mmmt-tools / Synthesis / karplus–strong
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Karplus–Strong · plucked string

The simplest physical model, and a beautiful one. Fill a short delay line — exactly one wavelength long — with a burst of noise, then feed it back on itself through a gentle low-pass. The noise circulates at the pitch the delay length sets, and each trip round the loop loses a little high end — so it starts bright and clangy like a real pluck, then mellows and decays into a clean string tone. No oscillator anywhere. The loop is hand-written in an AudioWorklet (a delay-node feedback loop can't reach these pitches).

0
waveform
spectrum

String

3.0 s
0.50
0.90

Release

0.25 s

Hold a key to let the string ring on its own; releasing damps it over the mute time, like resting a finger on the string.

play with your keyboard (a s d f …) or click the keys · retrigger a held key to re-pluck