I have tried these out now after letting them run for a few hours, and wanted to share my impressions.
Background: I wanted to list what headphones I have experience with, because I think that's always helpful for someone to see if they agree generally with someone's taste and impressions. One of the nice things about living in NYC is there's a great headphone store where, pre-COVID at least, you could actually try a lot of exotic headphones (Audio46).
In terms of reference quality headphones, started with the Sennheiser HD800. Great headphones, and I think it's always a good reference point since they are so established. But then I fell for the Focal sound, and got a Stellia and Utopia. (I was traveling a lot pre-COVID so need closed back headphones that were easy to drive, hence the Stellia.) I was very happy with those for awhile and played with different cables because the Utopias could be a little too bright for me sometimes. I settled on Danacable's Lazuli Nirvana, which I enjoyed very much (and use for the Susvara as well). In terms of amps, I used the Chord DAVE's native headphone amp at first, then Focal Arche. I was chatting with Vinh Vu who sells Danacable stuff (great guy), and he lent me this prototype amp they were working on. It really brought something and I bought it - I think they sell it now as the Danacable Headspace Amp.
I hadn't tried Hifiman before. I think it was lot of the negative crap on the forums and reddit. I've learned now that a lot of people on audio forums just like to throw hate around, and many opinions are thrown by people who don't have actually have the headphone. And the Susvara just seemed unreasonably expensive compared to the Utopia. But I was chatting with Vinh and he mentioned the Utopia was great, but the Susvara was even better. In fact, that's what Dana at Danacable uses and the Headspace Amp was built in part to drive that to its max potential. His comparison was the Utopia was like Sugar Ray Leonard, fast and quick, but the Susvara was like Muhammad Ali, great all-around with no weaknesses. So I tried the Susvara, and it was pretty much perfection for me with the amp combo. It had everything that I wanted and it was also really comfortable to boot. Then I bought other Hifiman headphones like the Ananda BT for bluetooth, and I liked the sound a lot better than the Sennheiser Momentum I was using. I also have a Sundara for low level use (like office calls into my mic). So I like the Hifiman sound a ton, please keep that bias in mind.
I have not tried any electrostatics before except the Koss. I did try the Abyss AB-1266 when deciding on the Susvara, and it is a terrific headphone, but I preferred the Susvara.
Shangri-La vs. Sennheiser HE-1: Anyone who is considering getting the Shangri-La Sr. is considering the HE-1, of course. This is a really tough one because it's not like you can really compare the two side by side in ideal conditions unless you're really lucky. I've been burned many times where I hear headphones/speakers in the audio store and it sounds great, but doesn't sound quite the same in my own home set-up, for better or worse. I did hear the HE-1 once, but it wasn't in ideal conditions and there was a fixed playlist (I couldn't hear the music I'm familiar with most) so I'm not going even try to compare the two. In the end, I went with my gut because I really loved the Susvara sound, and figured if Fang liked the Shangri-La even better then I should try it. I also didn't want to pay for the marble finish and the DAC for the HE-1, I very much like the DAVE DAC and wanted to use it. I'm sure the HE-1 is a terrific system.
Shangri-La vs. Susvara: OK, I stand corrected. The Shangri-La is better than the Susvara, even after just a few hours of break-in.
It's really quite a magnificent sound. As good as the Susvara is, the Shangri-La tops the sound on every measure: detail, resolution, imagine, sound stage, low fatigue. I can tell because I end up listening to whole albums when I wanted to just one song. It is very revealing, I wouldn't say harsh, but definitely you will have a new appreciation for music production.
Soundstage is more global than the Susvara.
You know, one purchase that I made that I'm still not sure is worth it is the Chord M Scaler. I'm still not sure, but I can say that finally I do hear something consistent in terms of the different upsampling modes with the Shangri-La.
Here are some of my references for picking out resolution.
Smashing Pumpkins '1979': there's that iconic part of the sound where Corgan is going "oooo....ah..." and it's compressed really fast with a ton of reverb, so it sounds like a guitar or something. Never heard his voice in that part so clearly.
Guns' N' Roses' Sweet Child of Mine: Whoever mixed this did a very mediocre job compared to other tracks on the album. I play guitar and have been trying to hear Izzy's rhythm guitar part (on the left side of the soundstage) in isolation, but it's mixed poorly and is very muted compared to Duff's bass and Slash's lead. I can hear the separation clearly with the Shangri-La Sr.
Led Zeppelin, Stairway to Heaven: Ok, most of us have heard this song to death. But Plant's vocals are hard to clear with certain words, especially in the beginning where he's almost whispering. I can now more clearly his humming over JPJ's recorder in the first part. But also when he says quietly in the first two minutes "she can get what she came for", the "came for" is really hard to make out but here it's very clear.
But putting aside the detail, there is that magic quality for me that we all are chasing, I think. You know what makes you immersed in the music. With these headphones, it kind of sneaks up on you; if you're multi-tasking you may not notice it. But if you close your eyes on these and just listen to the music, it's pretty amazing and you will be transported.
It's more comfortable too, and the Susvara is already quite comfortable. I think people underestimate comfort with headphones, it makes a big difference in terms of how much you will actually use them; nothing breaks immersion like actually feeling the weight or clamping pressure on your head.
I haven't retired my Susvara, I have it set up at a different place. So over the next few weeks if I have anything more to add on this I will.
Is it worth buying? Impossible to answer, since it depends on your disposable income and how much you like audio. I wouldn't take a loan out for it, like I might for a house. I also think it's a bit wasted if you don't actually do much listening to music by itself (i.e., as opposed to having music playing in the background while you do something else). I mean you'll still get a difference but it really shines when you just let yourself get absorbed in the music with your eyes closed. It has a high ceiling. But if you are making a luxury purchase, like the sound of other Hifiman headphones and spend a lot of time listening to music, I think it's well worth considering.
Please note I did buy the whole package, so I am using their amp. I don't know how much of the sound is the amp, for all I know a different, cheaper amp might sound even better. I also don't know if the other electrostatics like Voce, Stax are better, just don't have enough experience with them. At least the amp can play two electrostatic headphones at the same time if you ever wanted to run a comparison.
Hope this helps anyone considering it. Pic attached, it's not a good one. But you can see the amp doesn't look as heavy it is.