So what is a theremin? it is an electronic instrument played without touching it: the performer moves their hands near two antennas, one controlling pitch and the other volume. What follows is where it comes from, what it actually means, three records to hear it for yourself, and the traps to avoid. Get it straight once, and a whole shelf of prog records suddenly reads more clearly.

Where it comes from

The theremin was invented in Russia around 1920 and patented later that decade, named after the inventor who devised it. It was one of the very first electronic instruments, decades ahead of the synthesizer.

Its eerie, wordless wail became a fixture of science-fiction film scores long before rock musicians took an occasional interest in it.

What it does

Because the player never makes contact with the instrument, pitch and volume are shaped entirely by the distance and shape of the hands in the air. This makes it famously difficult to play in tune, and gives it a sliding, vocal, slightly unstable tone. There are no keys, frets or strings — only two invisible fields of sensitivity.

In rock the theremin is a rarity, reached for when a band wants an unearthly, gliding sound rather than a workhorse instrument. It appears more often in the cosmic and psychedelic corners than in mainstream prog, and its best-known rock outings come from outside the genre altogether. Treat it as a special effect with a long history rather than a staple of the style.

Hear it for yourself

The theremin is genuinely uncommon in prog, so the honest picture is a short one.

Led Zeppelin — the instrument’s most famous rock outings came in the band’s live performances, in a hard-rock rather than a prog setting.

The Beach Boys — Good Vibrations (1966) used a related slide-controlled electro-theremin, not a true theremin, but it fixed the sound in the public ear.

Within prog itself the instrument surfaces mostly at the psychedelic and space-rock fringes, as an occasional eerie colour rather than a lead voice. If you want to hear what it does, those scattered psychedelic and space-rock cases are the place to start, and the difference from the electro-theremin is well worth keeping in mind.

Common confusions

It is often confused with the electro-theremin, a different, slide-controlled device used on some 1960s pop records, and with the Ondes Martenot, another early electronic instrument. A true theremin is the contactless one, played on thin air.

As always, the label is a guide rather than a cage. Real records slip between categories all the time, and a term like this one is most useful as a way of hearing more clearly, not as a boundary to police. When the tag and the music disagree, trust the music, and treat the word as a shortcut for a sound you can already recognise.

Go deeper

Back to the progressive rock glossary to keep browsing, or read on about a vocoder, a moog synthesizer, an electric violin. For the records these ideas live in, see the best prog musicians, and if you are just starting out, the beginner’s guide is a gentler way in than any single definition.

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