Ah, you're not the only one. A lot of people feel that HD600/650 are a reference for midrange but I think it's just wayyyyy too forward and together with the narrow soundstage it's so fatiguing to me. I was never able to listen to my HD650's for longer than an hour without getting absolutely tired of it. The way Beyer does midrange on the Dt880 for instance to me is much more balanced and closer to a neutral sound. But I had been used to Sennheisers for so long that when I heard the DT880 for the first time, I just couldn't believe how airy and spacious the sound was, it was an entirely new thing for me. I knew then that my music needed to have those qualities to some extent going forward.
I guess we all hear differently, to end with a platitude
Yeah I don't feel the HD 600/650 are the ideal midrange reference either. They are way too forward, especially in the upper mids (when I do FR sweeps they are notably too loud here compared to the rest of the frequencies) and they don't do it in a way I find engaging which hurts them even more for me. I just think Beyer does midrange better in general, they don't have the hard sounding mids the HD 600 and HD 650 tend to have. I don't think I've heard hard fatiguing mids on any Beyer I've owned even the incredibly midrange forward DT 480.
I thought the HD 560 S had a more narrow soundstage than the HD 650 and even the narrow sounding HD 600. I did not like the HD 560 S; found it lacked body, detail, irritating upper mids, it was, boring, etc. I found the HD 600/650 a bit too forward in the midrange as well, I always thought Beyer did midrange better. Senns some reason often have this annoying grittiness and hardness to their upper mids and treble that really fatigued me overtime. There are other headphones with forward mids that I prefer to the Senns, so I basically given up on them.Same here. Amiron Home, Amiron Wireless, T5p.2 and Tygr 300R. I had the DT880 and 770 but had to sell them because no space.
So it was not me thinking the HD560S has a narrow soundstage. I had the same issues and then at some point I really got tired of it and got rid of it.