In the general case, what you do is you take a wideband excitation - like a buffer of random samples - and use it as the initial value for a system with a lumpy

In the general case, what you do is you take a wideband excitation - like a buffer of random samples - and use it as the initial value for a system with a lumpy frequency response. In this case the frequency response is very simple but more complex IIR filters work too. As the article says this is a good analogue for how a lot of musical instruments work. A string is a resonator, and plucking it gives it a wideband excitation.