HiFiMAN HE-400

The title is not exaggerated either, but of course to get the HE-400s to that level you need at least a decent DAC and a tube or hybrid amp like the Schiit Lyr to even hear what they truly can do. Otherwise most amps will will work just fine with them! I have tried them with my Schiit Asgard solid state amp for weeks, but felt they need more that 1watt per channel (the Lyr has 6!). The gain in sound quality is extreme enough for most people probably, but as you get to really appreciate these cans, you will want to get everything out of them.

Simply put (without resorting to headphone comparisons which I did against the HE-400 which can be seen here: http://www.youtube.com/watch?v=9zdHTN5ysZQ ) the 400's have Superior soundstage, detail, and balance while still being exciting. There is only one other Planar headphone on the market now (Fostex t50rp and it's mods like the mad dog) but it doesn't touch the 400, HiFiman made the pinnacle of price/performance.

You may think $400 (or less used!) is a lot for a pair of headphones, but when you consider it's top of the line tech that headphones many times it's price use, you know you've got a smoking deal.
 
Note: My 400's have the MUCH better than stock velour pads and a Q-Audio braided cable.

Most people hate this headphone because of annoying treble spike and low mid treble but if just need to tweek EQ to see its potential.

Wow after not being active in head-fi for a couple of years and finally being back to be able to own a good headphone like the HE400 is such an honor.  I stop searching for awhile after owning the D2000 and now I wanted to find something to compliment the D2000, I decided to search.  I finally reached the HE400 and it reminded me what I love about this hobby and why I love headphones.  The HE400 is a headphone you can truly appreciate with smooth mids, nice black background, none offensive sound, open, comfortable, and look professional to boot!  I can't say more as everything can be found here in head-fi and to me word can't explain what these headphone can give.

EDIT:  My opinions and views on this set of cans has changed a fair bit after more extensive listening.  Please see the link below for my updated opinions on these headphones.
http://www.head-fi.org/t/755367/shootout-entry-to-mid-range-full-size-cans-feat-ath-m50-hd-558-and-he-400
 
My Story
First of all - WOW.  This is my first set of proper Hi-fi/Mid-fi cans.  It's also easily the best sounding anything I've ever had the pleasure of listening to.  However, since I'm new to the head-fi game, take this with a grain of salt. 
 
So where do I begin with these headphones?  I guess I should give some background on my listening history.  I wouldn't quite consider myself poor, but I'm definitely far from affluent.  This means that my listening experience has been severely limited.  Until I purchased the HE-400's, the nicest cans I've had the chance to listen to were a pair of my friend's ATH-M50's.  While quite nice, they didn't particularly blow me away.  The nicest pair of headphones I've personally owned were a pair of Sony MDR-MA 300's.  They're semi-open, have a LOT of fairly clean bass, recessed mids like you wouldn't believe, and decent highs considering the $50 MSRP.  I definitely got used to the very dark sound signature of those Sony's.
 
When I put the HE-400's on for the first time, I was immediately very concerned that I might have wasted $300 of my hard earned dollars.  They were a WORLD of difference from those Sony's, and I just didn't care for the sound signature out of the gate.  However, I decided to stick with them for a week or so and see if my opinion on the topic would change.  That was without a doubt one of the single greatest decisions I've ever made.
 
Although it took a while for it to sink in, I had a eureka moment a few nights ago as I was laying in bed, listening to a new album I'd been recommended (Dead Horse by Charts and Maps for anyone interested in a fantastic, FREE Jazz Fusion/Math Rock album).  While listening to the second track, I finally realized just what I'd been missing in all my music.  The mids were so clear and smooth.  The instrument separation was unparalleled to anything I'd ever heard.  The drums sounded realistic.  And then there was that saxophone.  It sounded like it was right in front of me.  I've never had such a positive visceral reaction to music before.  I found myself smiling uncontrollably (as an aside, I'm listening to the same album while writing this review and can't help myself from grinning like a madman).  I was hooked. 
 
I've listened to more music in the past few days than I have in quite a long time, and I'm finding it hard to stop.  If you're new to the world of headphones and any of this sounds like it might be up your alley, I highly recommend you just bite the bullet and cough up the $300 (while the sale lasts).  While I can't guarantee that you'll love them, the potential is definitely high with these cans.
 
Now, for the more technical stuff.
 
Build Quality
Overall, there's not a whole lot to complain about with the build quality.  The only real issue I've faced is this cable.  I hate it.  It's thick, it's stiff, and when I go to lay down in my bed, sometimes the audio will just cut out.  Others have pointed out this issue, and I've never had this problem with other phones, so I know the cable is to blame.  I'm also not a huge fan of the connectors, but at least I can live with those.  I'm definitely going to replace the cable soon.  If anyone has recommendations on an inexpensive set of aftermarket cables (preferably under 100 USD), please, PLEASE shoot me a PM. 
 
It should also be noted that these are HEAVY CANS.  They weigh in at nearly 1 lb.  The flip side to this is that they also feel quite sturdy. 
 
Headband could also use a bit more padding, but that's part of the next segment.
 
Comfort
Overall, they're pretty good.  I would prefer some extra padding on the headband (which I'll definitely be adding to these).  I don't have any problems with the stock cushions, other than a TINY bit of sweating, but I may try out the velour pads just for the hell of it. 
 
Drivability
I read one review where someone said his amp (I believe it was a Schiit Magni?) was having trouble driving these headphones.  My experience is the exact opposite.  I can drive these perfectly well from my ipod nano, and my stock gain (2.5x / 6x) O2/ODAC combo can absolutely CRANK these things.  On low gain I never have to turn the knob past maybe 20% of it's travel.  I shudder to think of the damage I could do to my hearing with these cans cranked on the high gain mode.  Since these cans have an impedance of ~50 ohms, pretty much any source with under 5 ohms of output impedance should have no issues with damping. 
 
Sound Quality
I've pretty much covered it all in my story above, but I'll reiterate here in case some of you skipped it.
- MIND MELTING MIDS
- Clear, present bass with a bit of a punch.  Wouldn't call this a bass-heavy can by any means, but it's certainly not lacking in quantity or quality. (EDIT:  After further listening on some of my favorite albums (that I feel also happen to be poorly mastered (see most The Fall of Troy albums) I've found that the HE-400's bass response just isn't up to par in terms of presence.  My previous pair of cans did just fine with TFOT, and you could actually hear Tim's bass through the mix, but with the HE-400's I have to use a fair bit of EQ to get it to shine through at HALF the volume of my old pair.  Bit more presence would be appreciated, but the clarity is definitely a stellar upgrade.)
- Fantastic treble.  While others have most definitely complained about treble issues with these cans, I can't say that I've experienced the same.  Your mileage may vary, but that's my two cents.
- The best clarity and instrument separation of anything I've ever had the chance to listen to (bear in mind that I am EXTREMELY new to this, so my experience is very limited.)
 

Conclusion
For my first entry into the world of Hi-Fi, I think I've made an excellent choice.  Although I didn't care for them out of the gate, I think these cans may very well be the best investment I've ever made (aside from my gaming rig.  It's pretty much my child.)  I may just save myself the time, money and trouble and just call this my end game, but at the same time it's making me wonder what lies just beyond the horizon.  Wish me luck on this crazy adventure that we call audiophilia, and don't forget to enjoy the music!

This is my first puchase of "audiophile level" headphones. I was looking for cans which can play "every genre" included traditional musics (gamelan from Bali & Java).
Purchasing done mainly based on internet review. It's a rather risky desicion for $400 for me
 
But, it's really whorted the price. I've burn the cans about 40 hours now, and they're getting smoother and more transparent. Especially for the highs. I use Marantz PM5004 amp and mostly FLAC file. They sound soo beautiful.
 
Jazz, rock, classic, acoustic, gamelan, bamboo music just so alive. I only miss a little from female voices. And suprisingly, even my rockboxed sansa clip plus can drive this cans beautifully . Great.
 
Overall, this's excellent price/performance cans. And sound very fun. I need a shorter cable too

After using IEMs almost exclusively, I decided that it was about time to step into the realm of full-sized cans. I wasn't about to spend $1000, but I still wanted better than mid-fi sound. My options were pretty limited, and it came down to either the HD600 or the HE-400. In the end I decided that, despite the HD600's more refined sound, that the HE-400 had what I was looking for (tight, linear bass, excellent detail, and a 3D image). So I pulled the plug on the HE-400 (and a pair of velour pads), and never looked back. 

My first impression was a good one, and they sounded exactly as I expected them to based on measurements and first-hand accounts.

Bass

I'm not at all a bass-head. I find bass to be the must unimportant and non-essential part of the frequency spectrum because it provides little musical information and serves little purpose other than adding body to the music. That said, the quality of the bass is very important to me. I cannot stand liquid, texture-less bass, and I'm not a fan of elevated mid-bass either. Thankfully, the bass on the HE-400 is as far from that as possible. The response is almost perfectly linear, it's extraordinarily tight, articulate, and well-textured. It hits hard, goes low, and does everything that bass is supposed to do without ever getting in the way or disappearing. It's as close to perfect as I can imagine a headphone being in that regard.

Mids

Mids are very important to me. Nothing will ever sound right if there's trouble in the mids, and they're absolutely essential to the reproduction of the human voice. The mid-range presentation on the HE-400 is interesting. The lower mids are very full and somewhat forward, whereas the upper mids are more recessed. They're certainly colored, but it's not a coloration I'd call "offensive." The mids here are very rich and organic without ever sounding thick or syrupy. I think that's partially due to the elevated treble and excellent extension that gives vocals great air and a "breathy" sound. On some recordings the mids can sound a bit distant, but that's not an issue that I've run into very often.

Treble

The treble is the trouble spot with these cans. The treble isn't poor by any means, but it is significantly elevated in the highest octave (10kHz+). The treble can be very hot on some recordings. Some people may like the extra air that comes with this kind of treble presentation, but it's a bit much for me. I find that it obscures detail a bit, and can dominate the signature at times. However, the treble responds very well to EQ and sounds excellent with just a few dB decrease. Extension is great and the the headphones definitely do not want for air. 

Soundstage/Imaging

I've never heard a headphone at this price that presents the audio image anywhere near as well as the HE-400s do. The soundstage is open with great height and depth with excellent layering, and width that is neither unrealistically large, nor cramped. Imaging is excellent, making it easy to pin-point audio cues and effectively sorting the various layers of the soundstage. 

Signature

The HE-400 signature is interesting. It doesn't really emphasize any region, but it somehow manages to be both dark and bright. It's not prefectly neutral, but it's not highly colored. It's just neutral enough and just "fun" enough to appeal to a wide range of tastes. It also responds very well to EQ (particularly in the bass, likely due to the very low distortion and linearity), though I'd avoid messing with the mids too much, as there is a bit of distortion there that can be exacerbated with EQ. However, you can tame the treble and crank up the bass as much as you want with little to no ill effect.

Design/Comfort

I've never had any comfort issues with them, and though the design seems a bit "cheap," I've not had any issues there either. They are a bit heavy, though, so keep that in mind. The stock cable isn't the greatest; it's thick, heavy, and a bit stiff. Don't be too rough with it, because there are reports of it shorting, or the sheath splitting. 

Overall

I've not heard a better headphone in the $300-$400 range (including the HD600). It does just about everything right, and very little wrong (and what little it does wrong is easily fixed). For the HD600 owners out there, they make a perfect compliment to the HE-400. I've not come across a better value in the entire world of audio. 

First off my gear is HeadRoom Micro DAC and Amp.(I don't see how people get by without the crossfeed circuit on older rock recordings) Out of the rather cheap box the high-end was brittle and harsh and the bass boomed. The midrange was just OK. I have a Ayre Acoustics system burn-in disc and after 100 hours of brown, pink, and white noise along with Zappa's G-Spot Tornado from The Yellow Shark these headphones transformed into something wonderful. The highs were tight and accurate, the bass had a lot of power, but was also accurate, and midrange vocals were something to behold. I've always been a Sennheiser/AKG man and had never listened to planars before. For $299 (plus $10 for the velour pads) I don't know if their sound is for everyone, but do yourself a favor and audition these headphones before you make your final decision. I don't think these headphones are going to be powered by iPods or most MP3 players. They are not that efficient and I don't know where the iPod friendly deal started, but if HiFiMAN did they are going to disappoint a lot of people. These are NOT appropriate for mobile use. They leak sound back in the room more than most open backed 'phones do and a dedicated headphone amp with decent gain is required to drive them. I wonder how well the Audioquest Dragonfly would drive them. I'll bet not too well. They may be efficient for planars, but they're still planars. My last pair was AKG K702s and the AKG's were quite a bit louder. I'm curious how the HE-400i's will compare. For 500 bucks they better be an improvement. I spent $150(ProCable Panorama) as I found the stock cable lacking. I know that's a lot of money for $299 headphones, but it was worth it. Plus this cable is well built and should,last for years so when I upgrade I already got the right cable. If I get an amp with 1/4in. jacks, I'll have to send it back to cablePro for a new plug.
 
I know there are better sounding amps out there than the HeadRoom Micro, but none that have a crossfeed circuit. Maybe HeadRoom will start building amps again someday. I just sent it in to replace all the 3.5mm jacks. Getting it back today! Been using the headphone jack on a pair of powered computer speakers with the volume 3/4 of the way up and with the bars on the graphic eq on Foobar maxed out to get more gain. There's just no way any player is gonna be hot enough for these..

Upon getting them the first thing I noticed was the build quality, its very good as you'd expect from HiFiMan and also how comfortable they are. I had other cheaper headphones but they weren't this comfortable, I can wear these for hours no problem at all.
 
As for the SQ its just great and I'm quite hard to please when it comes to SQ.  Three things I look for in a good IEM is detail, good mids and a good soundstage so I was hoping the HE-400 could stack up. Now with the soundstage I knew they would be good being open-backed and man are they, very wide with excellent depth and good height along with great imaging and good separation. Now the mids are the meat of music so they have to be good and the HE-400 while not as forward as I like they sound great, smooth and warm with good detail just how I like it. As for detail that was my biggest worry because coming from BA based IEM's like the SM3, e-Q5 and BA200 they all have very good detail and micro detail. The HE-400 really surprised me with the level of detail, now they don't quite have the micro detail of most good BA IEM's but they're not to far behind, I don't feel like I'm missing anything in the music. The bass and highs are also very good with the highs being a bit bright but not to bad over all and the bass on planars I've heard is very good and the HE-400 is no different with nice punch and very good depth and rumble but these aren't true basshead headphones though.
 
So over all I'm very happy with the HE-400 and honestly I haven't really been using my IEM's since I got these a little over a week ago. They have good detail and a great presentation so if your looking to get into good headphones unlike Beats or even Bose the HE-400 is a great place to start and I'm already looking into getting the HiFiMan HE-500 because planar magnetic is the way to go imo.

These are amazing, especially when paired with the EF-5 amplifier. Would recommend to people looking at headphones under $500. The quality and soundstage is unbeatable, works wonderfully with all types of music.

I initially had my eyes set on the HE-500s but after some research I decided that the sound signature of the HE-400s may suit my tastes better as I predominantly listen to EDM (Tech House, Minimal, Trance, GOA, Psy). Initial impressions out of the box were quite impressive. For those of you who have yet to try a Planar Magnetic headphone - the detail and clarity are something else compared to dynamic headphones. There is no background distortion or noise at any volume as the background remains completely black.
 
The soundstage is adequately wide and does a great job at projecting space between instruments and vocalists, so much so in fact that I often forget I'm wearing headphones in a small, cramped room. 
It's the micro-details however that really allow me become totally immersed in my music. I'd best descibe the soundscape as being in a moderately large auditorium with perfect accoustics while vocalists and primary instruments are right there beside you - maintaining the intimacy. Live, lossless recordings are a wonder to behold (Coldplay - Live 2003 anyone?)
 
The bass is extremely accurate and the impact is surprisingly good for a completely open headphone. I do love the fact that the bass doesn't intrude unless called upon by the track. It allows me to enjoy my tech house/minimal tracks for their deep, thumping basslines and at the same time it can take a back seat when listening to accoustic or chillout/lounge music. This is unlike most "basshead" headphones where bass is pronounced everywhere, whether it is required or not.
I would love to try these out with a tube-amp as sometimes I do feel like the M-Stage may be too neutral for my tastes for some of my darker recordings and there could be a little more sub-bass impact; however as my equipment is limited I am unable to judge if this is down to my source/amp or the headphones.
 
Despite my affinity towards a U-shaped sound signature, the mids are probably the highlight for me and perhaps even converted me. I have never heard vocals produced with such clarity, emotion and musicality and wouldn't have thought it achievable at this price range. Everything from Barry White to Vocal Trance is outstanding. I wouldn't say the mids are pronounced though, they are neutral if anything allowing for very accurate and believable reproductions of the human voice.
Listening to Nora Jones (Come Away With Me) is almost a haunting experience as it genuinely feels like she is singing right beside me. Her voice is portrayed with quite an ethereal tonality and there is no unnatural resonance whatsoever on her extended notes.
Mind you this is all coming from someone who doesn't really listen to jazz/accoustic so let the impressions these headphones have left with me be an indication of how impressed I am by the HE-400s.
 
Now I read numerous times that the highs aren't quite neutral with the HE-400s as with their older brothers but I can honestly describe them as fast, extremely well detailed yet rolled off just enough to take the edge of some hot recordings. I think HiFiMAN have done a great job with providing the detail and presence in the highs while somehow avoiding them from becoming fatiguing.
 
Comfort wise, the earpads are height adjustable and they do swivel, so it should fit most headshapes. I will point out that the head-clamp is stronger than usual but I'm sure that will subside after I have worn them for a while. I have had no issues with wearing the HE-400 for extended periods whatsoever but I can imagine them being a little less comforable for someone who is sensitive to head clamp. They don't sit on your head quite as softly as the Audio Technica's winged design but they are snug do a better job of staying on your ears.
 
 
 
Overall, I'd recommend the HE-400s for just about any genre as I couldn't really fault them at anything in particular. Orthodynamics are quite revealing by design so you will need to provide them with a proper source file, I've been pretty disappointed with any files <192kbps but that's a given on a quality headphone such as this.

This is my second mid to high end headphone. And it so far has really wowed me. Im just gonna start with the bass, its amazing. Its very deep and detailed with good impact and texture and its fast, im a bit of a basshead and these will bring the thunder without interfering with anything else. They dig just as deep as my dt770s with almost as much impact and they dont muddle up the mids. The highs have tonnes of detail and are sparkly, but i dont find them fatiguing at all. Mids sound very good on them as well, i really enjoy female vocals on them. Most of the music i listen to is electronic where bass and speed really matter, im running them through my schiit modi and magni, this is a very good combo. The magni gives these lots of juice which planars love. A lot of people say that the leather earpads need to be replaced with the velours. So when i purchased them i got the velours as well, and i found that the velours made the highs way to splashy and the bass slightly anemic. I also find the leathers are quite comfortable after being worn a while. Ive worn them for over 6 hours and havent had any discomfort. They are a bit heavy but i got used to it. Overall this is a wonderful headphone, and its bass can satisfy a basshead without a problem

I still recall the day I placed my order for the He-400's, I waited with anticipation and days seemed to last an eternity. But the moment they arrived and I connected the dac to my computer, I was severely disappointed. Needless to say I listened to them for about 30 minutes before I put them back in the box and left them there. My father is also pretty passionate about audio and knew beforehand that I had ordered these headphones. When he asked about them I just told him I'm returning them, he was curious as to why so I hooked them up for him. He listened to them and looked at me and said why don't you like these?
 
They sound extremely clear and detailed. I explained to him that I was expecting them to sound incredible. That same day I processed my return but the company I bought them for offers a 60 day money back guarantee. So I decided I would give them another try and eventually the sound grew on me, and I began to appreciate the clarity and the separation of the instruments. The amount of detail I noticed subtle things in my music that I had never heard before and I had never experience sound stage this good.
 
However for the many great things that the He-400's do right they also have their flaws. My biggest gripes with these headphones for me personally were the build quality and the comfort. These headphones were probably the most uncomfortable pair of headphones I have ever owned. They are heavy and produce a lot of clamping pressure. In all honesty I could not use these headphones for more than 30 minutes before I started to feel strong discomfort. The other fault lies in build quality, in my opinion these headphones don’t look or feel like $400 dollar headphones.

The review is based on the stock pads, not based on the upgraded velour pads.
The only problem with the sound quality is a weird color in the upper mids, around vocal range.  This is due to the stock pads that come with the headphones and must be replaced or modded.
They sound fantastic other than that but they just are not comfortable if you're not used to planars.
I expect these will grow on me, especially when I get the pads replaced.
 
Update:
Since modding and swapping pads on these headphones I must say it unlocked the true potential for these headphones.  Jergpad mod or velour pads will significantly improve their sound.

The HE400 from Hifiman is a great value. For someone looking to a.) try a planar magnetic headphone or b.) find a pair of cans that will offer excellent, natural sound at a solid price, then this is one you need to consider. 
 
They're built like tanks! Although the amount of visible plastic is scary at first, its very obvious once you pick them up that they're going to take a few knocks before you have to worry. From the headband (very comfortable) to the metal gimbals to the shielded cable to the plush earpads, the HE400 won't make you feel timid in handling them. Also, since it comes up all the time, I've had no problems with the cable connectors. I can't say why or why not, but they don't seem problematic to me. 
 
It also bears mentioning that the housings are very large. Like huge. Largest I've seen. But they don't touch the ear at all, obviously an intentional design to create a room for the ear (or because of the massive planar magnets required). 
 
Now for the sound.
 
First word that comes to mind: natural. Nothing sounds "enhanced" to these ears.
 
Bass
The bass is solid and reaches quite low without making me feel like I've got a subwoofer on my head. One of the best ratios of quality to quantity I've heard.
Mids
The mids are very clear and neither forward nor recessed. Upper mids are a touch more present than their lower counterparts, but neither sounds unnatural. I can hear all vocals, guitars, and midrange instruments very clearly. 
Treble
The treble is nicely extended but never fatiguing or harsh. I've read a few reviews claiming the 400s were too bright and I'm very glad to say that I disagree. I could see that they wouldn't play too nice with low quality source material, but as they are, the treble is once again, very natural and clear.
 
Soundstage
The depth of stage definitely bests the width although both are still very good. I assume that the room in which my ears are sitting is a direct contributor to this. Once again a very natural sound, no depth so great that I'm left feeling that I'm 30 rows back, but also not so forward that I feel like I'm squished between the bass and drums.
 
Separation
The separation is good, not great. My Grados best it, but that's not to say that its non-existent. Its just not studio recording quality.
 
All in all, I'm glad I've gotten my hands on a pair of HE400s. Although they're a little on the heavy side, they are still rather comfortable and have a great sound. Very organic and natural. They certainly sound best after amplification, but they don't beg for it. Just remember if you're looking at planars, some meaty amplification is gonna get the best out of them for you. 

Before I own this HiFiMAN HE-400, I owned a pair of Alessandro MS2i Headphones (Dynamic driver, Open) and I thought this was the best headphones. I was wrong until I try this HiFiMAN HE-400 (Orthodynamic aka Planar Magnetic Headphone, Full size). This is an amazing headphones with panorama soundstage, amazing mids, excellent bass, crisp at high, lovely treble is there and this headphones is so comfy. Some people commented it is heavy, quite true, when I first wore it and I felt the weight but after I wear it for couple of times....It just so comfy and comfy is the word that appears in my mind. I listened to this headphones before I went to sleep and it is dark in my bedroom and I closed my eyes.....the panorama soundstage is so big for live music....it just so wide and lovely. I don't really have many negative review for this pair of headphones. I simply just can't find it now. After 50 hrs of break-in I started to get goosebumps and the instructions recommend 150 hours of break-in. I can't wait to reach that hours and see what I feel at that time. If you love musical instrument music, this is definitely the one I will recommend to you. Whenever I bought a new pair of headphones or earphones, I always tested them with my Audiophile Reference IV album. The things that annoyed me is the cable is too long...10ft, it just too long for me. The headband is just too thin. I am looking for addition headband to wrap around it.

Not perfect but they do a lot of things very well, probably the best value headphones. Bass and midrange are excellent, treble is too bright and harsh but with EQ it sounds ok.

***Update 1/9/2014
 
I've written a longer review elsewhere in the forum.
 
In short, these phones' offer tremendous sound for the money. Well-textured, virtually transparent, fast attack, with a balance tending toward "bright". They will present your most complex recordings with an effortlessness you've likely not heard before. The bass is incredible - in the sense that it can be punchy, and very well extended. You will notice bass lines differently with these, and sub-bass frequencies skipped by most headphones will be replicated here with little distortion. If you happen to listen to everything (like me), you know how important it is to have a balanced sound, and these have it. These phones are also known to respond very well to EQing. I do EQ treble downward about 2-3 dB as it can be a bit overemphasized with some genres. I also like to add about 2-3 dB in the 50hz area to add some weight to the bottom end. It is great to feel like I have such control over the 'final sound'. But sadly, some of this is a result of the unforgiving nature of the HE-400s - they will not 'fix' poorly mastered recordings or force their sound onto them. In a sense, they are only as good as your recordings are.
 
But these have convinced me that planar technology is the real deal, I doubt this sound can really be emulated by traditional driver technologies anywhere near this price. Overall sound will scale with a good amp / DAC (~half watt or so), though they will get adequately loud with most common 1V sources like laptops and phones. These cans can be a bit "fatiguing", but much of the fatigue has been corrected with minor EQ tweaks and modding the stock pleather pads / using the velours. Coming from German phones, I actually would rather have a more aggressive sound and experience some fatigue than suffer a 'laid back' sound when I am in the mood to head bang.
 
Would have given them 5 stars except for a few things. For one, I think the stock cord is a bit thick and stiff, and also way longer than necessary. After about a year of ownership, there is some fraying in the stock cables where they connect to the cups. I worry about long-term survival of the threaded connectors on each cup, but they are holding strong. In this price range, a nice metal headband and cup holders are welcome, but some slight "creaks" from the plastic are not. Other users have disconnected cups from the headband, as apparently, they are only glued on. Earpads easy to remove, and the tabs are not breaking, which has been a blessing as I have swapped the pads on and off many times at this point.
 
Comfort could be better - the clamping force is a bit intense at first, I needed to bend the headband slightly. I quickly swapped the thinner leather pads for the slightly thicker velour from their more expensive models. Leather or velour, the pads are quite stiff though not uncomfortable. I have since 'modded' the pleather pads by removing the foam spacer rings and cutting holes into the backside of them to improve damping. It improves on the feel of the pleather and the sound and is worth doing, but I still like the 'breathability' of the velours more, and they are still an upgrade in that sense (plus they sound better than stock pleather). The cups adjust and swivel, but are stiff and should be adjusted with care (pinch the headband and logo as you do it). Headband padding is too thin and I experience pain once in a while. It also gives me 'headband hair'. These phones are only 6 oz heavier than my lighter sennheisers (HD595), but they "look" and feel a lot bulkier. The threaded cord/cup connection grazes my shoulders when I turn my head which I can't imagine is great for the phones or myself.
 
But I can listen to these for hours anyway, the great sound just makes up for a lot of shortcomings. They are excellent headphones overall, but objectively, the comfort is simply no comparison to Sennheiser, which is often forget-they're-on-my-head good. The slightly aggressive sound may not be for everyone, and many are 'underwhelmed' by the sound at first (they seemed quite lean to my ears initially). But the HE-400 satisfies me much more than any phones I've owned before. That said, I knock a star off design for weaknesses in cable attachment / bulkiness and materials (stiff foam, possible cheap plastic), and 1.5 stars off for a sound which is fatiguing, a headband that can seem harsh, and cups which are hard to seat comfortably on my head (compared to other phones from which I have not experienced these issues). But if sound quality were the main criteria, good luck finding a better pair of phones for $400. The HE-400s are the real deal.

When I originally got into this hobby some 2 years ago, my first run of purchases included Sennheiser HD650's, Denon D5000 and Ultrasone Pro900's. I also had a couple beaters from Koss laying around like the Porta Pros (which I LIKE!). So upon purchasing my first true head amp (a Fiio E10) I thought my journey was over.... I had an amazing closed headphone, an amazing open headphone, a decent amp/dac... nuff said. Lets close the book on this consumer business and listen to some music.
 
From there I focused a good amount of my energy on (A) fixing up my 54 Lincoln and (B) mechanical watches..... I was in the throws of said watch obsession waiting for Steinhart to fill inventory on the Ocean 44 dive watch when I saw an episode of "How It's Made" on TV at the AKG factory in Austria where they take you through the steps of construction on one of the K702's.
 
Headphones!.... OH I LIKE THOSE
 
Since Steinhart was pushing their restock date back to August... maybe I can spend some of that money that is burning a hole in my pocket on a pair of Headphones.
 
And so the bug bit again.... But this time reading through forums, websites and reviews the kiss of death was bestowed on the K701 and 702 (which were my knee jerk target purchase after watching the show) but words like: lacking bass, thin sounding, airy and very NEUTRAL were intertwined into descriptions of their sound.... meh! I cannot handle thin sounding anything.
I've been to too many live shows to be able to pass off a thin sound as accurate.
 
Also (to me) the word "Neutral" conjures up images of a lifeless two dimensional sound that is lacking pace rhythm& and attack. Neutral is about as exciting as FLAT
I cannot imagine an OEM that would enjoy reading a review of their products, headphones, speakers or otherwise as "very flat and neutral".
 
So after jettisoning the 702 notion on its face, further Headfi forum reading of 'this vs that' impressions and product reviews and general chatter brought forth numerous mentions of a new player in the game... A company out of China called Hifiman who's entire line up of headphones consisted of planar magnetic drivers and open back designs. Even though the company hails from the PRC, they have a presence on US Soil that is comprised of a technical support staff and New York based distribution.The more I read about the Hifiman planar magnetic headphones, the more they starting working their way to the top of my list.
 
My pops raised me on a steady diet of vinyl with big power wars era receivers and massive floorstanding dynamic speakers but I remember spending time at my Uncle Johns in the summer where he had 2 big Magneplanar speakers set up in his game room. I don't remember a whole heck of a lot from back then but I do remember that I wanted my Uncles system.... So it became clearer and clearer to me that Hifiman was going to benefit from my next purchase. About the time I started my hunt, the HE400 model had been on the streets long enough to get through Rev 1.... and long enough for a couple of reviews to make it onto the street.
 
An article from Headfonia gave it a restrained thumbs up but Steve Guttenberg of CNet Audiophilliac fame gave it a gushing review. So as an impressionable young mark (er man) these last two votes of confidence were enough for me to pull the trigger. And so about 10 days after purchasing the headphones from Amazon for $399, they arrived at my doorstep. However upon taking delivery of the box there were obvious signs of having shipped direct from China and markings on the box gave me the impression they were shipped from a Chinese retail outlet as an in store demo. When I opened the box I was even more dismayed. There was no fancy case like had been shown in the literature and early reviews... Just a simple retail class cardboard box. I opened the box to find a pair of what looked to be a pair of blue HE400 but they were covered with a white dust and seemed to have been haphazardly packaged into the box.
 
"Is this some damn knock off or something?" was my original thought... 
 
The sticker on the exterior of the box seemed to imply that this was some demo model... yet I paid full price.... What!
 
Needless to say the Hifiman HE400 and I did not have a very good introduction... no love at first sight here.... I was on high alert once I saw that the package had made its way from China and because the way it was boxed with the headphone crookedly placed in the box, it did not seem to be packaged with the type of professional polish one would expect to find from a relatively high cost consumer product targeted for retail sales. I was therefore a bit miffed from the start. Then I plugged them in and pushed play and that is where all the hand wringing fell away.
 
Up until this point all of my headphones were on the warm and/or bass heavy side.... Denon D5K's, Ultrasone Pro900's, Porta Pro's and Klipsch Image Ones that I once heard described on Headfi as "bass fart cannons".... so my predisposition of what a good headphone sounded like was a bit tilted to the basshead side.... With all the hype I expected something similar but different (you dig?) But plugging in the HE400's I was taken back initially.... They were clear, very clear and very crisp.... the bass was there but certainly not up with the D5ks or Pro900s... Its not a basshead can. But as I listened and listened I had that "AHA!" moment.... These things sound good... very good!
 
The HE400 sound is not lush or warm or thick like many dynamic offerings.... It is smooth but hangs its hat more on clarity and providing a balanced presentation of the music. Some have called it a bass heavy can but I don't see or hear that at all. Comparing it to the Pro900 and the Denon D5K its sound is much lighter and fast.... If the sound of the Pro900 is overly thick and bassy.... audio maple syrup.... then the HE400 is distilled water... faster, refreshing, clearer but it doesn't lack for musicality.... What one does discover listening to this planar magnetic headphone is that despite having a super clean and clear treble, the slightly more forward and engaging mid range gives it a very "LIVE" presentation. It does not have that heavy full bodied pulsating rhythmic drive of similarly priced dynamic cohorts, but that livewire midrange provides this growling power to guitar driven rock that makes you want to listen to music. That is good enough for me!
 
Shortly after this I purchased the planar magnetic darling of Headfi, the Audeze LCD2. I was originally assuming that the HIFIMan can would lose its luster after the LCD2 arrived but this was not so.... Mind you the LCD2 has a lovely way about it... a beautifully resolving sound and penchant for low volume listening... the ease/ effortlessness with which the LCD2 can play the most complex and formidable low frequency passages is amazing.... I give credit to its lightning fast planar membrane.... It sounds wonderful with jazz, oldies, and classic rock.... but what I discovered after weeks and weeks of comparing the runt of the Hifiman planar line with the Audeze cohort more than twice its price is that with more up tempo guitar driven music the HE400 actually provides just a bit more impact to bass (especially with less than reference sources) and there is this "LIVE" factor to the mid range that gives it a more realistic sound with guitars.
 
Now I am splitting hairs here to draw differences but I saw the LCD2 as sounding more like listening to music at home while the HE400 was more like being at a show. Saying that is a very stern criticism of the LCD2... I am trying to paint a very thin line (a very small deficiency) with broad strokes but I heard it so what am I to do. That ever so slightly tipped up mid range response on the HE400 makes it just a bit more involving and immersive. The LCD2 holds you back ever so slightly from the music and thus can cause disengagement with mid range focused guitar rock.... Considering the better part of my library is punk, rock, and alternative... the HE400 is actually the better all rounder of the two.... What is more is that while the LCD2 can give you ridiculously well resolved low frequencies, I mean it mines the depths of a song to absolutely subterranean levels with perfect texture and resolution, the HE400 actually provides a bit more punch and impact to its low end despite being a bit less confident in its resolve. The HE400 is prone to get a little tizzy on some heavy low end stuff where the LCD2 holds crystal clear.... but the HE400 makes up for its slightly messy presentation with more punch and dynamic weight.... you can hear it with the Audeze but you can feel it with the Hifiman. This desire to meet you halfway is what makes the HE400 so special.... It is not as euphonic and lush as the HD650... but it does sound similar in a lot of ways, in that its presentation is on the polite side of things compared to very forward and bass heavy cans like the Denons and Ultrasones. However in terms of accuracy vs. impact it has found an amazingly intoxicating balance that stays fun while never getting fatiguing. The LCD2 offers you resolution and clarity in spades.... Its technical speed is unmatched by the HE400 (which is how it ought to be) but the LCD does take maybe a few step further away from the stage and this slight recess strips away enough of the emotive experience that the HE400 has a justified place in my collection.
 
It is certainly not the last word in headphones but considering its price and the competition in the $400 +/- market it is an amazing performer. In the right setting with enough current feeding its drivers, it is an outstanding all rounder.
 
HAND WRINGING
 
I have one maybe two gripes with this headphone and they have ZERO to do with its sound quality. One is the weird reverse polarity coaxial connectors used to connect the cables to the cans.... The connectors are actually a pro television and radio fitting for antenna connections so it is an odd choice.... and very difficult to source. More importantly is that twisting the cable over and over to connect and release the cables is bound to eventually cause a short or some other form of damage in the cable.... My particular model came with a 6 foot Canare quad OFC cable and after connecting and disconnecting a few dozen times the collar on the cable side of the connector actually pushed through the back of the stem and fell off.... rendering the cable dead.... Hifiman was quick to send out a new replacement cable to me (Hat tip to Vince at Head Direct!) but if there was one thing I would change it would be that. Another line of defense that I may likely pursue is Toxic Cables adapters. If you buy a cable from him with say mini XLR terminations for Audeze cans he can build a set of adapters for Hifiman connectors so you can bypass the twist connector all together. You'd have a couple of odd little earrings dangling off the bottom of them when not connected to the cable but... This should only bother the most retentive of people in the hobby. The other mild nuisance is that the logo and markings are all painted on the headphones..... Thus after a few short months of handling them, the L & R designating which side is which have all but rubbed off.... The headphones appear to be perfectly symmetrical in build so I don't know that it changes anything to wear them either way but I opted to tag the stems with red and black sharpie to keep track. However it'd be nice if they could find a more permanent solution for marking the sides.... and the brand.... I've got to believe that eventually the "Hifiman HE-400" marking on the blocks will go to the wayside as well. Beyond these minor grievances I am superbly happy with this headphone.... It is a worthy adversary in the $400 realm and beats the snot out of its similarly price AKG, Beats and Grado adversaries... The HE400 is an opportunity to get some of the planar magnetic sound for significantly cheaper spend than normal. It is worth every penny. You will not regret it.

There really arent much to say.
Everything is good with these headphones except the treble spike.

I'll start by saying that I have not owned a great deal of various pricey headphones. These are my best cans so far, but I've listened to a couple other comparable headphones that I'll mention later. Also, I'm not aiming to write a comprehensive review - some others already did a much better job at that than I will ever be able to. What I aim to do is point out the only fatal flaw I've found in these headphones that I didn't see anyone else mention, along with some other impressions.
 
My background: I listen to a whole lot different styles of music (from folk to IDM to ambient to jazz to blues to rock to pop to rap, just to give an idea). Over the years I've realized that the best sound is monitor sound. The playback device should introduce as little distortion as possible. The first really good headphones I've heard were my friend's Shure SRH-840. Then I bought myself German Maestro GMP 8.35D - awesome headphones widely regarded as fit for studio work. And then I've gotten HE-400.
My system is a Windows 8 laptop -> EMU 0404 USB -> headphones. Additionally, I own the O2 headphone amp and I have tried taking the sound from EMU's linear output and putting it through the O2 instead of using the EMU's built-in headphone amp. Unsurprisingly, I could hear no difference whatsoever. Because, well, 0404 is a solid device. EMU has less power, but it wouldn't mean I would be less deaf if I listened at peak volume - both amps are perfectly capable of producing over-the-top sound pressure levels with HE-400.
 
Build quality: I have no complaints. One thing I've noticed is a tiny bit of play in the ear pads where they are attached to the driver housings. It's not an issue at all, but something I would reasonably expect $400 phones to be free of.
People complain about the cable connectors, but I've detached and re-attached the cable a couple times and had no problems doing so. The connectors are clearly not convenient, but not in any way problematic. And because they're screwed in you don't have to worry about sudden connection loss.
The painted white logos wear out extremely fast. So would the L/R marks, but those are cleverly placed where you hardly ever touch them so it should be fine.
 
Comfort: I generally don't have problems with headphones at all, but HE-400 are clearly a bit more comfortable than GMP 8.35D thanks to less clamp force. They're heavier, though. I can feel them on my head, but I've never been uncomfortable yet. The only minor complaint (and I have the same problem with many other phones) is the headband cannot be adjusted to be short enough to fit my head well. It's just a tad too long in its most retracted position, so the earpads touch the upper part of my ear due to the headphones sitting too low. I'm an average height and build person with an average head, so not sure what's wrong there. Perhaps, my ears sit higher on the head than usual? Anyway, GMPs and HD580s have the same problem. I need to almost place the headband on my forehead to compensate for the extra length.
 
Sound: I won't specify a list of recordings used as some other reviewers do, simply because I've had the phones for years and listened to a whole lot of music from my collection of 29K tracks.
Just one example would be the album "Roadhouses and Automobile" by Chris Jones which is widely regarded as having great recording quality.
 
At first HE-400 seemed slightly superior in every aspect compared to GMP 8.35D (which, I'll remind you, are very solid phones and that's not just mine opinion). The main difference was slightly wider soundstage, and generally the sound was different in a way I couldn't pinpoint. Then I've listened to Sennheiser HD580 and realized this must be what open headphones sound compared to closed ones. I clearly hear this difference (that I still cannot exactly describe nor do I understand why it even occurs). I cannot claim I hear any specific planar / orthodynamic / isodynamic sound, though - all I hear is decent open headphones.
Bass is just the right amount and very deep. I was afraid these open ortho headphones would not match closed GMPs, but they do!
These phones are slightly more detailed than GMPs as well HD580s, and they seem to have quite flat frequency response across the whole range.
But here's the catch, and I only noticed it recently: I was listening to Rob Halford singing "You've Got Another Thing Coming" on the 2005 Japan remastering of the Screaming For Vengeance album, and I've noticed unpleasantly harsh sound. Then I've found some other tracks that displayed the same problem. Long story short, there's a peak somewhere close to 1KHz. I don't have the equipment to pinpoint it, but adjusting the 1KHz slider of a 20-band digital equalizer by approx. -4 dB solves the problem. I would rather use a parametric equalizer, but again - don't have the equipment to find out the right frequency, Q factor and attenuation.
 
Summary: solid headphones, very versatile, almost monitor sound quality with the right amount of everything except for a narrow frequency response peak at ~1 KHz that will make some tracks sound very harsh and loud (some vocals, harp, trumpet can strike this spot).