Not commenting on the Lyr + GS-X setup but just wanted to say that even in the same excellent source with the same amp, people would perceive sound differently. One undeniable fact is as we get older, our perception of the higher frequencies diminish. A setup that has a relatively harsh treble might bother the younger listening but not the older one simply because the older person cannot hear as high as the younger person for the harshness to bother him/her.
I did a frequency perception test with my dad (who's not that old, just in his 50s) a couple years ago, and while I could hear up to the 18kHz-19kHz range, his perception cuts off at around 10kHz-12kHz range. This is pure biology and there is nothing we can do about it (apart from cyborg ear implants I guess). So theoretically an audio setup could have a massive 10dB spike at the 15kHz area and he would be perfectly fine with it but I would flip the **** out.
With the HD800 here's one of my conjectures. Personal preference aside, perhaps in general younger people tend to prefer tube or warmer sounds, because the analytical sounds of certain amps can bother their ears with the high frequencies. It's like as we age, our ears' treble rolls off lol. Not sure though. I guess I'll test this out myself since I'm pretty young and just ordered a super neutral and transparent amp.
Now I know that audio recordings don't often go up to 10kHz+ frequency range, but still, the difference is there, and this difference has nothing to do with our personal preference of sound.