Karplus-Strong string synthesis

Karplus-Strong string synthesis is a method of physical modeling that loops a short waveform through a filtered delay line to simulate the sound of a hammered or plucked string or some types of percussion. Although it is useful to view this as a subtractive synthesis technique based on a feedback loop similar to that of a comb filter for z-transform analysis, it is better viewed as the simplest of a class of wavetable-modification algorithms now known as digital waveguide synthesis, as the delay line acts to store one period of the signal.

Alexander Strong invented the algorithm, and Kevin Karplus did the first analysis of how it worked. Together they developed software and hardware implementations of the algorithm, including a custom VLSI chip. They named the algorithm "Digitar" synthesis, as an abbreviation for "digital guitar".