Pitch and volume on two axes
Horizontal position sets frequency, vertical position sets gain, both continuously. Nothing snaps to a note, which is the point - a theremin has no frets and neither does this.
Gesture instrument · Web Audio
Theremin
The instrument you play without touching it. Move across the field and the pitch slides continuously; move up and down and the volume follows. On a phone or tablet the motion sensors take over, so tilting the device becomes the performance.
2 AXES
4 WAVEFORMS
MOTION SENSORS
LIVE NOTE READOUT
FX REVERB · DELAY
0 INSTALL
Under the hood
Two continuous axes, no steps
There are no keys and no quantisation. Position maps straight onto frequency and gain, which is exactly why the instrument is hard - and why the note readout is the most useful thing on the screen.
What you get
A real theremin mapping, not a keyboard in disguise
The whole instrument is two continuous parameters. Everything else exists to help you hit them.
Motion control on a phone
On a device with motion sensors, tilting becomes playing. iOS gates the sensors behind a permission prompt, so the app asks once and tells you whether it is running on motion or on the pointer alone.
Four waveforms
Sine is the classic theremin voice and the most forgiving. Triangle is close but brighter; sawtooth and square turn the instrument into something considerably more aggressive and much harder to play quietly.
A note readout that teaches
The current note name, exact frequency and volume are displayed while you play. Since a theremin gives you no physical reference for where a note lives, this readout is how you build one.
Reverb and delay
Both help enormously. Reverb smooths the slides between notes and delay gives a sparse line something to sit in - which is why almost every theremin recording ever made has both on it.
Watch the wave
The output waveform is drawn live beside the field. Combined with the note display it turns an instrument famous for being unplayable into one you can actually make progress on.
Exercises
Four things to try before giving up
A theremin is genuinely difficult. These four make the first hour productive rather than discouraging.
FIND ONE NOTE
Pick a note on the readout and try to hold it steady for ten seconds. Harder than it sounds, and it is the entire skill in one exercise.
OCTAVE JUMP
Move between a note and its octave, checking the readout each time. Building a spatial memory for intervals is what replaces the frets you do not have.
SLOW GLISSANDO
Sine wave, reverb up, drift slowly from bottom to top with the volume steady. This is the sound everyone recognises, and it needs a still hand more than anything else.
VOLUME SHAPING
Hold a pitch and use only the vertical axis - fade in, swell, fade out. On a real theremin the volume hand does the phrasing, and the same is true here.
Getting started
From noise to something resembling a melody
Switch it on
The power control starts the oscillator. Start on sine - the other waveforms are much less forgiving of imprecise movement.
Learn the volume axis first
Before chasing pitch, practise fading in and out on the vertical axis. Controlling when you are audible is what makes everything else sound deliberate.
Use the note display
Aim for a specific note and check the readout. Doing this for ten minutes builds the spatial sense a theremin normally takes weeks to develop.
Add reverb, then try a phone
Reverb makes slides sound intentional. If you have a phone to hand, allow motion access and play it by tilting - it is a completely different instrument.
Specifications
The full sheet
| Type | Continuous-pitch gesture instrument |
|---|---|
| Control | Horizontal axis sets pitch, vertical axis sets volume |
| Input | Mouse, trackpad and touch; device motion and orientation on supported phones and tablets |
| Waveforms | Sine, triangle, sawtooth, square |
| Effects | Reverb and delay |
| Display | Live note name, frequency in hertz, volume level and waveform view |
| Motion status | Shows whether motion sensors are active or the app is running on pointer input alone |
| Requirements | Any modern browser with Web Audio. Motion control needs a device with sensors; iOS requires granting motion permission. |
The oldest electronic instrument, in a browser tab
A theremin has no keys, no frets and no contact. You control pitch and volume by position alone, which is what makes it instantly recognisable and famously difficult. This version keeps the mapping honest - two continuous axes, no quantisation, no snapping to a scale - because a theremin that helps you hit the right note is not a theremin.
What the readout is really for
On a physical instrument you learn where notes are through months of muscle memory. The note name and frequency display shortcut a great deal of that: you aim, you check, you adjust. It will not play the instrument for you, but it turns aimless sliding into deliberate practice.
Tilting a phone is a different instrument
With motion sensors active, the whole device becomes the controller. The gesture is bigger, less precise and considerably more expressive than a mouse - closer to how a real theremin is actually played, and much more fun to perform with.
Part of the GOONS studio
The theremin shares the studio audio graph with the effects, samplers and visualisers, so a line played here can be processed, recorded or visualised elsewhere in the catalog. One subscription covers every app, and a 7-day free trial covers the deciding.
Questions
Frequently asked
How do you play it?
By moving. Horizontal position sets the pitch and vertical position sets the volume, both continuously. There are no notes to press - the instrument is one unbroken glide, which is what makes it expressive and difficult in equal measure.
Can I play it on my phone?
Yes, and it is the better experience. On a device with motion sensors, tilting controls pitch and volume. iOS gates the sensors behind a permission prompt, so the app asks once; a status indicator tells you whether motion is active or you are on pointer input only.
Why is it so hard to hit a note?
Because that is what a theremin is. There is no fixed reference for where a pitch lives, which is why the live note and frequency readout exists - aim, check the display, adjust. Ten minutes of that is worth an hour of sliding around.
Which waveform should I use?
Start with sine. It is the classic theremin voice and the most forgiving of imprecise movement. Triangle is brighter and still usable; sawtooth and square are considerably harsher and much harder to play quietly.
Why does everything sound better with reverb on?
Because reverb smooths the slides between notes and gives a single sustained line somewhere to sit. It is not a crutch - practically every theremin recording ever made has reverb and delay on it for exactly this reason.
Is the Theremin free?
It is part of the GOONS Studio subscription (€9.90/month), which unlocks every app in the catalog, the 5000-sample library and cloud projects. New accounts get a 7-day free trial with full access and no card required.
Keep exploring
Other apps in the studio
Ready when you are
Move your hand and see what happens
The Theremin comes with the GOONS Studio subscription at €9.90/month, alongside every other app in the catalog. Start with the 7-day free trial - no credit card, cancel whenever.
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