Karplus-Strong synthesis is an approach to physical modeling that can be used to emulate string sounds. It’s based on feeding an impulse (often a burst of noise) into a delay line, and then feeding the output of the delay line back into itself.
This simulates plucking a string – the string will vibrate at specific frequencies and changing the length of the string changes that pitch. In Karplus-Strong synthesis, changing the length of the delay line has the same effect. And adding a filter on the delay lets you simulate dampening of the sound.
If you’ve experimented with Karplus-Strong synthesis, let us know what you’ve tried in the comments!