This was a really helpful article, thank you.
I actually got a pair of 569‘s myself recently because of it and am pleasantly surprised by its sonic performance.
It feels less muffled and more dynamic than I remember the DT 700‘s.
My only real complaint is the comfort due to the notch inside the ear cup. I think the pads of the HD 620‘s might help fix that.
Do you think you could measure a pair of 569‘s with HD 620 S pads? Sennheiser has them listed as compatible with the 569 and I‘d love to know how they would affect the sound.
I‘d appreciate that very much