One of several optical synthesis devices that emerged in Germany during the 1920’s and 30’s, the ‘Jowiphon’ was a simple monophonic radio-tube based instruments that was operated by playing a hand held light beam across a selenium photocall that in turn triggered an audible voltage pulse generated by a vacuum tube. The Jowiphon was very similar to a design of Wolja Saraga developed at the Heinrich-Hertz-Institut für Schwingungsforschung, Berlin around 1930.
“How amazed, however, was when I was recently with a radioing-meur who was my friend, and he showed me something similar, which at first seemed almost more startling than that Theremin device. He led me into a darkened room with a flashlight in the air – and lo and behold, from a loudspeaker set up somewhere, a music sounded very similar to that of the Theremin apparatus. Here, too, it was only a miracle until Mirmein’s friend explained the technical process.
By exposing a photocell to the flashlamp, an electric current is generated; this is converted into sound vibrations by a certain method, but another, as in the case of the Theremin appliance. The more the flashlight approaches the photocell, the greater the exposure, the electric current becomes stronger and the tones become higher. It all sounds very simple, but it requires a shaken-up amount of knowledge to weld these theoretically remote things into something practical and practical. The inventor has christened his “Jowiphon” sound, which is said to be similar to the Theremin device, but tends toward the string instruments like the violin or cello. But you can also easily create the deepest bass tones like the highest notes of a piccolo. As with the Theremin instrument the tone color and the volume can be changed arbitrarily.
Playing on these devices is no harder to learn than that of other instruments. Their only drawback may be that producing faster results makes some more trouble. As the inventor explained, the Jowiphon, which, like most musical instruments, is unanimous, can also be made into a polyphonic instrument like the organ. The fact that these instruments have not become so popular is largely due to the fact that in Germany two other electric musical instruments have been constructed to a very high degree of perfection, the Vierling Electrochord and the Trautonium.
The Vierling Electrochord is played like a grand piano and allows you to tune to six different tones. The Trautonium is a unanimous instrument that is played by pressing a metal string down on a metal rail. In this instrument, the change of timbre is up to the highest perfection. You can just as well create the sounds of a bass as a clarinet or piccolo. With four instruments you could play a complete string quartet. But it can also produce quite new sounds of surprising effect. The fantastic magic that I felt when I heard the first ether wave music was gone. But I do not feel poorer about it. Despite all knowledge of the technical processes, there is always a remnant of the mystery that one feels again and again when one hears these instruments, which has given us the restraining technique of our century. W. W.’ “1
Uhu illustrated Magazine edition 11.1934/35, May pp 94-95
Joachim Winckelmann. Das “Jowiphon” : [sein Bau u. s. Spielweise] (=Radio-Bau-Sammlung ; Bd. 5). Deutsch-Technischer Buchverlag. Berlin-Lichterfelde 1935