Contour Synth

A drawing instrument. Pick an instrument, choose the colour you want it to have, and draw: every line becomes a voice in a looping piano roll. Lines play melodies, shapes play chords, and each colour is a different instrument over a soft drum groove. Draw a whole picture, such as a city with a river, and listen to it.

Mixer

Volume for each instrument. M mutes it; S solos it, so you hear only the soloed instruments.

Key Scale Range Octave 0 Tempo 96 BPM Sound Swing Drums Volume Length Detail Paper Line Open

How to play

The paper is a loop: the playhead sweeps from left to right and starts again. Left to right is time, and higher on the paper is a higher note.
Each line plays as one continuous voice while the playhead crosses it: the sound starts where the line starts, follows its shape up and down, and stops where it ends. Where a shape has a top and a bottom (a circle, a wave), both sound together as a chord.
Sound sets how closely the pitch follows the line. Follow line (in tune) glides from note to note within the scale; Follow line (exact) follows the exact height, like a theremin; Notes plays one note per grid cell instead.
The horizontal lines are the notes of the key and scale you choose, so everything you draw stays in tune. The labelled lines are the key note in each octave.
Each colour is an instrument, and it stays selected until you pick another, so every line you draw uses it. Keys, pluck, bell, marimba and chime are struck and ring out; flute, strings, bass and 8-bit hold for as long as the line stays on a note.
Every instrument has its own colour, and you choose it: click the small circle next to an instrument to change its colour, and every line already drawn with that instrument changes with it. Your colours are remembered on this device.
You can draw a complete picture. Buildings, a river, a bridge and a sun are all just lines, and each instrument plays what its colour draws. Press City example to see one. Use the eraser to tidy up, Large or Huge paper for room, and Detail: Fine for twice as many steps across the loop. When many lines cross at once, each instrument plays at most a few notes so it stays musical.
Share link copies a link that opens your drawing, with its key, scale, tempo, colours and mix, for anyone. The drawing travels inside the link itself; nothing is uploaded.
Export WAV downloads two loops as an audio file, rendered with exactly the sounds you hear. Export MIDI downloads one loop with a track for each instrument and the drums, ready for GarageBand, Logic, Ableton or MuseScore. In the Follow-line modes, MIDI notes change wherever a line moves to a new note of the scale.
Open the Mixer to balance the instruments: a volume for each, plus mute and solo. Muted instruments are left out of the exports too.
Save drawing keeps your picture as a file you can open again, and Save picture downloads it as an image. Your drawing is also kept in this browser automatically.
Shuffle draws a ready-made picture to start from and plays it: a beach, mountains, a desert with pyramids, New York, Copenhagen or Sydney with their famous buildings, or an abstract shape in your selected instrument. Keep drawing while it plays and the loop changes as you go. The space bar plays and stops.
Everything runs in your browser with the Web Audio API. Nothing is recorded or uploaded.