You’ve heard the Theremin as a sound-making instrument. But it can be a MIDI controller, as well – an extremely sensitive and expressive one. Continuing our DIY round-up, here are the details in case you’d like to try it yourself.

When we last heard from Sarah Angliss and Spacedog, we were introduced to their creepy Theremin-playing doll Clara 2.0. Now, they’re using the Theremin as an audiovisual controller, triggering audio and video samples from the 1968 film The Devil Rides Out and my personal favorite, a parakeet training record. The result is a new version of the ballad “Willow’s Song” cult classic The Wicker Man (1973). (Wikipedia understands if you don’t.) Here’s a live performance of the result:

I figured readers might want to know more about how to use the Theremin as a controller, so I asked Sarah for more details.

Live theremin AV controller
in Willow’s Song (Hammer sandwich mix)
Here, you’re watching a song featuring Spacedog’s theremin AV controller. The Hammer samples are being scrubbed (i.e. speed controlled) live using the theremin. I’ve devised a Max/MSP patch that enables me to do so – this also scrubs the video live. Mike (in the green tee-shirt) is cueing in the samples as the song progresses.
As the lighting in the gallery wasn’t suitable for projection, we’ve added our usual visuals onto this film, during the edit (sorry – we know that’s cheating). If you want to see the real thing, do come along to one of our live shows. 🙂
This number samples the Hammer classic The Devil Rides Out (1968), mixing it with Jenny’s live rendition of the Willow’s Song from that other British occult classic The Wicker Man (Paul Giovanni, 1973).  The very first sample is from a 1950s Parakeet training record.
The line-up: Jenny Angliss (vocals), Sarah Angliss (theremin and AV scrubber), Ben Kypreos (guitar), Mike Blow (cueing samples), Colin Uttley (camera)
Technical details
All theremins give you a single tone with a varying pitch and volume. Put that into software, such as Max/MSP, that enables you to analyze frequency and volume in real-time and you have the basis of an AV scrubber. I simply hook a continual frequency measurement up to the groove~ control in Max sound and the rate control of a Jitter video to turn my theremin into a highly theatrical AV scrubber that I can use, live, during a song. I do some maths on the frequency measurement so a doubling in frequency, as I go up an octave on the theremin, doubles the speed of the audio and video.
There are various ways to measure frequency in real-time. Fortunately, the theremin creates a waveform that’s highly predicable so it’s easy to use techniques that rely on zero-crossing.
If your theremin has CV out, then you have something very useful – a voltage that you can measure directly and that’s proportional to pitch. You can use this to control just about anything, from lights to music, for instance using a Phidget or Arduino board.
I prefer to steer clear of anything to do with midi because, as a thereminist, I like all the ‘flexible’ (i.e. wobbily and inaccurate) tuning that’s part of the instrument’s character. As midi will quantize your pitch into neat, whole numbers, I think using midi with a theremin is missing a trick. But I realize that’s down to personal taste.
I suppose the hardest and most important bit is to find the right samples to create a really good effect. But then that’s the case, whatever controller you’re using.
Happy thereminininining!
Spacedog UK


Used the Theremin in other ways? Got your own controller scheme? Let us know.