A Phonograph that is Always at its Best, Power Transmission by Fluid Waves, and more

R. G. Skerrett
1921 Scientific American  
N OTWITH STAND I�G the much that has been done since the inception of the phonograph to make it capable of more fully and exactly interpreting the .ti mbre and tone of the human voice and divers musical ill struments, the results have been but partway suc cessful. Not only has the phonographic reproduction lacked in the case of some instruments the distinctive characteristics that are theirs, but choruses and orches trations have not been caught by the recording device so that they might be
more » ... ered as we are accustomed to hear them_ Finally, the enunciation of the speaker and the singer has become muffled or indistinct through the processes of ml'chanical preparation of the records and their subsequent audible interpretation. Now, however, a very notable advance has been made in the art, thanks to the labors of Philo E. Remington, of the third generation of that family which has achieved a conspicuous position by reason of the fruits of its inventive cunning. One of the reasons why the run of the reproducers on our phonographs do uot fulfil the expectations of their makers is because the sound waves have not the oppor tunity, owing to the character of the diaphragm mount ing, to acquire their full amplitude. In short, these waves, vital to faithful interpretation of the original source of sound, are more or less deformed or modi fied by the limiting facilities proyided for the propa gation of recording or reproducing vibrations. Mr. Remington has perfected a highly sensitive and elas tically mounted diaphragm and has furnished, at the same time, a vibratory field, so to speak, that gives the sound waves full or undampened play. In this way, individuality of tone is assured, even though there may be many of these seeking to reach the ear. SCIENTIFIC AMERICAN Details of the diaphragm suspension that makes a single reproducer give best results for all tones entire edge, and yet permi ts the mica disk that freedom of vibration which is required to enable it to respond and to transmit the tone waves resulting from any movement of the needle, no matter how slight. Here we find one of the difficulties surmounted which has previously hampered the faithful reproduction of a high soprano voice or any other tone source inducing short wave lengths. Many phonograph reproducers are so designed that it becomes well-nigh a physical impossi bility in assembling them to hold the diaphragm in a way so that they will vibrate evenly throughout their surfaces. In the Remington reproducing device, the insulating quality of the minute points of contact with the steel balls prevents what is termed, in musical parlance, "over-tones." The reason for this is that the tonal values of the reproduction are spnt through the tone-171 nizing the trigger of a machine gun with the blades of the airplane propeller, so that the gun might shoot between the revolving blades. In a sense the rather extravagant claims of a brand new mech anical principle are j ustified, though we strongly suspect that the physicist, had he been all pealed to, would have insisted with equal force that the principle was covered by pre-existing knowledge. "'e are in the habit of thinking of water as absolutely non-compressible, but we must realize that the fact is a little away from this ; that when we apply pressure to this or any other fluid, there must be some reduction of hulk. If there were absolutely no compression in a column of water, a blow delivered at one end of the column could have but one effect-the delivery, instan taneously, at the other end of the column, of a blow of identical force. Even the rupture of the containing pipe at some intermediate point would appear out of the question, were the fluid absolutely lacking in compressi bility. The Constantinescu system, now being commercial ized by a leading firm of British engineers, works through the fact that this compressibility exists. The pipe line is filled full, and blows struck the fluid at one end. These blows, instead of being delivered in stantaneously through a rigid column, cause compres sion waves, as they are called, to traverse the pipe with a perfectly definite velocity approximately that of sound in water ( 4,800 feet per second ) . The actual motion of the water under the influence of these waves is a slight oscillation forward and back as the suc cessive impulses arrive at a given point and pass it by. The obvious analogy is with the ordinary speaking tube, in which the air does not actually flow through the tube, but in which it does act as medium for the trans mission of the sound waves. At the receiving end the wave impulses are pickl'd up by a plunger, which is Rioht: Section of a wave generator developing 10 horsepower, taken through the spherical reservolrli tbiLt maintain the supply of fluid and equalize the forces on the crankshaft , Center: Longitudinal section of a rock drill operated by wave power. L�t: A section through the mechanism that revolves the drill steel The apparatus for driving rock drills by power transmitted by pressure waves through a pipe of water Mr. Remington's phonographic reproducer i s really an evolution of an ingenious loud-speaking telephone transmitter con{'.eived and patented by Captain D. H. 'Wilson, a naturalized citizen of this country, a few years ago. The basic feature of the pioneer idea originating with Wilson was the use of numerous steel balls, arranged in two similar circles placed, respl'ctive Iy, above and below at the edge of the diaphragm. His construction made it feasible to insure an equal pres sure on the diaphragm at all points of support and, at the same time, to permit the disk to vibrate freely. :Mr. Remington became associated with Captain Wilson during the latter's experiments, and immediately real ized how the phonograph could be benefited if the same principiI'S were adapted to that instrument. He promptly determined that the thing for him to do was to mount hi s phonograph reproducer in its own metallic case and then, in turn, to mount this on a series of ball bearings held within an outer case--the purpose being that the inner feature should rest as it were, upon su staining needle points provided for that purpose both at the front and the rl'ar. So far, so good, but extensive research was needful to settle upon some of the vital details. In this quest for the most desirable bearing agencies, he tried out balls of various sizes and different numbers-using miniature spheres of glass, silver, steel, etc. Finally, he fixed upon three silver-steel balls, a quarter of an inch in diameter, symmetrically placed upon one side of the diaphragm and between it and the outer casing of the rl'producer. These balls are separated from the diaphragm by a metal ring which rests on a rubber gasket. This adop tion of the 3-point contact, in combination with the insulating properties of the method of support em pl oyed, makes it practicable to keep the diaphragm in place under a uniform pressure applied around its arm instead of being largely transmitted from the ex terior side of the reproducer through the mass of that arm. In brief, the sound waves are carried through the conduit furnished by the hollow tone-arm and, ac cordingly, follow the line of ll'ast resistance on to the tone-chamber of the instrument whence they issue to the auditor. Both the -tone-arm and the tone-chamber are also sustained by 3-point supports and, therefore, they vibrate with an unusual degree of frl'edom. Power Transmission by Fluid Waves B RITISH contemporaries are having a good deal to say, j ust now, about the application to peaceful purposes of the fluid-prl'sslue system of power trans mission, developed out of the invention of M. Constanti nescu of a leverless and gl'arless means of synchro-Testing leather to see how far it will stretch under a given pull caused to reciprocate. And that is all there is to it, outside of the strictly engineering problems of proper design of the wave-producing apparatus and proper con nection with the machine in which the power is ulti mately to be used. This machine to date has usually been a rock drill, or in some cases a riveting hammer. Here the plunger is used in simple fashion a s a floating p iston, and strikes a blow directly on the shank end of the drill steel or river snap.. Flexibility in use is gained by means of a steel tubing of rather extraordinary character, which can be coiled up in a roll tight enough to be carried over the shoulder, but which presents j oints that are entirely tight to the water, oil, or whatever other fluid may be employed. Coal-cutting and pile-driving equipment operated in this manner is also to be had. A more complete account of the new system appeared in a recent issue of the SCIE:'<TIl'JC AMERICAN MONTHLY.
doi:10.1038/scientificamerican02261921-171 fatcat:ujosnvnv2nbn3il3oqzefsmkhu