There’s a sound every pianist knows, and almost nobody can put in a mix: hold down the sustain pedal, lean into the strings, and sing. The whole instrument answers back, every string that shares a frequency with your voice starts to shimmer.
I wanted that as a reverb. Not an impulse response of it, but the actual mechanism.
So I built Sympiano: a free AU/VST3 plugin that physically models all 230 strings of a grand piano (or an upright) resonating in sympathy with whatever audio you feed it. Real string inharmonicity, felt dampers with half-pedalling, the overstrung bass crossing, a piezo pickup you can slide along the strings. Route MIDI at it and only the notes you hold resonate. No MIDI? Pick a key and scale, and the reverb stays in key with your track.
A few things I’m proud of:
- It’s the real mechanism. Digital waveguides for every string, coupled at the bridge — the shimmering “aftersound” of unison strings emerges from the physics instead of being faked with modulation.
- It’s light. All 230 strings run at about a tenth of one CPU core.
- It’s genuinely free. No account, no email wall, no dongle. Signed and notarized.
Listen to the demos and grab it at sympiano.com. If you make something with it, I’d love to hear it.
(If you’re curious about the music-theory side — the scale engine shares DNA with Harmonic Composer, my main project.)