Phonograph Monthly Review, Vol. 3, No. 9 (1929-06)

296 The Phonograph Monthly Review June, 1929 How the Sounds Get Into Your Record By the Electrical Process By Experts of the WESTERN ELECTRIC COMPANY (Copyright by The Western Electric Co.) Editor’s Note: The article below appeared in the first issue of The Phonograph Monthly Review, October, 1926. As the early issues of the magazine are now out of print, and as we have had many requests for a simple, authori- tative description of the process of electrical recording that can be understood by laymen, we are re-pritning the article in full for the benefit of our many readers who do not possess a copy of our first issue. F AIRIES live in the forests and if one knows where to look for their rings and knows the magic words he can call them quick as a flash from their hiding places whenever he wants them. There are sounds in phonograph records hiding in the hill-and-dale grooves or in; the hill-side grooves and if one has the records and the magic phonograph he can call them from their disk- homes whenever he wants them. But while in the case of the fairies no one knows how they came to infest the woodlands, every one knows that science put the sounds in phonograph records. In fact, there does not seem to be anything which science cannot do, and the electrical recording of sound waves is only one of its latest and most pleasing achieve- ments. But the average phonograph lover is apt to ap- preciate only those qualities he can directly see and hear—the beauty and workmanship of the cabinet, the quiet non-scratch operation of the particular kind of needle he uses, the perform- ance of a favorite singer or pianist, the blare of a Wagnerian movement, the rhythm of a jazz piece—and utterly to ignore or forget to evalu- ate the marvels of the recording end which have largely made possible his phonograph enjoyment. For while improvements have been made in phonograph instruments, there have also been recent epoch-making advances in developing and perfecting the electrical means of recording music and speech, which have more or less revolu- tionized the principles underlying the whole phonographic art. This work, carried on in the Bell Telephone Laboratories for the Western Electric Company, has been made available for the public through the enterprise of some of the leading phonograph companies. The adage, “The longest way round is the shortest way home”, seems to apply to this new system of electrical recording of sounds as against the former mechanical method. For, theoretically, electrical recording necessitates changing mechanical energy (sound waves) into electrical energy, and then translating this elec- trical energy back again into mechanical units— a long, and on the face of it, a needlessly com- plicated process when one considers that follow- ing the old method the force of the sound waves is used directly to make the grooves on the wax record which constitutes the master disk. But if the electrical process of recording seems less direct than the mechanical, it, never- theless, reaches its destination, and makes pos- sible a more nearly perfect reproduction of the original rendering than otherwise could be se- cured. Furthermore, the process of recording works less hardship on the performers. Formerly the members of an orchestra, the playing of which was to be recorded, had to be re-arranged so cer- tain instruments could secure adequate prom- inence, and had to be grouped, almost crowded, around the recording horn in order to preserve as great an amount of the force of the sound waves as possible. Even so, the weaker instru- ments were in danger of being completely sub- merged. To strengthen the instensity of the waves set in motion by violins, the players had to use “Stroh” instruments which are violins with horns attached in such a way that when the bow is drawn across the strings the bridge vibrates a diaphragm attached to the horn. This horn, of course, had to be directed toward the record- ing horn. Under such recording conditions, the musicians found it difficult to arouse any spon- taneous enthusiasm and as a consequence their playing was scarcely ever noteworthy. Now, however, the musicians sit at ease more nearly in their customary positions and all use the instruments which they would use were they playing at a concert. Conductors prefer to group their various string, wind, and brass choirs to conform to their own conceptions of what will constitute a proper blending of tones. One, for example, may place the horns to the side of the stage, while another may relegate them to the rear. The new method of recording obviates the necessity of disturbing whatever arrangement is desired by the leader. The sounds are picked up by means of two or more high quality microphones in much the same way tones are blended before they reach an audi- ence at a concert. In addition, the time taken for a sound of a given volume to die away after the source has been stopped can be adjusted part- ly through choice of the shape of the recording room and the position in which the curtain and other absorbing materials are hung. All this results in securing the atmosphere or room-tone