I would also submit that, even among a group of 20 year old audiophiles with hearing that would measure as "perfect" in a hearing test, there would be differences in the morphology of the inner and middle ears, as well as differences in the diameter and/or thickness of their tympanic membranes. There could be differences in the density, thickness, and length of the fine hairs that push out ear wax. Also, as mentioned above different people may have different neurological activity as the brain processes the sound.
It seems to me that all these factors could result in people with similar results on hearing tests actually perceiving the sound differently.
It seems to me that all these factors could result in people with similar results on hearing tests actually perceiving the sound differently.