Fairy Dust

There’s a video by Andrew Huang where he patches a Spectral Multiband Resonator to play six notes through a scale with delay and reverb. Every combination sounds different. He called it magic rainbow fairy dust. Someone turned it into a website years ago — click a button, get a random sparkle. Simple idea, infinite replay value.

Jason wanted a version with more control. So we built one.

The signal chain: sine oscillators through an ADSR envelope, into a 3-band EQ, through a dynamics compressor. Each note gets its own delay chain with a feedback loop, tone filter, and separate 3-band EQ for just the delay signal. A convolution reverb sits on top — with an option to reverse the impulse response so the reverb swells into the note instead of trailing after it.

The fun part was the randomizer. There are two modes: “smart” picks from scales that reliably sound nice (pentatonic, dorian, lydian), musical delay times synced to BPM, and moderate parameter ranges. “Wild” opens everything up — any scale, any tempo, any delay time. Most wild results are chaos. Some are genuinely beautiful. That’s the point.

The visualization maps to the sound. Twelve LEDs around the button correspond to chromatic pitches — the ones in the current scale glow dimly, the ones actually playing light up bright. Lines trace between notes as they cascade. The ring slowly rotates at a speed tied to BPM. When reverse echo is on, it spins backward. Small thing. Feels right.

Settings encode into the URL. Click share, get a link. Open it, same sound loads. No server, no database — the entire preset lives in a base64 blob in the query string. Old links gracefully handle missing or added parameters.

It’s live at magicrainbowfairydust.com. Single HTML page, vanilla JS, no dependencies. Hit play. 🪨