if this were the case then Doppler shift would be a part of the natural
order of things musical, and Doppler shift could thus be entirely
disregarded as a source of "distortion", period!
I think this should pretty much drive the final nail in the Doppler
distortion issue's coffin, because if speakers introduce Doppler shift then
so does everything else which vibrates to produce sound. I still don't think
Doppler shift is introduced by speakers opperating under normal conditions,
but if it is, it's a part of the natural order and not distortion at all!:-)

The difference is that "doppler distortion" is a measurement that
compares an *ideal* waveform (ie, what's on the wire) with the
*realized* waveform (what's in the air). Distortion that isn't present
in the wire but is in the air is undesirable.

Yes, one part of the sound of a vibrating string is caused by a
"doppler effect" of the fact that the string is moving through the
air. (This may be inaudible, but that's besides the point).

However, that's part of the sound of the string, and therefore it's
desireable. If you were to then put it through a speaker that added
*additional* doppler (or whatever) distortion, then that would *not*
be desireable (if re-creating the recorded sound was your goal).

So no, this doesn't nail any coffins. Sorry.

It's like saying "electric guitar amps have harmonic distortion --
therefore it shouldn't matter if my studio's speakers also cause
harmonic distortion because this is part of the sound of the amp
anyway!" -- yeah, try to put that by any audio engineer

Ken