Kathy Hinde

25 January, 2020



I met Andrey Smirnov at his apartment where he has a number of instruments from his archive. On entering, I had a look at the Emiriton and one of Leon Theremin’s Theremins from the 1960’s. However, the main purpose of the visit was to examine Theremin’s early ‘drum machine’ – the Rhythmicon. Andrey has restored this instrument so it is possible to actually play it. Here is a video of him demonstrating it.

Having read much about the Rhythmicon in ‘Sound in Z’, it wasn’t until I watched it in action (and had a go on it!) that I fully appreciated how it functions, and the inventive methods employed.  The first key is a low note which repeats once every cycle; the next note is higher and twice every cycle; the next, three times and higher still; and so on up to 15 notes. The instrument uses two spinning discs with concentric patterns of holes cut into them (one disc for pitch and other for rhythm), combined with lamps and photodetectors. When a key is pressed, a lamp lights up which is in line with a ring of holes in the discs. The rhythm disc lets light through at timed intervals, (the overall tempo or ‘bpm’ can be adjusted) and the pitch wheel spins much faster allowing a specific intensity of light  to pass through to the ‘rhythm’ disc hole. A photodetector picks up the signal and generates an analogue sound based on the intensity of light it receives, and when it receives it. The photodetector generates different amounts of electrical current based on how much light lands on it, which alters the pitch heard. Andrey has modified this Rhythmicon for playing live, and has installed a dedicated photodetector for each key, and replaced the lamps with LEDs (he has kept all the original parts so it can be returned to Theremin’s original version). The most fascinating discovery was the method Theremin used to get light to a single photodetector (because, he only had one) and to determine which note is being played. How is this possible? – surely he needs 15? Andrey showed me Theremin’s beautiful solution to this problem. An array of small fragments of mirror – each directing the light beam to a single photodetector from a different angle, which could be read accurately and therefore it was possible to determine which key was being played. This is a great example of innovation – solving a problem in a new way due to lack of resources. So inspiring. Work with what you have and find creative solutions – there is no excuse !!

Front and back pictures of the Rhythmicon and the little mirror sculpture – ( it’s art… )


Diagram of the layout of the holes in both discs of a 16 note Rythmicon (the one Andrey showed me has 15 notes). It shows the principle though.

Rhythmic discs

It was no surprise to learn that Andrey built his own synthesisers in the 80’s. Here he is with one of them, (and the Rhythmicon).


Towards the end of our discussion, Andrey mentioned that Theremin had explored acoustic sonic phenomena whist at the Acoustical Laboratory, Moscow Conservatory including experimenting with a series of Helmholtz resonators tuned to specific frequencies. This really fascinated me, as I have been exploring resonant frequencies in a number of installations, for example: ‘Tipping Point‘ and ‘Vocal Resonances‘. Picture below of a Helmholtz resonator and a reel of steel wire that was used to record magnetic sound onto, which Theremin also experimented with.