So.. I've just tried the Sundaras!
I'm not completely mindblown, but they gave me a Very Positive impression.
It's also the first time I listen to planar-magnetics, and the difference is very apparent.
-In comparison with the DT880 Pro, Sundara is considerably more Detailed..
The response is very Fast and Accurate, and that coupled with the natural Frequency Response,
and the Clear/Crisp sound, really mark a difference.
All this Clearness let you appreciate the instrument's Timbres in great Detail,
and the definition/accuracy and separation of instruments is improved.
The Frequency Response is very Natural, and quite similar to the Beyer.
It's got a Very Similar overall tonality, very Open and Airy..
Maybe it's got a hair more presence in the early-Highs,
and that makes some instruments like Flutes stand-out a little bit more..
But it's not any more Bright overall than the Beyers,
in fact I would say their top-Highs are a bit more correct and well bounded.
So in essence this is very positive, cause they bring all this extra Detail and Clearness,
but preserving the overall Tonality and FR.. IOW, not at the expense of being any more Brighter than the Beyers.
The Comfort is better in the Sundaras, good fit.
The pads are Deep enough so your ears won't touch the drivers, and they are Soft to the touch yet Firm as they retain their form.
The Design is excellent, and the Build Quality is good.
Maybe not as indestructible as the Beyer, but very close alltogheter.
-There's only two things that the Beyers seem to do better, or at least differently.
First I guess is the natural difference between the Dynamic and the Planar Magnetic techs..
since the Beyers are Dynamic they have more Resonance, in a let's say Euphonic and Liquid way.
In a way it's more Dirty,
as if the different sounds/instruments and frequencies bleeded/interfered or blended with each other.
But on the other hand it's also a Natural and desirable effect,
as this lets the Resonance of the instruments come through, making the notes Bloom..
And I would say it's also and "artistical" effect, making the sounds blend mre. as when a painter mixes the colors in a palette.
The Sundaras are so Fast and Detailed, they don't let this Bloom or extra Resonance appear, they are Dryer in this aspect;
but on the other hand they are much more Accurate and give a Clearer representation of the sound/instruments/timbre..
Secondly the Sundaras have less Bass and Sub-Bass.
It's all there, they have proper Extension, but the Lows are Recessed, just not as Present or loud as in my Beyers
(which I had on the side for A/B-ing..)
It's not a radical difference,
and I know this particular unit of Beyers I've got have a relatively generous Bass response..
But it's enough to make a difference, and alas, that takes two points out from the Sundaras.
-All this withstanding, there's however an important detail I must add..
This particular unit of Sundaras was
New, and had less than 2 hours of play!
(I had the shop call me whenever they got them for exposition..)
It seems Hifiman recommends a 150h burn-in period,
so I guess the overall character/response of the headphone is likely to Improve.
And hopefully this could mean improved Bass response,
or perhaps more Resonance, who knows..
-So in essence, and considering the absolute technical differences..
Sundara seems to be a nice Magneto-Planar alternative to the good old DT880.
The overall Tonality, Airy/Open Character and Sound Signature is very very similar,
the difference relies in the different technologies used..
Sundara is naturally Faster, much more Accurate and Detailed.
DT880 is more Euphonic and Resonant, an perhaps a tad more Liquid..
(yet not nearly as Liquid as the Meze Classic for instance)
And that's very good!
-So.. since I could not try the AKG, and the Senheiser sucked..
I guess this narrows down my actual options:
1. Fix my DT880's - Play the Beyerdynamic Roulette/Raffle and buy a set of replacement drivers for 100€.
If I'm lucky and the drivers turn out to be good, I could have a nice proper balanced unit.
However the Doom factor here is considerable..
2. Get the Sundaras - They could be a nice complement to my DT's,
offering more Detail and Accuracy, which I guess can only be good for mixing..
And they could hopefully improve after the burn-in period,
giving better bass and resonance, and after I got used to them, could potentially end replacing the DT's completely..
3. Scrap everything and go for the DT1990's.
For this I would need to listen them first, which I think is gonna be difficult in Barcelona..
But there's still the Potential to find the end-it-all headphone that will take me out of this misery.. lol
Ofc that means I would need to spend 500€ more in the Beyer Roulette,
with the potential risk of failing pray to it, having to fight the Shop to replace the headphones numerous times..
Or not even getting a proper unit at all, which then would have to be sent to Beyer's repairmen,
who will not acknowledge their fault, and I will have to keep them with the message "it enters inside our parameters".. lovely!
(and this is exactly what happened to me on my third and last DT880 Beyer experience..)
-Other than that..
I don't think there's many more contenders that I could consider here.
But well, one thing is clear for now:
the Sundaras are very Good!
PS:
The music was played through a Astell&Kern KANN portable player,
which is the same player I demoed the Senheiser HD600 with..
I'm not an expert in portable players, but seeing the price tag I guess it was good enough for the task,
and seemed to properly drive my DT880.. so I guess the Sundaras were well feed too.