^ Nice notes - thanks for the detailed comparison
The AT headphones I've tried do have a bright sound to them. When I used to ran the W1000X through the hrt microstreamer, I felt it was very bright. Through the meier stack, it sounded a lot more refined. My ears probably got used to the signature, and now I find them pretty smooth and mellow. Still brighter than the T1 though. So I understand where you're coming from.
Also I listen to headphones, particularly the the AT woodies at lowish volume (at around 8-9:30 on the volume wheel). They get loud quick, and when too loud I find the sounds sometimes can be slightly messy. YMMV of course.
On certain genres when they hit their sweet spot and are truly wonderful. I've still found enjoyment listening to all kinds of music with the W1000X.