Well that excitement was short-lived
The Sundara arrived, hooked it up and didn't like it at all. I was hoping for more clarity and transparency, but was getting less of it compared to my Fidelio X2s.
The way I would describe it, it's basically its sound signature with most notably elevated mids compared to the X2s that result, to my ears, in over-present mids that for me destroy the transparency, as they dominate the sound too much. Not sure if that makes sense. Guess I'm just an old fart too used to the X2s V-shaped sound
For many tracks that I listened, it makes that the balance of instruments and vocals is different, which in principle is fine and something you will get used to over time. However, in some cases/tracks I simply cannot hear the details that I'm used to hearing.
Take as an example a track like 'Little White Lie' by Sammy Hagar. It's a pretty decent recording IMO, but near the end of the song all instruments (drums, guitars, harmonica) go into this big-bang finale that on my X2s still stays balanced, layered and transparent, just to use my own layman wording. I can hear the separate instruments clearly. With the Sundaya, I cannot hear anything anymore other than a huge cacophony of noise because the mids are overpowering everything.
So basically I would be spending time trying to at least EQ the mids down I think, but not sure if that would fix all problems. With tracks that didn't have the overpowering mids issue, the Sundara wasn't revealing anything that I couldn't already hear with the X2s, and as said sometimes they would even be less resolving.
It was a fun experiment, but I'll be going on a listening visit to some shop most likely when I want to continue this quest, instead of ordering blindly. For now, I have concluded that I'm very happy with my current headphones
The Sundaya is already heading back to sender.