What is a theremin?
A theremin is an electronic instrument played without touching it. On a traditional instrument, your hands move near two antennas: one controls pitch and the other controls volume. Instead of pressing keys with fixed notes, you guide a continuous tone through the space between notes. That makes smooth slides and gently wavering vibrato part of its character.
You can begin with a single sustained sound. Find a comfortable pitch, hold it, then fade it away before trying another. Accurate melodies take practice because small movements change what you hear. This browser instrument offers a way to explore that coordination without buying a physical theremin.
How hand-gesture playing works
The Free-motion theremin preset is already selected. Start the instrument, allow webcam access, and keep both hands visible. Hand tracking reads their positions while the browser generates sound. Raise your right hand to increase pitch; lower it to descend. Raise your left hand to bring up the volume, then lower it to fade out.
Give each hand some space and face a light source. Keep your left hand steady while moving the right slowly, then reverse the exercise. If the sound stops, check that both hands remain in frame. Camera tracking responds to lighting and visibility, so overlapping hands or fast movements can interrupt a phrase. Headphones help you hear small pitch changes.
What makes this instrument different?
The focus here is independent control with two hands, rather than using a mouse pointer or keyboard to steer a tone. You perform in front of the camera, with continuous pitch movement and a separate volume gesture. It recreates that musical idea, not the antenna response of a hardware instrument; the playing technique will feel different.
This online theremin also shares the site’s four-track loop and recording tools. Capture a short phrase, layer another part, and export the loop audio, or record the camera canvas with the synthesized sound. No account, MIDI controller, or installation is needed. Camera frames are processed in your browser, and recordings download locally. Tracking files must load on your first session, so connection speed can affect setup time.
Read Moog’s guide to the traditional theremin
Theremin questions
Is it free to play?
Yes. The instrument, four-track loops, and recording tools are free to use in your browser without signing in.
Why do I need to press Start?
Browsers require a user gesture to enable audio and your permission to use the camera. The theremin preset is already loaded, so there is no extra mode or preset selection.
Can I play without a webcam?
This version needs a webcam to track both hands. Use a desktop or laptop with a current browser, keep your hands well lit, and allow camera access. It does not offer mouse-only playing.
Can I save my performance?
Yes. Export saves your loop audio, while Record captures the camera canvas and synthesized sound. Files download to your device; the recording format depends on browser support.