Excellent article in Stereophile


This is one of the most interesting articles I've read on harmonic distortion and its affect on sound quality and why the classic THD is a worthless specification. 

https://www.stereophile.com/content/harmonic-convergence-effect-component-tweaking
128x128jaytor
This is actually an old article that was republished, but worth a read nonetheless.
It is worth reading for research sources, but I find the article itself riddled with opportunities for more questions, and honestly, self promoting.

I'm definitely going to have to go back to those footnotes though.