Physical modelling synthesis uses an excitation signal driving a resonant body model

Physical modelling synthesis simulates acoustic instruments by separating the sound generation into two stages: an excitation signal (bow, pluck, breath) and a resonant body (string, tube, cavity). The exciter provides the energy input; the resonator filters and shapes it into the characteristic timbre. This maps naturally to SuperCollider patches: an impulse or noise burst drives a series of comb filters, delay lines, or waveguide feedback loops to model string resonance. The Karplus-Strong algorithm — a recirculating delay line with a low-pass filter — is the canonical minimal string model. More sophisticated models add damping, stiffness, and nonlinearity.

Examples

// Karplus-Strong string
SynthDef(\ks, { arg freq=440;
  var exc = Impulse.ar(0);
  var dly = CombL.ar(exc, 1/20, 1/freq, 10);
  Out.ar(0, dly * 0.3)
}).add;

Assessment

Build a physical model of a plucked string using CombL. Vary the frequency parameter and compare the decay time with a real guitar recording. Modify the LPF inside the loop to simulate different string materials.