If you want to put it very directly, that was also crap.
Yep.
So it actually only makes sense to compare the speakers with each other.
As already said, if the original source is heard through a neutral speaker, the timbre comparison should be fair again - as long as the headphones are as neutral as possible, or even better tuned to the HRTF of the dummy head.
To make the comparison fair and meaningful,
@New Record Day should have provided the original source, folded with the HRTF of the KU 100.
Then it would really be possible to judge the sound deviations from the original source with any headphone, whether neutral or not, and at the same time have spatial information like a binaural recording allows.
In this way (and of course with adjusted sound pressure levels of the different speakers) such comparisons would really be a useful addition to measurements.
Unfortunately, I can no longer edit the error in my opening and the following posts