Sounds Like...

https://hackaday.com/2020/10/30/the-theremin-is-100-years-old-celebrating-the-spookiest-of-instruments/

I'm not sure when I first learned about the theremin, but at some point in my young life I learned that to make that spooky, wavering sound/music you heard in the early fright flicks, the sound artists would use a device called a theremin.

I saw a demonstration of one, and it operated with what appeared to be magic. The operator stood by an odd looking electronic device and simply waved his hands around in a sort of pattern, and the device began to sing an eerie song. 

What I had never heard until recently was the inventor, Léon Theremin, might have been a KGB defector who was recaptured and taken to the Soviet gulags where he was forced to work on other electronics projects. Well, I still don't know if all that's true, as some of it remains in dispute. What is true is that his work in the 1920s fed into Robert Moog's work on the Moog synthesizer, which debuted in the late 60s, and eventually led to sampling and the electronic music we take for granted today.

Here's the whole story.

While all instruments are played by a musician, and in that sense you are right in saying the musician is part of the instrument, for no instrument is that statement more true than the theremin. While the musician never actually touches the theremin - another distinguishing characteristic - the theremin operates because of the instrument's ability to sense proximity. The performer's hand acts as the grounded plate (the performer's body being the connection to ground) of a variable capacitor in an L-C (inductance-capacitance) circuit, which is part of the oscillator and determines its frequency. As the thereminist moves his hands in proximity to two metal antennae, the distance from one determines the pitch (frequency) of the sound that's produced, and the distance from the other controls the volume (amplitude). The closer his hand to the pitch antenna, the higher the note; the further from the volume antenna, the louder the note. 

In the early part of the last century the newly formed Soviet government was sponsoring research into proximity sensors. This is simply a device that, by one means or another, senses the presence of a target - perhaps its the vibration of heavy machinery, it might be a motion sensor, on a mobile device, or even a roller coaster. Russian physicist Lev Sergeyevich Termen (known to the West as Leon Theremin) invented the theremin, and began demonstration of it worldwide. He relocated to the United States, and granted commercial production rights on his invention to RCA. 

The stock market crash of 1929 interfered with RCA's introduction of the Thereminvox, but that didn't stop some performers from becoming taken with the instrument, and theremin artists like Clara Rockmore and Lucie Bigelow Rosen toured successfully showing it off. 

The next part of the story remains somewhat in the shadows (a perfect place for such an instrument). In 1938, Theremin either left the United States to return to his homeland, or was captured by KGB-type agents and returned to the Soviet Union where he was put to work in the Sharashka laboratory prison camp in Siberia. About 30 years later, he reappeared, having worked on devices the Soviets were trying to develop in an effort to spy on the United States. 

In any case, you should watch him playing his instrument on an old recording and see if you can feel the Russian musical influence, along with the sounds of sci-fi and horror we've come to associate with it. https://www.youtube.com/watch?v=w5qf9O6c20o

If you wanted a theremin today, you might go to Moog for a kit. After the Second World War, the theremin was relegated to Bob Wood type films, but a persistent interest in it remained among hobbyists. One of them was Robert Moog, who began building theremins when he was in high school. After publishing a number of articles about them, he began to sell kits for assembly by the buyer. Eventually, his fascination with theremins led to Moog experimenting with and building his own groundbreaking instrument, the Moog synthesizer. 

The Moog operates on more sophisticated electronics - voltage controlled oscillators, amplifiers, and filters, envelope generators, noise generators, ring modulators, triggers and mixers - all of which are used to create and "shape" sound, and which can be configured using patch cords (think of the old telephone operator and her two ended plug used to "connect" a call). The synthesizer was played using musical keyboards, joysticks, pedals, and ribbon controllers. Sounds can be recorded and then layered on to one another to create rich music mixes and providing the sounds, or sound-alikes, of many instruments, voices, and assorted other noises. 

The Moog was introduced in 1964, and in 1968 a bestselling album of Bach compositions was released, arranged and played on the Moog synthesizer by Wendy Carlos. Eventually, groups like the Doors, the Grateful Dead, the Rolling Stones, and even the Beatles got into the act, and Moogs hit their stride in the progressive rock era of Yes, Tangerine Dream, and Emerson, Lake & Palmer. 

So now you know. The next time you're curled up with your favorite bad 50s Sci-Fi thriller, and you hear that creeps-up-your-spine sound that tells you the beast is on its way - it probably is. It was a proximity sensor, after all.