"Java Jive" wrote in message
...

The addition, subtraction, or other modification of harmonics is a
distortion.

True.

That's why the measure of distortion is called Total Harmonic Distortion.

THD is *a* measure of distortion, but it is far from being the only one.

It is well known why THD is a poor quantitative tool for evaluating sound
quality when there is enough THD to suggest audiblity. When there is so
little THD that inaudibility is assured, e.g. 0.01% THD, then THD can be a
useful tool.