well I'm sure if we go full Amir about it, we could very easily show situations where even 0.1%THD is noticeable. so I would be cautious about saying that we have a lot of transducers with distos below audibility.
on the other hand with most musics it can be pretty hard to notice stuff below 1%THD. after all, musical instruments generate their own fair share of harmonics, so it's not really surprising that HD from the headphone can end up masked.
so I'm saying no, and yes at the same time. I'm crazy I do what I want ^_^.