Some impressions would be great!
Yes, a comparison to the 400i and 560 would be great. The yolk on my 560 broke and I'm looking for an alternative planar - if the Sundara is as good as the 560 I'll eat my words and will buy another Hifiman product
Just warning the two of you that the last time I had the 400i or 400S was a while back. I heard the 560 for a brief demo only. The reviews for the three are here. FYI Guru has permission from HF to post links.
http://headphone.guru/hifiman-he-400i/
http://headphone.guru/hifiman-he-400s-review/
http://headphone.guru/hifiman-he560-planar-headphone/2/
The primary difference between the 400i (from memory) was that the 400i was not as universally adaptable in sound sig. It was finicky with source material and had a tendancy to sound bad if you didn't meet the requirements of source components or music type. I recall being wowed by the 400i with its breathtaking airy mids (that sometimes would get a bit hot) and also its inability to work well with modern pop/rap/rock and a mediocre to weak low-freq. The 560 was not a favorite of mine due to it being too bright and fatiguing for my ears. The 560 was indeed a audiophily superior (in the sense of how it seperates components and brings sound to the user) product with a fast and forward mid section. But I had problems with that as it was indeed TOO forward for me.
The Sundara feels more like a successor from the good ole HE5/HE6 days (which in my opinion had a much more do-it-all balanced sound sig compared to the 560). It comes at you with a incredibly balanced sound signature in how well it works with different music genres. I think the primary reason for this is its improved low-freq response (it now has a 'good' bass) and fine tuned mid section. An issue with using non-dynamic drivers such that we get to planars for headphones or Balanced Armature I've found in my experiene is that initial units/tunage using those technologies will produce highly seperated sounds that audiophiles look for, but lose out on the balance that dynamic drivers have brought to the game for generations. Dynamic drivers are always good for giving a very full experience with everything coming together, but lacking in its ability to seperate out components (in general, obviously the HD800 don't have issues with this).
The HE400i and 560 for me is almost this earlier tunage where we get some nice seperation of components and lots of people did like them as different audiophiles like different things. I'm a person that prefers a balanced sound that makes the music come alive, how well instruments or vocals are seperated/presented/coloring is second as a balanced sound is what is presented better in my opinion. The Sundara feels like a culmination of these past efforts. It now does the job of not only providing a top notch performance in seperating out individuals BUT ALSO, in its general sound signature just being insanely adaptible to anything you throw at it.
IT's also a fairly revealing can It has picked apart some 'lesser' studio masterings. Background noise floor and general audio engineering failures are more apparent with this can. On tracks I've listened to countless times on countless cans, and I would notice minor things in the mastering with the Sundara.
That's as much detail I have on it for now. Please hold for when the official review is posted on Guru. The above is just a quickly typed out impression of thoughts as they came to me at my keyboard. So you'll get lots of random ideas that lead somewhere and then trail off haha.
But I will say this just now. I am a huge fan of the Sundara. It has wowed the socks off of me for the price. And I've heard A LOT of headphones. Sure, disregarding price, there are better. But this is $499 for one compared to four digits.
My favorite thing about the Sundara would absolutely be its universally adaptive sound. It packs all the benefits a dynamic driver brings while also offering the insane sound pressure and fast attack that a planar can do.
Sennheiser had a new HD660S I gave a listen to for the same price. Yeah, Sundara's anyday.