More than that, the sound is defined by how the overtones change over time, and for acoustic instruments that's defined by various resonant modes and how they'r

More than that, the sound is defined by how the overtones change over time, and for acoustic instruments that's defined by various resonant modes and how they're excited. This article makes it sound as if timbre is static. It isn't. It's the changes that make instruments recognisable. A static slice of a violin timbre doesn't sound much like a violin. It's also wrong about having to use a 9ms slice. FFTs apply a windowing function which fades a slice to zero at the edges. Otherwise you get discontinuities which introduce spurious high frequency overtones which don't really exist. And so on. These are all things that some slightly deeper background reading would have revealed.