OK, so ... after a few days of listening with the 2050's I think I've got a bit more used to their sound.
There are some aspects that I like and some that I don't like.
The focus of my dislike with these headphones lies mainly in the soundstage presentation. Each time I used them I get the impressions I'm listening to closed headphones, not semi-open ones.
The sound is more panned out left-right, with a rather faint center stage. The don't seem to be able to project a continuous virtual plane, with a good focus in the center.
On the other hand they have good clarity and openness in the sound, which I expected to result in better imaging.
I'm also not impressed by the midrange of these headphones. The overall tonality is a bit to U shaped for my liking, and there's not enough weight in the lower midrange to really make it happen.
To give an example, on a music like Jordi Savall's "Les Grandes Eaux Musicales de Versailles", recorded in a very spacious and lively venue, the 2050's tended to sound a bit shouty an hollow.
Violins in particular had an artificial sheen and zinginess to them which I didn't like.
And the more I listened the more I started to dig out as much information as I could find about them and their close related cousins - the pro 80's.
First I'll start off with a waterfall plot of the pro80's. As the drivers and housings are virtually identical to the ones on 2050, there are some clues in there which may explain some of the shortcomings I'm hearing.
There are a couple of resonances centered around 10Khz (the dominant one) and around 6khz. This might explain some of the artificial sheen and fuzziness I hear in 2050's treble.
The pro80 plot also shows a lot of stray energy in the lower midrange and towards the bass. That's probably more specific to the pro80, being a closed design there is some extra acoustic reinforcing coming from the housing.
The 2050 sounds quite a bit more recessed in the lower midrange than I imagine the pro80's do, but I do think it shares some of the resonances in that region due to the similarity of the drivers and housing.
And then I came across this interesting mod of the Pro80:
Essentially he coated the inside of the cups with car undercoating spray, which functions as an acoustic dampener of the housing itself. That should reduce resonances inside the cups themselves by quite a bit.
After trying it myself on the 2050's I noticed immediate improvements in the lower midrange and mid-bass, which have been tilted a little bit. The tonality also shifted a little bit towards warmer.
The highs on the other hand have remained largely the same, probably a different approach is needed in that department.
It's possible some of the resonances come from the driver unit itself or the baffle it's mounted on.
I'll give the headphones a bit more time to settle in (or for me to get used to them more).
Probably I'll keep experimenting further with dampening different elements of the baffles, maybe different pads.
I'll keep you posted if I make any progress.