Contour

Contour is four instruments on a map and one finger moving between them. Each corner is a small model trained on one real instrument. It doesn't output sound, it outputs a description: loudness, harmonics, noise. A plain additive synth plays that. Between corners I blend the descriptions, so you hear one new tone, not two stacked.

I tried a plain crossfade first. In an early test a 50/50 mix of two instruments landed anywhere from 5% to 95% of the way across, because the stronger spectrum won.

Before training anything I ran four real notes through analysis and back out. Reed, brass and string came back close. The mallet didn't: its partials between the harmonics have nowhere to go but noise. That's roughly how Contour became a drone and pad instrument.

Current iPhones can't feel how hard you press, so Contour cheats. Press harder and your fingertip squashes flat, the touch gets wider, and that width is loudness. The one colour on screen is borrowed from the green glow of old VFD clock displays, a bit bluer and softer. I keep it for what's live: your finger, the pitch cursor, the readout.