project Technology › Doodle Wave
Draw-your-own-waveform synthesizer
A synthesizer I originally made during a Stanford summer workshop at CCRMA. It's MIDI controllable and capable of 4-note polyphony. You use it by drawing an arbitrary waveform on the LCD with your finger or a pen. There's no delay between the drawing and synthesizing — you can even draw the waveform while you're playing the MIDI controller.
When you draw on the screen, most of the pixels aren't updated (depending on how fast you draw). To solve this, I erased pixels in front of where the pen was moving and added rainbow chunky pixels to make it more fun. With all the gaps between pixels, I created a simple interpolation algorithm that fills in samples between the pixels recorded.
To get the synth MIDI-controllable, I created a pitch shifting algorithm that skips recorded samples by some fraction (playing every other sample on the screen pitches the note up an octave). I then added multiple synthesizer MIDI inputs to get polyphony.
Sound is our ears picking up vibrations in air caused by an acoustic source. If we graph these vibrations we get a waveform, a visualization of the sound we hear. This synthesizer works by letting the musician draw any arbitrary waveform and hear it as sound.
