Phonograph Monthly Review, Vol. 5, No. 1 (1930-10)

October, 1930, Vol. V. No. I 3 The Theremin The correlation of music from the ether and music on discs Professor Sabaneev, founder of the Russian institute of Musi- cal Sciences . . . anticipates, at least in aim, “the creation of an instrument in which the artistic will would exercise control over the properties of every note, but the realization of the note would be entrusted to the mechanism.” Probabilities are the disappearance of the orchestra and the composition of music direct to the mechanism. The extension of the musical scale is hand in hand with the mechanization of music and the invention of new instruments for this mechanized music. Harry ’Alan Potamkin (in The Phonograph Monthly Review for July, 1930) F ORECASTS such as these have already found factual expression. Not one but sev- eral new instruments of the type Sabaneev anticipated are in the process of development, all of them utilizing that modern Aladdin's Lamp— the radio vacuum tube—the key to the myriad electrical phenomena which have become so es- sential a feature not only of science, but of our everyday life. At least one has progressed far beyond the experimental state, so far indeed as to command the attention of one of the large phonograph manufacturing companies and to win through it production on a commercial scale. The RCA Victor Theremin, the development of Pro- fessor Leon Theremin's “ether-wave musical in- strument" or “Thereminvox," has been on the market since 1929, but for all the publicity it has received and all the enthusiastic endorsements of prominent figures in the music world, the layman still has scant idea of its actual characteristics and potentialities. The Theremin suffers from the aura of hocus- pocus with which it is enveloped in the popular mind. Mysteriously simple in appearance, it looks for all the world like a small writing desk from which a couple of projections extend. The oper- ator plugs it in on the house lighting circuit, makes a few abracadabrian passes in the empty air, and presto, there is music. No wonder an in- nocent old lady at one demonstration voiced the suspicion that a record was concealed within the instrument. Echoes of the birth of the phono- graph, when doubting Thomases examined the machine with the most minute scrutiny to dis- cover the midget or speaking tubes that were surely hidden in it. But like most epoch-making inventions, the Theremin is actually ridiculously simple in prin- ciple, depending, however, on a number of very considerably more intricate and highly developed working parts. The principle is this: Vacuum tubes or “radiotrons," when connected to electric circuits of the proper form, can be made to set up an electric current of an oscillating nature. The Theremin Such a current can be of any frequency of oscil- lation desired. It may be of so low a frequency of oscillation (corresponding to “pitch") that the current will operate a loudspeaker to make the latter sound a musical note. On the other hand, it might be of so high a frequency that the air vibration caused by an associated loudspeaker would be inaudible. It is the latter high frequency electric currents which are used in the Theremin. To produce audibility, two distinct oscillating currents are generated in separate oscillator sys- tems, and then combined to produce a “beat" of audible pitch. The harmonic electric current so formed is amplified and applied to a loudspeaker to produce the air vibration we know as musical sound. No keyboard, strings, taut skin, reeds, or pipes are necessary—as in all other musical in- struments—since the tone is formed electrically. The effect of the hands alone moving through sensitive electrical fields is sufficient to control the pitch, volume, etc., qualities of the tones pro- duced. And with these qualities under exact control—one of course has a fully equipped and expressive musical instrument. The Theremin employs a screen-grid UX-224 Radiotron, three UY-227's, a UX-120, two UX- 171-A's, and a UX-280 Radiotron for power sup- ply. It has two antennae (the straight and curved rods that project from the instrument). One antenna, a vertical metal rod at the top, controls the tone or pitch of the note produced. The other antenna is in the form of a loop at the left side of the instrument and controls the volume or intensity.