This is not really a review. It is more of a praise of the LCD-X if you like rock/metal and have the funds to get it.

Some facts about me and my relationship to headphones:

- I used to own the Hifiman Sundara, Audeze LCD-2.2, Sennheiser HD660S, Audioquest Nighthawk and Nightowl. And a lot of portable ones. These are my reference headphones when comparing to Audeze LCD-X.

- I am in no way an audiophile. I cannot tell frequencies apart. But I can tell if the bass is too boomy or the high mids/lower treble is too hot (for my preference). I know what I like.

- I mainly listen to post-rock/metal, rock, sing/song-writer, some jazz fusion.

- I pair the LCD-X with a Fiio M11 and custom balanced 4.4 cable. I have listened to this setup for more than 6 months.

So, I have been in the game for 4 years now. Quite early on, I purchased the Audeze LCD-2.2 and paired it with Chord Mojo. Back then, I did not appreciate it enough and sold it for the Hifiman Sundara. I really liked the Sundara but found it too bright for the genres I was listening to. Then I got the HD660S. I liked it more than all my previous headphones I owned (I forgot how the LCD-2.2 sounded). I was quite satisfied with my HD660S until I again had the opportunity to try the LCD-2C at a local Hifi-store. I was euphoric. Then the guy working at the store suggested the LCD-X... Wow! I was blown away from the first song. Could not stop listening. I had to get it.

The build quality is second to none. Sexy steam punk... in black. Either you love it, or hate it. I love it. It is heavy, but comfortable. I can wear it for 3 hours without any fatigue. But it is not an "all day long" kind of comfort. Hence "comfort" stated in both the pro and con section.

I find the sound to be flatish with a hint of warmth. There is a dip in the high mid/low treble region. They are quite airy but non-fatiguing.

- Bass is fast, reaches low and hits "audiophile hard". Perfect for fast drums and realistic bass guitars.

- Mids are clear and somewhat forward (more thick than not). Electric guitars sound absolutely perfect. They have lots of air around them and have a great bite.

- Highs are spot on for me. Not harsh, not bright. But also not recessed or rolled of. Semi forgiving I would say. A poorly recorded track will still show its nasty faults. However it is still enjoyable.

- Soundstage is perfect for rock. Not wide but HUGE. Its hard to describe. I find it to be more deep than wide. Well mixed rock tracks sound epic.
I can understand if classical music is not the best on these though.

These are my impressions. If you like rock/metal, these are the end game. I have at least not heard better for these genres. Try them out and you will be smitten. Rock on!

edit: artists that sound fantastic on the LCD-X: Tool, Neurosis, Cult of luna, Mogwai, Explosions in the sky, Sigur Ros, Noorvik, Mono, Leech, Khuda, Isis, Ef, Esbjörns trio, Gaspacho, Grails, Norah Jones, Pink Floyd, Led Zeppelin, Tonbruket...and so on.

edit 2: I now got the Ifi idsd micro black label to pair with the LCD-X. Wow.
I have read many reviews about "off timbre" and so on. Yeah, The 1-2K region is recessed, compared to the Harman curve. I couldn't care less. I can enjoy everything on these headphones. I dont want to spend this kind of money on a headphone and only listen to 5-6 classical records. The LCD-X will show you the recordings faults, however they will never give you headeache. 6 stars out of 5.

First off- I pair the Sundara with the mighty Chord Mojo. I find the sound signature to be balanced with no signs of sibilance or fatiguing highs. The lows are punchy and fast. The mids are very neutral to my ears. Vocals are neither forward nor recessed. Highs are perfect for my taste. Usually I prefer darker headphones, but the Sundara made me change my mind. It is nor veiled nor harsh. Again, balanced in every way.

To my ears, the Sundara is a chameleon. Sometimes it manages to sound warm and sometimes cold. I guess that is what you call a neutral headphone (well, close enough at least). You hear what was intended by the artist.

I listen to a variety of genres. From post-metal to jazz. I think the Sundara handles it all with ease. OK, sometimes I would prefer the body of something like the LCD-2, but to me, the Sundara is a better option. It is way more comfortable, has better sound stage and is way easier to drive. And it is half the LCD-2s asking price. I have tested and owned a lot of headphones, including the LCD-2, but the Sundara is the only one where I simply cannot find any deal breakers.

If you prefer classical, modern or rap, audition the Sundara. If you listen to guitarbased genres - folk, rock, jazz etc. the Sundara is a no-brainer. For the asking price it simply is a beast. Highly recommended.