I’m replying to my own first comment, in view of some of the recent discussion here. The HE-560s and the old STAX are still very close. With the Mjolnir modified STAX SRM-T1S, I do think that the STAX headphones beat out the HE-560s overall. The electrostatics are just lighter and very fast and detailed. But the HE-560s are a very close second.
They are slightly more convenient. I can drive them with the iFi xDSD, which I did not have when I first made the comparison. I usually drive them with my Headroom Standard (2016), often using the Dragonfly Black as input to the Headroom, even though it is able to drive them - although not well.
I look forward to some time in the future when I have a more potent DAC/AMP combination, as it is clear that just like my old Rectilinear III Speakers, they like to have the authority of more power behind them than is needed to merely drive them.
When I analyze this thought, it sounds like hokum, but it is not. My guess is that having additional power - even if not actively used - adds a degree of control. I’d love to hear some of the more technical folks describe this feeling. With regard to my speakers, I heard that authority over the years with Dynaco Mark IIIs, with Tigersaurus (125 watt RMS mono amps), and with my present Wyred4Sound 1000 watt class D. I heard it slightly less with the 100 watt RMS Sansui AU-919, but it was still there.
I did not hear it with a 70 watt RMS Onkyo integrated, that was otherwise quite good, and they were always wanting when I had to drive them with 40 watt Lafayette equipment. Just seemed like there was clarity in bass drums and percussion in general.
So I get the identical feelings with the HE-560s as I go up in power, if not in volume. Perhaps it is the planar magnetic design.
My Sennheisers - next in quality - both the HD-580s and 6xx are close - but not quite in the same league.
I hope this is helpful as a longer term listen to @pukkita. With adequate power, they seem more natural. I find them very good on acoustic jazz combos, classical guitar, and chamber. They are also very revealing in live rock recordings, but can be merciless on acoustically bad venues.
It’s hard sometimes, to properly compare studio rock albums among a group of really good quality headphones as production values and choices have so much weight.