. Many Enlightening Facts of General Interest to the Talking Machine Dealer, and Others, Set Forth in Technical Description of New Columbia Reproducei The Importance of the Diaphragm and the Care Necessary in Selection — The Creation and Reproduction of Sound a Marvelous Phenomenon and Its Reproduction Is Most Important and Vital. Sound reproduction as applied to the talking machine is to many somewhat of a mystery. Too few have concentrated on this most vital feature of the talking machine, hence the value and importance of an article which appeared recently in the Columbia Record, and which, while referring specifically to the Columbia Co.'s new reproducer, treats in a broad way of its important functions. The data therein has an enlightening and educational value which makes it of exceeding interest, hence its reproduction in part as follows : "Sound, generally speaking, is created by irictional rubbings or by a blow of some kind, the results of which are made manifest by certain vibrations, which in turn disturb the air and set up a wave movement, the air thus acting as a medium of travel for the sound so created. Different sounds are represented by a difference in the number of vibrations per second, with a resulting difference in the form of the sound wave. "Sounds are audible to the human ear from about thirty vibrations per second to 16,000 or 20,000 per second, but in music, sounds are used only for about seven octaves; that is, from forty vibrations per second to a little over 4,000 per second. That is the range of vibration in sound that a reproducer has to reproduce. That means that the little needle-arm on every Columbia reproducer has to make anywhere from 4,000 to 40,000 vibrations or blows on the diaphragm every second and to jump from perhaps 40,000 to 4,000 in the thousandth part of a second. Wonderful as this fact in itself may seem, still more wonderful is the fact that all the different vibrations from the instruments in an orchestra are carried into one wave line on a record. One might suppose that as each instrument has a different tone wave and a different set of vibrations for each note that such a confusion of sound would be set up when they went through a recording instrument as would result in nothing but a conglomeration of noise. That is not the case, however; because when the sound of an orchestra is recorded it imprints on the wax record a single wave line corresponding to the complex sound wave formed. In other words, there is one general sound wave formed of all the other sound waves. That wave precipitates itself on to the diaphragm of the recording instrument and that produces in the wax record a single wave line corresponding to it. This in turn is used in connection with the reproducer in such a way that it throws off the same identical sound that was put into the original wax. "This is brought about by putting a pointed needle in the groove of the finished record and allowing the record to rotate under the needle at the same speed at which the record was made. The wax groove causes the needle-arm to vibrate against the flexible diaphragm and this in turn agitates the air on the inside of the reproducer, but setting up vibrations, corresponding vibrations and tone waves. The air into which those vibrations are shot has only one means of exit, and that is through the tone-arm and horn. "In designing a reproducer amplitude must be considered; that is, the maximum and minimum length of stroke to be made in order to get perfect vibration for long or short tone waves. In other words, for loud or soft tones. "Right here is where we come to one of the most difficult things in designing a reproducer. If the diaphragm is too thick there is not enough elasticity to give a full stroke. The result is a tubby sound. On the other hand if it is too thin we have a raspy or edgy sound. And at no point in the operation of a needle-arm must the diaphragm be subjected to any mechanical strain. The elasticity must not be hampered in any way. Also in order to get purity and volume of tone and freedom from blast the needle-arm itself must be unhampered by any useless enertia. In other words, it must be 'balanced on the pivoting or fulcrum point. The weight of the needle-arm from the needle point up to the fulcrum and the weight of the needle-arm from the fulcrum to the center of the diaphragm, including the diaphragm, must balance each other perfectly. To test this take our new reproducer and put a diaphragm upon it and then pivot it on centers and it will be found that we have practically obtained this balance which is a new feature in reproducers. "One of the most important factors in the new reproducer is the needle-arm, which is nothing more or less than a section of a tuning fork. It is made of one solid, continuous piece of metal and there is nothing in the world that can make a needle-arm so perfect in its vibratory action as a piece of tempered steel for the simple reason that this has all the vibratory qualities of a tuning fork. This is exactly what is required, for we are using this needle-arm for the sole purpose of transmitting various vibrations at wide variations and it must be responsive and sensitive to every vibration that we want to reproduce, whether it be 4,000 or 40,000 a second. The fact that our new needle-arm is made out of one solid piece of dropped forged steel accounts in a large measure for its sensitiveness and also for the clearness and fullness of tone. So much for the method by which the reproducer gathers up the sound. Now for the method by which it disseminates it. Here we use a natural means to transmit the vibrations of the diaphragm to the open air of the room. Therefore every consideration must be given correct proportions. First, the air chamber under the diaphragm next to the tone-arm must be absolutely air tight. To secure this we have designed a moulded gasket cut of solid rubber, instead of using rubber tubing. This rubber carries a little groove near the bottom and in this groove the diaphragm is placed, being carefully centered. This gasket is a little smaller than the inside of the reproducer head so as to still further insure freedom in centering the needle-arm in the diaphragm. "When this gasket is put into the reproducer and a spring ring inserted on top, it makes a perfect packing for the air column under the diaphragm, and in this way we get not only no variations in the manufacture, but, at the' same time, we are assured of the uniform tone quality to every reproducer made. The gasket also serves to insulate the diaphragm absolutely from contact with the metal of the sound box. The diaphragm, of course, must be absolutely free to receive vibrations or the taps from the needle-arm, which, as said before, run anywhere from 4,000 to 40,000 per second. If there is any mechanical strain on the diaphragm it will alter its tone according to the nature of the strain; therefore our diaphragms are assembled first into the rubber gasket perfectly free from all strain. The rubber gasket is then put into the reproducer head, which is a trifle larger than the gasket, so that before the needlearm is attached there is a little movement obtainable from the diaphragm inside the rubber gasket and from the rubber gasket inside the reproducer head. This enables us to assemble our needlearm on the pivot and then let the point of the needle-arm come down in the diaphragm absolutely free in the center hole without putting any strain on the diaphragm. In this position it is then soldered with a small drop of solder. After the assembly is complete the diaphragm lays absolutely free from any mechanical strain due to construction. In this way we get the full swing of the diaphragm with all the loud tones and absolute sensitiveness, for the weaker tones or notes of short amplitude. This center fastening is made possible by the use of a small frommet in the center of the diaphragm which is put on the diaphragm before it is assembled into the rubber gasket and is used to solder the tip of the needlearm to the diaphragm after complete assembly has taken place. "In addition to these improvements we have carefully figured out the weight of our new reproducer in conjunction with the new tone-arm so as to give freedom from blasting in this respect. The weight of the new reproducer being four and threequarters ounces. "One more point in connection with our new reproducer is the angle of the needle. We have found this of great importance, both from a reproduction point of view and from a record wearing point of view. For instance, if a needle is set at 35 degrees it will wear out the record a third faster than when it is set at 30 degrees. Therefore the angle of 30 degrees is now our standard." "TALKER MUSIC" FOR CHOIR. (Special to The Talking Machine World.) Battle Creek, Mich., Feb. 6, 1913. Learning that he would have no choir Sunday because the leader, Mrs. Maude Pike Alden, had resigned, the Rev. William H. Phelps of the First Methodist Church advertised music by prominent New York singers. The pastor used a talking machine. While some of those present went away talking adversely about "canned music" in church, most of them were well satisfied.