Scale Designer

Project intro

Scale Designer is a music-theory instrument that lives in a single HTML file: click notes on a color wheel to switch them on or off, pick a scale preset or build your own, then play it with your computer keyboard (A–L for the scale, Q–P for the octave above) or over Web MIDI, with a built-in synthesizer. It shows enharmonic equivalents (A Natural minor = D Dorian = E Phrygian = F Lydian), and number keys trigger triads or seventh chords from the scale. The maker is Dr. Ethan Hein, an NYU music-theory scholar who describes himself as "not much of a programmer". In his 2026-10-08 post "I vibe coded a music theory app" he wrote: "maybe this is my excuse to try vibe coding. So I told Claude to replicate the aQWERTYon. It made an HTML file that I uploaded to my web host, and there it was, a fully functioning knockoff of the app" — built, he says, in about half an hour with the free version of Claude. A music academic's half-hour instrument: the page is live and playable right now.