I really expected to like this as it seemed to be an audiophile favorite here. I listened to it for a few days to ensure that burn-in could occur, whether it be my brain of the headphones themselves.

The problem with this headphone is that it's super harsh, harsher than the DT990. And interestingly it sounds dark.

I don't know how they pulled that one off. At least the bass is fantastic, typical of orthos, but at this point, that bass extension and slam is pretty much useless due to that massive treble spike I'm hearing around the 10K+ region.

Review: HiFiMan HE-400 (revision 4)
 
published on October 14, 2013
 

(click for larger pic)
 
- download a printable 4-page PDF version of this review (target goes to a location on my Dropbox)

Intro

I originally got interested in the HiFiMan HE-400 due to early positive impressions by other Head-Fiers and eventually bought my own pair in November 2012, new from HeadAmp. This review contains my thoughts on the headphones, which I owned up until August 2013. Caveat: for various reasons I didn't listen to these headphones that much while I owned them and used them only for about 65-80 hours. I don't personally believe that planar magnetic headphones burn in either, which is another reason that the headphones never got many hours on them.

Equipment Setup

- Source components: Plinius CD-101 (CD player) (Signal Cable Silver Reference power cord, directly into wall), desktop PC w/ headphone jack on Yamaha YSTMS50 speakers
- Analog interconnects: Emotiva X-Series RCA
- Headphone amplifiers: Burson Soloist, HeadAmp GS-X MK2, Schiit Magni
- Headphones: Audio-Technica ATH-AD2000, MrSpeakers Mad Dog 3.2, Fostex TH900
 
The HE-400 (revision 4) was used only with the velour earpads, not the stock pleather ones.

Evaluation Music

- Alison Krauss & Union Station - Paper Airplane
- Andrea Parker - Kiss My Arp
- Goldfrapp - Black Cherry
- Helloween - 7 Sinners
- Infected Mushroom - Vicious Delicious
- Julia Fischer - Bach Concertos
- Machine Head - Through The Ashes of Empires
- Massive Attack - Mezzanine
- Megadeth - Countdown To Extinction [MFSL]
- Orbital - Snivilisation
- Ruth Moody - The Garden
- The Crystal Method - Vegas [2007 Deluxe Edition], Tweekend
- The Prodigy - The Fat of the Land
- Trifonic - Emergence
 
Negative Aspects
 
The flaws listed below collectively soured my experience with the headphones:
 
- Comfort & fit: The HE-400 was very uncomfortable on my head mostly because of the headband, which wasn't padded at all and frequently left the top of my head sore. I also never got a full "seal" with the ear cups due to the size and shape of the frame—i.e., the headphones were just slightly too big for my head at the smallest slide setting and didn't "clamp" enough to my head either, leaving slight open space. That may in part explain some of why I heard what I did with the HE-400, and it's admittedly possible that my fit issues could very well have been the source of my negative experience with the headphones.
 
- Cable quality & appearance mis-marketing: The HE-400's cable was one of the worst things about it to me. For one, the screw-in connectors were an annoyance to deal with (primarily because they were too small to easily turn) and always left me wary that they might break as well. In fact, I did break one of them from over-torquing and had to get a replacement cable through HeadAmp. Second, I thought the 3.5mm mini plug at the other end was a major error too for two reasons: (1) 3.5mm mini plugs usually indicate that a headphone can be driven well by portable & computer sources. I found this to not be the case at all with the HE-400. On my computer it required extra-high volume to sound loud. And on my amps it required high gain (where configurable) + high volume adjustment to sound loud. (2) I occasionally experienced sound drop-outs when I used the cable with a 3.5mm-1/4" adapter and frequently had to "shake" the adapter's connection to the headphone amp in order to regain sound. This occurred with all 3 amps, so it wasn't limited to a single amp. The problem was clearly with the cable's 3.5mm mini plug, as I've never experienced the issue with any other 3.5mm-terminated headphones.
 
- Overall lack of mid-range: I put the HE-400 through every major music genre that I listen to (classical, bluegrass/folk, metal, electronica/trip-hop) and had a hard time appreciating it for most of them simply because I found the mid-range overall to be too recessed, which negatively affected my enjoyment. It was just way too thin-sounding and never presented instruments like bass guitars or other elements like male & female vocals as properly full-bodied. It severely detracted from atmospherics/ambience as well—on music that was atmospherically dark, like trip-hop and certain types of metal, the stylistic "darkness" that should've been there was missing with the HE-400. I don't mean sonic darkness, I mean that kind of heavy, creepy, menacing quality that some tracks can have (for example, Massive Attack's "Inertia Creeps"). And the HE-400 tended to shove key musical layers to the background, like drums/percussion. In that aspect it was like the sonic inverse of the Audio-Technica AD2000/AD2000X, which both bring percussion to the extreme foreground.
 
- Boring bass: You'd think just having a lot of bass on a headphone would make it fun-sounding, right? Wrong. It depends on how it sounds, and the HE-400 had one of the most boring bass responses that I've ever heard. It reminded me of the "oonce oonce" bass in dance clubs—completely generic and indistinct with absolutely no real energy to speak of. Ok, the HE-400 had a lot of bass quantity. But the quality of that bass was just non-exciting, as it was just the equivalent of a generic-sounding bass "drop". There was just no impact, or force, or anything that sounded like the bass had some type of forward motion and wanted to keep pace with the rest of the music. And there was no tightness to it either, it was just a generic-sounding plodgy and ploppy blob. In fact, if there's one word that could sum up the bass for me, it'd be "ploppy".
 
- Spiked & unrefined treble: Ok, a lot of headphones have unpleasantly spiked treble. The HE-400 was just another case of that to me, and I like treble too! I'm a fan of the treble in the Sony Qualia 010 and Sennheiser HD800 for example. But the HE-400 had just too much zing and sibilance that made my ears wince on too many occasions. And it was unable to stay clean at high volumes, on music that was especially treble-heavy—i.e., it tended to blur ambient electronica at points where the music got increasingly complex & trebly.
 
- Over-diffusion: I'm generally not a fan of headphones that diffuse/separate the sound a lot, especially when it's obviously unnatural to the recording. (Case in point: HD800.) The HE-400 overdid this as well IMO and completely lost a sense of cohesion—it split apart bands way too much so they didn't sound like they were playing in the same room, for example. I'm pretty sure that most metal bands don't intend for their music to sound overly diffuse/separated and this aspect of the HE-400 especially annoyed me when listening to metal.
 
Positives?
 
Normally I'd try to balance a negative review with some positive aspects but unfortunately my experience with the HE-400 really turned me off to it, way more than any other headphones in recent memory. So I apologize if I can't come up with anything especially positive to say about it. I guess the best thing that I can say about the HE-400 is that it was technically competent—i.e., it had treble and bass, a fast impulse response, etc, but for me it strayed so far from the point of conveying music that it ended up registering as below-average in my personal rankings. Additionally, by the time I really started putting the HE-400 through its paces for this review, I also had the MrSpeakers Mad Dog 3.2, which I'd be inclined to say is the superior-sounding planar magnetic headphone for less money.
 
As far as amping went, I used mostly the Burson Soloist and HeadAmp GS-X MK2, and only minorly the Schiit Magni. The Magni was able to drive the HE-400 effectively but that's about all it did—the HE-400 really didn't sound that great on it, especially compared to the Burson Soloist. The Magni was also unable to drive the HE-400 at ultra-loud, non-earsafe volumes without causing audible distortion in the bass frequencies (on extra-low/powerful bass notes). And although the Soloist and GS-X MK2 were better-sounding amps, neither of them helped to rectify my issues with the HE-400. The GS-X MK2 in particular only amplified its sonic flaws.
 
Addendum - Review Notes
 
My review notes are included here in their own section for convenience. These provide specific detailed info not included in the review. Notes start below the asterisks.
 
***
Terrible cable quality at both ends (screw connectors too small to easily handle, connectivity issue when mini-plug used with 1/4" adapter). 3.5mm plug mis-leading, HE-400 nowhere remotely efficient enough for use with portable sources. (Needs High gain to achieve sufficient volume on Soloist and GS-X at moderate settings.)
 
Overall passive, laid-back sound, in a V-type signature, with very emphasized treble and bass.
 
Julia Fischer - Bach Concertos

1. Strings clear & "shimmering", not too unlike HD800, but also diverges instrument sections widely. Very separated sound, not very cohesive. Almost too much channel separation. Treble overall reminiscent of HD800—has similar issue as HD800, causing wispy/glossy-sounding violins. Lacks subtle musical details that the OII would have (inflection, dynamics, bowing technique, etc). Lack of overall mid-range content negatively affects both violins & harpsichord.

 
Massive Attack - Mezzanine - "Teardrop", "Inertia Creeps"

1. HE-400 fails to portray analog-like warmth of Teardrop that should be there. Tape hiss doesn't add atmospherics either and is just “there” as background noise. Kick drum not very obvious as a kick drum either, also lacks distinction. Lacks percussive-hit drive into belly drums of Inertia Creeps as well. Drums sound slow and lack the fast vibration decay as heard on OII/BHSE. Dark atmospherics & ominous sound of track totally not conveyed by HE-400 either. 3D's vocals also lack a heavy intonation.

 
The Prodigy - The Fat of the Land
Infected Mushroom - Vicious Delicious - "Becoming Insane", "Vicious Delicious", "Change The Formality"

1. Bass on HE-400 is low but also sounds very boring. Has quantity, but lacks "motion" and power—i.e., drive/punch/impact. Not tight either and is semi-plodgy. Sort of blobby & ploppy. Almost excessively ploppy depending on music.

 
Helloween - 7 Sinners - "Who is Mr. Madman?"

1. This recording especially shows faults of HE-400—drumming is barely noticeable on it. Shoved too much to background and doesn't sound like an integral part of the music. Polar opposite of something like AD2K which brings drums to extreme foreground. Bass guitars also completely lack fullness. Track completely lacks excitement of AD2K.
2. For metal music specifically, HE-400's frequency balance skews more towards guitar string plucks/vibrations. Huge lack of general bass fill to bass guitars and vocals that more often than not offsets the intended atmosphere, so most tracks don't have an appropriate "metal" sound.

 
Porcupine Tree - In Absentia - "Blackest Eyes", "Lips of Ashes"

1. HE-400 lacks heavy/full sound that would add more to music. Guitars stick out too much in mix. Bass guitars detracted too much. Separated, diffuse sound lacks cohesion. Opposite of Grado-like where the band is close together and upfront. HE-400 splits the band too far apart. Treble is the aggressive element on HE-400, not the band's bass guitar as it probably should be.

 
Beyond Twilight - Section X - "The Path of Darkness"

1. HE-400 shoves male vocals to background too much and recesses them too much as well. Lacks heavy, dark sound on HE-400 that should be there.
2. Not sure HE-400 would be ideal for black or tech metal due to lack of mid-bass & mid-range (male vocals too recessed, bass guitars detracted from too much as well).

Recently i received a new set of HE-400s and took them for a spin.
I never made it past the first lap, so its time for the review.
I found their sound to be a combination of overly flat mids and spiky distant trebles awash in a sea of syrupy bloated
bass response with a touch of darkness throne in to hide any hint of presence or clarity.
I use a Woo Audio Fireflies and a ResonEssence Concero HP and a Maxxed out version of the discontinued Headroom Max as my sources, so, im not under-powering the HE-400s.
If you prefer overly flat mids and thick bass, then these are your best buy.
On a positive note, as i define the HE-400s sound as bassy with muddy mids, , they can also be described
as lush, rich, incredibly thick and wide, and very very warm......like a bear hug of low mids around your ears.
Sound-stage is impressive.
One thing is for certain, after you use the HE-400s for a while then change to any other headphones you own, your other headphones will ALL sound smaller.
Much smaller.
So, consider that as the other impressive caveat that the HE-400s can truly offer you along with the very nice sound-staging.
Do they sound bad?......No, not at all.......they just sound thick, flat, and wide.
Another way to think of their sound is if tubes in a headphone amp are very old and worn out and soft sounding..., that would be a way of describing the sound of the HE-400s...... very soft, very smooth, very round, very old analog.
You keep thinking, "wow, these could be so great if i could just add some upper mids and some treble".
And somehow the HE-400s are able to make their flatish - thickish- soft and round type of EQ tonality work, ,,,but that does not mean you have to like it.
I suspect that as these phones need power to make them speak, that many of the reviews you read whereby they are described as "bright" or "shrill" can be explained by the user trying to power these with an Iphone or some similar type device
which is starving the HE-400s and in that state they are going to sound brittle, especially at the top end.
However, if you give them the power they need and crave so that they can produce as they should, then you are will discover that they sound quite buttery smooth and very warm and thick and dark.
I like them, and i appreciate their sound, but my particular need is for more clarity in the mids and upper mids so that the music does not sound laid back and creamy smooth.
The HE-400s are nice cans, and worth the money, but be certain you are looking for their sound, which is nothing at all like a set of good dynamic open back headphones like the wonderful Sony MDR -MA900s.

Positives - clean extended, balanced bass. Lacks the physicality of an LCD-2, but that's not unexpected.
 
These are large, heavy headphones, that I found surprisingly comfortable to wear  when used with the velour pads. As reference, I have a small head, am not particularly sensitive to pressure on the top of my head, but am quite sensitive to pressure around the ear. For me, these were way more comfortable than I expected based on experience.
 
Build quality of the headphones seemed good - stock cable cover (not the cable itself)  was already separating at the Y junction however (purely cosmetic impact but not a good thing).
 
These headphones seem to be generally well regarded, but for me there was one factor that made them unusable - the treble. Fair disclosure - I am not a fan of overly bright treble, however with the HE-400 something beyond simple brightness was happening - almost a resonance effect in the highs. The impact for me was that listening to the HE-400s for extended periods made my ears hurt (beyond simple fatigue).
 
In some other posts, I have read about "tizzy treble" being tamed by carefully tightening the headphone cable connectors (which have a PITA design). This could have been my issue, but if it was it's certainly a design flaw. I could have had a bad unit, or my unit may have sounded as designed - I don't know. I do know that I could not listen to them for extended periods of time.
 
These were known good HE-400s without previously discussed (and now long corrected) build issues.

Hey guys!

I know this is hardly the first review of these to ever be posted and I'm pretty sure everyone has covered all of the bases by now, but I've decided to throw in my two cents as well.

Introduction:

This is my first review here, so please don't lynch me.

I've owned these for two years and they have a special place in my heart as that one gateway drug that led me, not only to planars, but also to the higher planes of audio... Or so I like to think. Things have changed in the past two years and if you are looking for a good value, open-back planar, this is still a decent choice, but you might want to just pick up the HE-400S, since it has many improvements over the original.

Build Quality:

Ok, so to get this understood right off the bat - the build quality is good. It is. High quality material was used, the headphones themselves are mostly metal, the headband itself is also metal with a leather exterior.

However the design is not great. So to re-iterate, we have high-quality components, which have not been put together in the most ingenious of ways.

While the headphone itself is very sturdy, it has its issues:
 

1. The metal support for the headband si connected to the metallic casing of the driver through a screw on each side of the driver's casing. Now, the problem with these screws is that they have an uncanny tendency to unscrew themselves, so you have to screw them back in, which is quite frustrating. You don't even need to move around too much for it to happen, but it does.

 

1. The cable connectors... Ah, the lovely, lovely Hifiman solution for cable connectors (thank God, they've changed these with the newer models). They're something similar to reverse coax connectors, but I'm not really sure what. Either way, as the metal headband support screws, these also unscrew all the time, which is very, very frustrating and very damaging to the cable, in the long run.
   
   This can easily damage the cable as you need to rotate it to screw it in. Sure, you can rotate it in the other sense to compensate for it, but most of the time you're not going to get roatate in the opposite direction exactly as much as it needs to be screwed in and that will cause tension in the cable, which, in time, will damage it. For example, my Canare 3m cable died after about one year of usage and I had to replace it with the Silver-coated OCC 3m cable from Head-Direct
    
2. Stock pads constrict the sound and are not very comfortable. I'm sure that many of you are quite familiar with the "pads change the sound" phenomenon and it's true. The stock pads seem to take out some of the depth of the sound, it's like there's a very, very thin layer of plastic between your ear and the headphone.
   
   Additionally I spoke about the comfort. I am somewhat biased towards velour pads, because I like them more, due to not having them stick to my ears after long listening session.
    
3. Another issue is the weight that so many planars have. The HE-400 weighs about 440g, that's a little more than Fostex's T20RP MK3, which weights 328g and the Oppo PM-2 which weighs 380g. Additionally, the Newer HE-400S only weighs 350g.
   
    
4. The headband is not self-adjustable. I know a lot of people don't have a problem with that, but I prefer those, because they usually adjust accordingly, so I don't end up moving them by mistake and then not having the proper fit on my head and wondering what's wrong for a while... I imagine not many people run into this problem, though.

 
 
Sound Quality:
 
Ok, now here's the most important of them all. The sound quality.

Setup: I'm currently using my desktop PC, using a Oehlbach XXL DAC Ultra connected via USB (32-bit, 192khz) into which I plug my HE-400 directly. I have also used them with a Creative Sound Blaster Zx and a Asus Xonar Essence STU, but I will just talk about how it sounds with the Oehlbach, because it is the most fresh in my mind.

I'm using Foobar2000 as my player and my files are mostly FLAC or WAV, but I've also thrown in the occasional mp3.

I listen to all types of music, so I decided that I'm going to "audition" them and present their capabilities using multiple genres. Some of the songs I used are:

Michael Jackson - Thriller
Aerosmith - Dude looks like a lady
Queen - Keep yourself alive
Disturbed - Indestructible
Jesse Cook - Mario takes a walk
Queen - Another one Bites the Dust
Nova Menco - Journey
Joe Satriani - Surfing with the Alien
Steve Vai - Earthquake Sky
George Benson - This Masquerade
Guns n' Roses - Nightrain
Diana Krall - Fly me to the moon
Lee Ritenour - Night Rhythms
Ola Gjeilo - Ubi Caritas
Funkadelic - Maggot Brain
Infected Mushroom - Heavyweight
Pink Floyd - Comfortably Numb
Christina Aguilera - Hurt
Frederic Chopin - Grand Valse Brilliante (Interpreted by Valentina Lisitsa)

The tracks which I found more relevant are in bold and I will provide an explanation of why I found them to be important to my listening impressions.

So, right as you start listening to these, you can hear the immense soundstage and detail retrieval, they are really great, especially if you come from a closed-back headphone. Which I did, I tried them right after work, where I use a AKG K66. Not much of a comparison, I know, but it makes the WOW factor all the more obvious.
 
Michael Jackson's Thriller is a big-time hit for me. I've always loved this song, ever since I was little, but hearing it on a pair of HE-400 is completely different than hearing it on... Say, my old NEI television set, on MTV. I love this song and I listen to it when I try out headphones because of the great imaging and spaciousness it provides. From the start, when the synth and bass come in, you can tell that everything has taken its rightful place, being set just where they're supposed to be, offering a beautiful, beautiful imaging. It's not just once I've found myself pausing after the howling of the wolves, wondering what my neighbor's dogs are doing and why they're going nuts... Then I just realize that it's my music.

Aerosmith's Dude looks like a lady I use due to it's intermittent stereo sequence at that start. I generally blast the volume really high and see if there is any noise coming in between the guitar segments, in the quiet passages. While I did hear some noise, I later found out that the matter lies with my Oehlbach, not with my HE-400.
 
Queen's Keep yourself alive is a great song to show off the nice, smooth mids and incredible detail retrieval of this headphone. As soon as the song starts, you hear the guitar. You hear the pick strumming the guitar strings. You hear the edge of the pick grinding against the edges of the thicker strings' exterior metallic wrapping. It's fantastic to hear this much detail and it is quite soothing.

Indestructible, by Disturbed is, by far, my favorite workout sound... But as you can imagine, I don't really go to the gym with my HE-400, I simply enjoy the song at home, sometimes and that truly isn't difficult to achieve, as the HE-400 brings a great bang and slam with its bass, as soon as the instruments kick in. You can feel their "raw power" and their energy right off the bat, but sometimes it gets a bit too harsh (more on that later).

Another one bites the dust, by queen, I find to be a great tool for listening to bass and sub-bass and boy, does this headphone shine here. The bass is nicely balanced and controlled, without being bloated or feeling artificial in any way. It has depth and it packs quite the punch. It's full and it's not the type of fatiguing bass I've seen with some very V-shaped response headphones. I truly enjoyed it, despite being more inclined to a more mid-centric orientation.
 
Earthquake Sky is on this list because you can easily hear the nice slam of the drums, which really puts the lower range of these headphones to value.

Nightrain is just on this list because it's my favorite song of all time and it proves that, even though I love Slash a lot as a guitarist, Izzy Strandlin was quite under-rated and its that specific underdog effect that makes the first solo of Nightrain my favorite guitar solo of all time... Also the highs sounded harsh and edgy. That was unfortunate, this is one of the few times in which the high quality version of the recording was a poorer experience to me than the low quality mp3.

Funkadelic's Maggot Brain is a song I got into when I was in high school, just learning guitar. This is also one of the first lengthy solos I have ever learned, so it's quite special to me. Half of it sounds as smooth as a summer lake at dawn, really showing how the mids are well-balanced within the whole sound, showing off a very detailed sound. As for the other half, the higher-end of it all, it sound abrasive, if felt like sandpaper was being rubbed somewhere close to my ears, at times.
 
Infected Mushroom's Heavyweight is good as it takes you through so many sound, building a complex imagery around you, showing you how well individualized this headphone makes everything, giving proper air between each instrument and having everything settle in just right.
 
Christina Aguilera's Hurt, now that's a song I really enjoy and its depth gives me goosebumps every time. It's about regret, it's about not saying what you were supposed to, what you wanted to, at the right time, it's about missing out on important things in life, like family and the loss of a loved one and also about the difficulty to move on after such a tragedy, it's about... Those damn high peaks that ruin everything. There are seriously some weird high spikes in the upper range of the spectrum which can be heard throughout the song. There is also some slight sibilance and just a general sense of unwanted edginess and this time the fault is not with my Oehlbach, nor was it with my Creative X-fi Xtreme Music, nor with the STU...
 
This, my friends, was the biggest flaw in sound quality I found with the HE-400. It can be partially resolved by equalizing the headphones somewhere between the 9-11k, but nobody really wants to do that. Nobody wants to spend a lot of money for a headphone in order to make it sound right. Of course, I'm not saying it sounds bad, but flaws like this can be quite bothersome, especially when they're so obvious in songs you really enjoy.
 
Additional Notes:

They're easier to drive than most planars, but I wouldn't recommend using them on your phone.
They're not portable and are not meant to be, they don't fold, they're not closed-back, they don't have a carrying case/pouch.
The HE-400 can be used as a small, mono speaker if you have a powerful enough amp.
Hifiman HE-400 are moddable, they can be modded in many different ways in order to tweak either sound or comfort. I have not tried any of these mods, all I have done is change the pads on mine and I'm happy with the result.
They come in a cardboard box, with a plastic support, but I don't care since I don't want to pay a premium for the packaging anyway.
 
Conclusion:
 
These are a beautiful way to into things, whether it is high fidelity audio, planar magnetic headphones or just another plane within the Nirvana of good music. Sure, they're a bit clunky, a bit uncomfortable, but they provide great value for the money. The sound quality is great, but it could be a bit better. They'll always provide a good experience, but most of the time they'll provide a great one.
 
Within the context they were released in, all those years ago, I would give them four stars, but now with the existence of the much better, many-times-over improved 400S, I give them  three stars. Mounting that up to an average of three and a half stars, which I think is fair.

Apologies if I forgot to mention anything (I'm writing this while at work, don't tell my boss!), I will update if I find it necessary and may return to post some pictures of the headphones.

Thanks for reading, let me know if you have any question (though I doubt it, at this point).
 

First of all, I was not running these from appropriate amplification at the time (Audigy 2 ZS Platinum Pro breakout box). Secondly, I have exchanged these for some other phones, and have only had them for a few days (also potential defects). Third, I am relatively new to the hifi scene. Therefore I have deemed it fair to give them 3.5 stars in order to not ruin the average. I felt I had to after that guy gave 1/5 stars for some reason.
 
With that out of the way, onto the review.
 
EDIT: Please ignore the scales to the left, they do not reflect what I think. I can't change them for some reason.
 
Audio path:
FLAC 44.1 16-bit or MP3 V0/320, various genres -> JRiver Media Center -> ASIO -> Audigy 2 ZS -> Platinum Pro breakout box -> HE-400
 
Previous phones i've owned are the Sennheiser HD202 (broken, piece of crap) and HD555's with the foam mod. I had the former for about a year and the latter for 3 or so.
 
Design / Build

1. These are Revision 2's.
2. Personally, I think these look fantastic. They are how I would design headphones if given the opportunity. It reminds me of something like a sleek old muscle car with a modern facelift. The colour may look showy to some in photos, but in real life it's not quite the case. It's a nice, dark shade of indigo blue that doesn't look gaudy at all. In fact, they look much more attractive and unique than the HE-500's with its boring grey scheme.
3. The housing appears to be some cheapish plastic, unfortunately. The paint job seems decent though.
4. The mesh can be removed fairly easily by pulling out a plastic retaining ring with your fingernails. This adds some nice modding options (diamond/criss-cross grills anyone?) that can potentially affect the sound. You could probably paint the ring to give the phones some accents too.

1. Apparently both drivers are wired in reverse polarity (I couldn't confirm this because I didn't have a mic). A few people argue that it has a negative effect though I can't say for certain.
2. Cable is removable, though uses unusual mini coax connectors for the drivers. I guess they used them instead of mini XLR for cost reasons.
3. Stock cable is not horrible as everyone makes it out to be (coming from HD555's, anyway). Bit too long and stiff though.
4. I feel that the connectors detract from the aesthethics (and function) however, and they should simply be sticking straight out the bottom of the housing; instead of being recessed (makes it more difficult to screw on the cables as well).
5. Earpads are a bit fiddly to put on, and they spin freely (not a big deal).
6. The round things with Hifiman logos that hold the arms for the housings seem to do a decent job of retaining its position.
7. On a whole, these don't feel or look like cheap headphones. They seem like they would take much more of a beating than the dynamics i've owned, and I don't see anything that would crack in everyday use (unlike the HD202 and HD555's). Not sure how they would cope being dropped onto a hard floor from waist height however.

 
Comfort / Fit

1. Repeating the words of everyone else, they are heavy. But when I first took them out of the box, they weren't as heavy as I thought they'd be.
2. Weight only posed a problem in regards to pressure on the top of my skull. It was probably the most annoying thing comfort-wise about these. I never experienced any kind of neck pain.
3. Headband padding is some faux leather and way too thin for my liking, especially with the weight of these. It was somewhat more bearable when I ripped the pleather padding off my dead HD202's and stuck them on though
   
4. Included earpads (pleather) are not as soft as i'd like and made my ears hot fairly quickly. The optional Hifiman velour pads were actually stiffer than the pleather ones (???) and definitely not up to scratch to my HD555's stock earpads, but at least my ears didn't get too hot. Overall, they did improve the comfort noticeably though (and sounded a bit better too).
5. It's possible to mount earcups from other manufacturers on. I've seen people mount Lawton Audio slanted leather cups and they look awesome.
6. You can bend the headband to fit your head better (manual says so), though I felt no need to do so.
7. All in all, actually not as uncomfortable as some people make it out to be. But I am constantly reminded of its presence, which detracts from the listening experience sometimes.

 
Sound

1. This is probably the part of the review I feel the most uncomfortable with as a budding headphone enthusiast. Bear with me. Also note that they probably weren't amped properly.
2. I was excited, so when I first got these I soon plugged them into the only source I had my hands on at the time: Galaxy S II (with varying genres of FLAC files running through PowerAmp player). I did not expect anything amazing at all. And I got exactly that. Nothing to speak of. I could only just barely get them loud enough at max volume. To be expected of a phone, even though HiFiMAN says it's good enough for portable devices.
3. I immediately plugged them into my Audigy 2 upon arriving home and started playing my favourite track: Give Life Back To Music by Daft Punk. I wasn't blown away, though I wasn't really expecting to be. I wasn't blown away when I went from my HD202's to HD555's either though.
4. I then started to play some ambient music (stuff like Jonn Serrie, Steve Roach) because I wanted an idea of how immersive it could be. Wasn't blown away here either, but I noticed the soundstage seemed noticeably wider than my 555's, though the depth was about the same I think.
5. Deadmau5 - I Remember - to test the bass impact and vocals. First of all, I am not a basshead. I was actually quite surprised here. When I heard the pulsating bass, it was strange, but not in a bad way at all. It sounded very much like a subwoofer, yet I felt no rumbling at my feet. I actually went to check if I accidentally turned my 2.1 set on. Still, they could have used a touch more bass quantity, though amping them properly probably would have done the trick. As for the vocals, they seemed less than impressive to me. They didn't really stand out and sounded a bit hollow to my ears.
6. I enjoy some classical here and there. Played some woodwind stuff. Problem: Certain notes were quite uncomfortable to listen to, I blame the treble spike.
7. I tested the bass further by doing some frequency sweeps within 20-200hz. The bass extension was truly something to behold. It really was like having a subwoofer mounted to your head (minus the physical rumbling).
8. Throughout all that, I experimented with various angles and distances between the drivers and my ears. A couple of things to note: there was significantly more bass quantity when I held them about 2cm away from my ears. Slanting them inwards (like on the Audeze LCD-2) seemed to reduce the 'nasal' tone significantly and make them sound more speaker-like. In short, they are quite sensitive to positioning compared to most dynamic phones.
9. Played some games, namely Mirror's Edge and Battlefield 3. Things like gunshots and explosions sounded lacking and hollow compared to my 555's, also I didn't feel as if anything took advantage of the bass extension. Then I wondered why the sound positioning didn't seem as good as the Sennheisers. Sounds coming from the front did not sound like they were quite in the center for some reason. I concluded that they weren't suitable for this purpose and I simply went back to my 555's for gaming.
10. Watched some video reviews on YouTube for a bit. Voices didn't sound right. I then swapped over to the 555's. It sounded like it was in the center as it should. I was confused. Played some movies to triple check. Same problem. I was worried. I posted about it on Reddit, someone believed it was a driver mismatch issue.

1. At this point I noticed my ears were tired and ringing more than usual (already had tinnitus). I didn't have them much louder than I usually have the 555's yet it fatigued my ears far more for some reason.
2. I'm not sure what to think of burn in yet, but I left them burning in on my desk in a cardboard box at slightly higher than normal listening level for about half a day. No idea if it made a difference soundwise. But during the time I felt that familiar fatigue in my ears. I feel there's some kind of resonance or something that I can't put my finger on, causing strain to my ears. This was probably the biggest problem I had with these, with the sound positioning issue following very closely behind.

 
Conclusion
I really wanted to enjoy these. They are aesthetically pleasing and I was very excited about diving into the world of planar magnetics. Unfortunately, quality control issues and a bizarre fatigue problem ultimately stopped me from enjoying them. That aside, and truth to be told - most of what is going to be coming out of headphones for me isn't music, as much as I am very enthusiastic about the stuff. I want general purpose headphones for computer/entertainment use that is decent at everything - music, gaming, TV shows and film.
 
I think I would have kept these if I had a dedicated listening setup for music. Heck, I don't even have a headphone amp yet. I have since replaced them with DT880's (Premium 600ohms, yes I need an amp, just trying to be future-proof here). I think they are a step up from the HD555's in every way for what I use them for. However, I do miss the HE-400's in a lot of ways. They provided a speaker-like experience. They sounded full and allowed you to feel the music, and just had this charm about them I can't put into words.
 
Would I recommend these headphones still? Yes. These issues might not even bother you at all.
It almost ticks all the boxes, but just misses a couple of critical ones for me.
I eagerly await a successor so I can give HiFiMAN another fair go.
 
I hope this review, though somewhat unrefined, helps people.

sorry my English is Google translate

The sound of these hifiman immediately like it or hate it.
They have a strong character, perfect bass, brilliant highs, medium tone mind incorrect.
A few years ago I was involved with live recordings of classical music and I used the stax lamda pro (magic but delicate) and Sennheiser HD 600 (less magical but tonally correct) as monitor of post production.
After so many years I decided to try this hifiman hoping it was a mix between strax and Sennheiser.
Ok I was wrong, hifiman has a different sound.
For two weeks I sailed between Acdc, metal, in exaggerated volumes.
Then I got the Audio Gd NFB 28 and headphones were taken off, especially in balanced.
Too bad the rest of the music I was interested less than usual, then I realized that the particular signature sound port to listen at high volume that kind of music.
Loreena McKennitt's not good! His voice changes tone is darker, the musical instruments that are riding the midrange suffer.



Il suono di queste hifiman piace subito o lo si odia.
Hanno un carattere forte, bassi perfetti, alti brillanti, medi timbrica mente scorretti.
Qualche anno fa mi occupavo di registrazioni live di musica classica e usavo delle stax lamda pro ( magiche ma delicate) e sennheiser hd 600 ( meno magiche ma timbricamente corrette ) come monitor di post produzione.
Dopo tanti anni ho deciso di provare questa hifiman sperando fosse un mix tra le strax e le Sennheiser.
Ok ho sbagliato, hifiman ha un suono diverso.
Per due settimane ho navigato tra Acdc, metallica, a volumi esagerati.
Poi mi è arrivato l'Audio Gd Nfb 28 e le cuffie hanno preso il volo, soprattutto in bilanciato.
Peccato che il resto della musica mi interessasse meno del solito, poi ho capito che la particolare firma sonora porta ad ascoltare a volumi alti quel genere di musica.
Loreena McKennit Non va bene! La sua voce cambia tono, è più cupa, gli strumenti musicali che sono a cavallo della gamma media soffrono.

The price to performance ratio of the HiFiMan HE-400 is truly exceptional. The clamping force of new head band is tight and requires break-in. I prefer the the plush pads over stock pads for comfort. Once HE-400 is broke in, like a pair of old boots...they become comfortable but not super comfy..due to the weight of these cans being on the heavier side. 
 
Equipment used for this review
 
HiFiMan HE-400
 
HiFiman HE-300
 
Grado GS1000e
 
Bose ae2
 
Decware Zen Head amp
 
Emmeline "The Black Bird" SR-71A amp
 
Schiit Valhalla 2 amp 
 
Modifies Play Station1 CD player
 
iPod classic 160gb
 
iPhone 4s
 
ALO Audio 30pin line out dock cable
 
AudioQuest cables
 
All tunes sourced at CD quality bitrate 1,411 kbps, iTunes, Tidal music player, CD's, WAV files
 
 
 
 
 

 

I've been wanting a bassy open headphone for a while and after a bunch of research I decided on the HE-400. I normally have no interest in high end headphones because they lack bass, but from what I've read the HE-400 will give me a decent amount.
This is a quick impression from a basshead's point of view since there's already plenty of reviews, but most reviews are from audiophile who don't normally use and listen to bassy headphones.
I used the new FiiO E12 (the no bass version) for this impression with flat EQ on my iPod video 5.5G.
I use this set up because I have multiple listening spot in my house.
 
Value:
Definitely worth the $400, I got mine from Justin @ headamp.com for $335 shipped, factor in the sound and build and it easily worth more than $400.... If you're an audiophile. For bassheads it would depend on how much bass you're looking for.
 
Audio Quality:
I love the sound of the HE-400 but I do wish there was a bit more rumble, but I wasn't expecting it since it's an open audiophile headphone. The sound quality wasn't the leap in sound I thought it was. It's better than what I previously had but it wasn't that much better it's more of a different better. To my ears the HE-400 kinda sound like the portapro (which I love btw) but better everything. The mids are great and highs are nicely details without piercing my ears like most audiophile headphones. Vocals are nice and clear. 
Now for the bass. It's good bass, clean, fast and just loud enough but no way is it basshead level.
For audiophiles who don't normally listen to bassy music or use basshead headphone will call the HE-400 bass heavy. For us basshead it's not even entry level. It's nice bass but lacking in quantity even with a bass boosting amp. The FiiO E12 with it's weak bass boost did not do much in uping the bass quantity. The quality of bass is great though.
 
Design:
I love the design of the HE-400, it easily one of the best looking headphone I've used. Build quality is solid too. The cord is the only issue I have, it's too long and too stiff.
 
Comfort:
I personally did not have any issue with comfort. I had mine on for 3 plus hours without any discomfort, but I don't normally have issues with uncomfortable headphones (except the V-Moda crossfade and Shure SRH750DJ) so take what you want from that. 
 
Overall:
I am a basshead but my demand for bass is not what it use to be. I don't want bass all the time, but when I'm in the mood for bass I want a lot of it. The HE-400 is good enough for normal listening session, but when I'm in the mood for some serious bass I usually skip the HE-400. When I first started here I got a lot of recommendation from audiophiles saying this and that has a lot of bass, but when I buy them they lack bass big time, I realized most audiophiles have a very different view on bass. What's lacking to bassheads are a lot to audiophiles. The HE-400 falls into this category.
Overall I'm happy with the HE-400. It sounds great and even though it's not basshead level, the bass is good enough.
I'm currently looking into other amp that will max out the HE-400 so I might update this later, but for now the E12 is not doing the job I bought it for so back it goes and will be replaced by the C5.
 
 
EDIT:
[02/20/2013] Today I decided to use my E07K, I max out the bass(10) and gain(12) and the HE-400 gave me a good rumble, but once I up the volume to about 40 (65%-70%) it started to distort. 
At least now I know the HE-400 can give me a bit more bass quantity with the right amp. The E07K is not the right amp, SQ suffers when using this amp.
I have come to a conclusion, this headphone will never truly satisfy a true basshead

First things first, there is a simple trick that solves all the complaints about the cable connectors - simply rotate each 720 degrees counterclockwise to build up some torque before you screw each one on clockwise.  Since you only need to screw 540 degrees clockwise to fasten them, the extra twist remaining in the cable keeps them securely fastened without having to overtighten.
 
The build is nothing special.  Yes the R/L markings rub off.  Also the screw placement is oddly asymmetrical.  Materials are not luxurious, and comfort is just average (though comfortable enough that I can enjoy them for hours on end without distraction).  They are somewhat heavy.
 
Bass is incredible.  In this price range, I am unaware of any headphones with this kind of bass extension, impact, and natural sound.
 
High mids are a bit recessed (less so with the velour pads), yet the mids as a whole remain clear, detailed, and vocals show great depth.
 
Speed, transparency, imaging: all strong suits.
 
These headphones absolutely shine with jazz, rap, electronic, funk, rock, and pop.

 
 
My take on these cans:

I've had the HE-400s for about year, and am now running them through a V-Dac II into a Burson soloist. 
Argon 5057 Cables between the amp and dac. My pair have the revision two casing (White-ish).

For modifications, I swapped pleathers for velours and removed the mesh that was glued onto the grills, no problems caused from that so far so thumbs up. It would probably be a safer bet to keep the hifimans under cover once in a while so they don't collect too much dust. These two mods are a must for anyone wanting to get the most out of these cans, however I wouldn't recommend the mesh mod if you have an already bright system as it slightly adds more treble and contributes to more fatigue (at least that's what I have observed). 

Genres I listen to: Metal of all kind, female vocals/acoustic, pop, dubstep & electronic. I can only comment on my own system because i've never owned anything else. The sound you get from these is very full, bass is perfect, prominent in the mix but not too much that it takes away from anything else, mids are really nice, gives guitar and vocals that extra richness. I have had to EQ the highs a tad, because these can get harsh with some less stelar recording mixes, Soundstage and imaging is good, you can pinpoint all the different elements in the song. One of the only negative things that I can find in the sound (and I may be over-emphasizing this) would be the really wide soundstage (more on the sides and less in the centre) that may make music that's played on a stage seem less realistic. This doesn't really bother me but if you're really looking for that speaker-like soundstage, other cans may do this better. This wide soundstage works perfect with more digital music like electronic etc.

The HE-400s build quality (driver casing/headband,etc) seems really durable, but these cans really need some refining. There are some things I feel could have been better, the 'Hifiman He-400's logo paint has started to fade, the R/L channels have completely dissapeared over and the cable has started to ware right before the connectors. Also, comfort is one of the big cons of this otherwise, really great sounding headphone, so take this into consideration (I am looking into upgrading to the revised models, HE-560).

What else can I say..I wouldn't say this headphone responds alot with better equipment, probably because of its efficiency. The V-Dac and Burson amp did make subtle changes but if you're budget is limited, going with less expensive options won't set you far away from the headphone's full potential. Only thing I would look into a headphone from this would be more detail, less brightness, more realistic imaging, and refinement in build and comfort.  I think synergy is pretty good, the Burson Soloist gives the HE-400's all the power it needs (does not need this much), and the Musical Fidelity Dac adds warmth so anyone looking at this setup, go for it. Conclusion: All rounder cans, great value and a nice step into the audiophile world. Feel free to message me about the headphones, dac or amp. and thanks for reading my review.

EDIT: Hifiman has released two new models, the HE-400i and the HE-560, these are discontinued.
 

Preface

The “low” end of the Hifiman classics that is recognized alongside the lineup of the legendary HE-500 and HE-6. You rarely see these on the used market nowadays since their release about 7 or so years ago (before I started even in the hobby). I’ve read posts from previous owners (and current owners) about the touted bass on these as being fun and enjoyable when compared against the HE-500, and does not reach the bass quality of the veneered HE-6 when powered through speaker taps. This made me really curious about the performance of these when compared against my HE-500 and was fortunate to purchase one recently at a good price.

I’ll skip over some sections given that this is a used, discontinued model; there isn't much to talk about with regards to other tangibles (i.e. packaging, accessories). When I got this, it had a broken original SMC to 3.5mm cable, had the stock velour pads, and the HD650 padding stuck on the headband (similar to my HE-500). With those out of the way, let’s get to the review.




Build and Comfort

Build quality is classic Hifiman; decent looking and heavy. There have been reports of this style of headband failing because the glue holding the headband sliders eventually weakens - I fortunately have yet to experience it on my HE-500, and this doesn’t seem to be the case with the HE-400 I bought used. So count me on the statistic of “still in working condition” Hifiman QC count.

I had the HE-400i that was released in 2016 with the suspension strap and on a personal note - I preferred that headband system because of the weight distribution being better compared to the singular band present in still current models like the HE-4XX and HE-5XX. That aside, the headband is reasonably comfortable overall… for the first couple of hours. After that, I feel a hotspot at the top of my head, which I attribute to poor weight distribution on this particular style of headband. I feel the same with the HE-500 and this weighs slightly less than that.

For the pads, the stock velour is just plainly irritating to my skin. It just passes what I consider to be comfortable. I’ll cover a short section about the sound when used with the stock velour, but I immediately replace it with the Dekoni Elite Velour for Audeze that I have and used for my HE-500 (currently in hibernation while I play around with other cans). How do the Dekonis feel? Predictably, much better and I’ve since then been using these as my pad of choice.


Amplification

These are rated with 92.5 dB sensitivity and 35 ohm impedance. This is neither demanding nor easily driven - about smack in the middle of having enough volume out of a decent source, but likely not enough headroom for highly dynamic tracks at louder than my preferred listening levels. They can run off an iPod just fine without me noticing any loss of quality. Heck, I don’t go past 9 o’clock on the JDS Element dial, and only go around 10 when EQ is applied. You don’t need a high wattage output amp for this based on my experience. Take that as you will as there are others who would slide in their comments about using speaker taps improving the bass and such - I am not one into trying that route so you can discuss with those individuals about them.

On a side note, for people’s reference, I usually listen anywhere between 60 dB - 75 dB.


Sound

As I mentioned in the comfort section, I did not find the stock velour very comfortable and instead chose to go with the Dekoni Elite Velour for Audeze. If you wanted a short summary of how the stock velour sounded to my ears, here’s the TL;DR: treble can be sibilant at times, bass has decent impact but texture feels lacking likely due to seal or decay and tends to bloom over midrange, midrange definition is overall good - however, it has peaks in weird places that makes some background instruments more noticeable at times and the vocals subdued, but at different parts of a song. I can’t explain it any better than that. But my takeaway is that stock velour has a weird V-shaped tonality. On a final note, there are those who claim that there has been a revision of the HE-400 at some point. I will say I cannot give more details on that and the different revisions as I didn’t look into it too much.

Since comfort and seal was an issue for me, I opted to go with the Elite Velours I used to have with the HE-500 - so essentially both my HE-400 and HE-500 are evaluated with the same pads (talk about consistency). The review moving forward consists of the HE-400 with the Dekoni Elite Velour for Audeze pads installed.

Further, I have not been able to find a reliable frequency graph measurement of these, so this will essentially become a completely subjective review without confirmation to my ears of what I hear. Guess this is the most subjective review I’ve written and you can put as much salt as you want with it, but I’m winging it so let’s go with it.

My music testing mostly involves modern tracks, OSTs, classic rock, 70s to 90s pop.


Overall Sound Signature

With the Elite Velours, the HE-400 is warm sounding, similar to the HE-500 but with some distinct differences (which we’ll touch later). The overall balance is decent in my opinion, bass comes across as warm, midrange has good definition, treble has enough energy to not make the tonality dull. I would classify this as warm-neutral with no EQ and is fairly enjoyable for modern tracks.

Bass

• Extension is good, but slightly behind the HE-500, rounding up to around 35Hz or a bit higher
• Bass is quick in attack, but texture is a bit unrefined, like they’re a bit loose. I think some would describe this as lacking “tightness”. This may have something to do with decay being slower compared to others I’ve heard. You can still distinguish the individual bass notes though
• Bass extends a bit to midrange, giving off a warm transition to the lower midrange
• Bass impact/slam is good, but I would have preferred more. Impact is a touch less than the HE-500 from recollection, and lesser than the Focal Clear I had before.

Midrange

• Lower midrange I feel has decent texture and definition. Male vocals have good quality and weight
• With the bass extending its transition to the lower midrange, this seems to add a layer of thickness to instruments like electric guitars, which makes them slightly incorrect sounding
• Upper midrange is a bit weird. Some notes are more prominent than others on certain tracks, which I find odd because other headphones don’t bring out such pieces in a song. Some brass or violin notes will come out with more volume than say the lead vocal at certain parts of a track, which I don’t experience with others like the Clear, DT1990, HE-500 and such. Not sure if this is what others would typically describe as ‘wonky’
• Piano notes have good texture and definition. *Some* female vocals seem to lack weight, while others sound fine
• Vocal transition is good, similar to the HE-500 and DT1990 in quality, but maybe just a touch slower and not as smooth in transition

Treble

• Treble air quality seems hindered a bit, like the 10kHz region is more subdued than preferred, adding to the overall warm tonality
• Presence region (6kHz - 8kHz) has enough energy to give liveliness in a song, but seems to have some lingering effect on the consonant range and some ringing effect of some sort
• This presence region makes some consonant ranges and cymbal crashes sound sharper than what I prefer, but it’s not in the level of annoyance as the Focal Clear or TH-X00
• Overall passable treble balance leaning towards the warm side with a slightly peaky presence region

Detail Retrieval (Resolution) and Dynamics

Overall good, but maybe a step behind against the HE-500 and DT1990 in stock tuning with the Elite Velour. There seems to be some weird peaks and dips in the midrange to upper-midrange section that’s causing some details to share the center stage with other instruments at different times. Once EQ’d, it fixes this unusual detail retrieval presentation to something that sounds more normal. With EQ, I would rate the detail retrieval and resolution only a half step behind the DT1990 and HE-500.

Dynamics is also a positive for me. Bass dynamics and slam are a bit behind the HE-500 IMO. Initial leading attack on the upper midrange to treble region seems somewhat blunted, likely caused by the weird midrange peaks it has. It’s just slightly dampened when compared against the HE-500 and I would attribute the cause to be from the weird upper-midrange to treble balance. Even with the good dynamics, cohesiveness of the different instrumental pieces are great and something that makes music listening engaging. Overall dynamics is still behind the Focal Clear to my ears, as I think Focal is still leading in this technicality.


Head stage and Imaging

Like my other reviews, I don’t give this technical ability too much notice since most of the songs I listen to don’t require me to concentrate on this aspect. I usually multitask when I’m listening, I don’t often listen to music just to listen. I will say that the head stage presentation is about average, stage width = average, imaging = no glaring flaw to speak of. It’s cohesive enough across the 180 degree listening stage for me.


Timbre

Overall, a bit coloured and lacking in naturalness to my ears. There is this weird dips in the upper-midrange that makes female vocals sound a bit odd at times. Further, there is this ‘plastic’ effect that is noticeable when the presence region is reached, namely in the consonant range. I suspect this comes to the decay of the drivers that’s hinting at a somewhat plastic sound after the initial consonant range is pronounced. (What I mean by plastic effect, imagine tapping a ziplock bag and the sound of that plastic crinkle - that’s the sort of sound I hear during the decay of the consonant range pronunciation).

Instruments like piano, acoustic and electric guitar sound tonally correct for the most part. What some of the instruments lack is that initial ‘bite’, which I will attribute to the combination of upper-midrange and treble balance.

In summary, it’s not as natural sounding as the HE-500 in stock form. However, it’s not overly coloured to the point that it sounds completely incorrect. It just adds some colouration that some might find enjoyable. I certainly enjoy this type of colouration on some songs, but not so for others. The thing is, if I don’t find it consistently correct in timbre on the majority of the well recorded tracks I listen to, I can’t give this particular category a good mark. Timbre quality is just on the passing line grade for me.


EQ

As always, EQ for the most part fixes the tonality section and some of the timbre issues. The midrange to treble balance has for the most part been alleviated for me. The ‘plastic’ decay quality in the consonant range has also been reduced significantly, so only a hint of it remains with the EQ profile I use. Bass has also reduced its uncontrolled texture and over-reach to the lower midrange. It’s still not quite as impactful as say a Focal Clear, but it’s more linear sounding which I prefer. This headphone takes a lot of EQ’ing to get to my target curve, but once it reaches my preferred signature, it has been pleasant to listen to.

Among the most interesting things about the HE-400 EQ’d and the HE-500 to my ears, is that it makes voices (especially female vocals) sound like they’re not coming from a set of speakers, nor does it sound like a playback recording. I can’t quite point to it, but there is this certain sense of texture in the vocal range that makes them sound like they’re right there with you, as if they are life-like in quality. Besides these two, the DT1990 EQ’d is similar in quality for this but maybe marginally behind. Of course, your findings may vary as our experiences differ. We tend to differ in what sound texture we look for that registers to our perception of what sounds real or not.

At this point in time, I’m EQ’ing almost any headphone I get nowadays. The only exceptions so far that I find doesn’t need EQ to sound great are the HE-500, HD600 and Focal Clear. For the HE-400, I am one to recommend EQ with them. This is not to say that they are un-listenable in stock form. No. You may like the stock tonality for sure, but to my ears, the stock tuning is not something I would openly recommend to the next headphone enthusiast.


Comparisons

Hifiman HE-500

How does it compare to it’s older brother? They share some characteristics (other than their design and build quality). In stock form, the HE-400 tonality is more V-shaped, while the HE-500 is more linear sounding. The HE-400 hits my sibilance sensitivities for certain tracks, whereas it is absent on the HE-500. The HE-500 has the better extension on both bass and treble to my ears on both ends than the HE-400.

With an EQ’d HE-400 vs HE-500, I can’t say yet. The HE-500 is in hibernation for the time being as I expect my perspective will change and have this particular guilt on why I keep trying out new headphones when this is close to my ideal signature overall. Both are discontinued anyway so it doesn’t matter too much since these come every so often in the used market. Still, I would say the HE-400 EQ’d is a good alternative if you can’t find the HE-500, and I find the HE-400 the more ‘fun’ sounding of the two.


Hifiman HE-400i (2016 2.5mm version)

I haven’t heard the HE-400i in a while, so I’m only going by memory of it’s overall tonality - bright neutral. There is a presence region shout that can become sibilant at times. I like the bass better on the 400, but I didn’t really play around with EQ on the 400i so I can’t say much about its potential other than the stock form bass is quite lean in texture despite being tight and quick typical of all the planars I’ve heard so far. Head stage width is also narrow on the 400i for some reason, it could be my unit is defective or my dac/amp setup at the time (E07k/E9) is causing problems with it.

Comfort also goes to the 400i with that suspension strap structure distributing weight better.


Sennheiser HD600

One of the iconics in the headphone world. As I’ve mentioned in the other sections, if someone is looking for a no-frills headphone that sounds great all around without needing to mess with any other DSP tools, the HD600 is the choice. It has an inoffensive tonality and good technical abilities, hence why it’s been recommended time and time again despite its flaws when compared to certain headphones people prefer that’s not a Sennheiser HD6X0 series.

When an EQ’d HE-400 is put up against the HD600, it becomes more competitive. With the profile I use for my target curve and earpads, the HE-400 I find is better in almost all fronts (except for comfort) by a small margin. It’s a bit more dynamic, a bit more engaging, with vocal qualities that so far is at the top of my list. Feel free to disagree, because that means we already differ in perspective, and I’ve mentioned on my section about Timbre that this (EQ’d) and the HE-500 have vocal qualities that I find special compared to the rest I’ve tried. I'm not with the majority that find the HD600 vocals to be realistic sounding, only tonally correct sounding (if this is what most would mean by 'natural' sounding).


Conclusion

For a discontinued model made around 2012, I feel this is one heck of a bargain at its used market price (<$150). Hifiman’s double-sided planar in the HE-400 and HE-500 have some special quality to them that I find isn’t quite captured in the newer HE-400i released in 2016. I can’t say if the newer Hifimans are able to replicate it, but from most that I’ve read around, it seems the Hifiman sound is a bit different nowadays. Better to ask others who have the OG 400 and the newer ones to compare it to.

I can wholeheartedly recommend the HE-400… if you meet majority of these criteria:

• Have strong neck muscles
• Confident in doing even simple mods on them (i.e. pad change)
• Likes a semblance of V-shaped open back tonality in stock form
• Use EQ to fix flaws in the signature
• Likes a ‘fun’ and ‘engaging’ pair, however you perceive a headphone as being those two adjectives

The stock tonality is just a pass for me, and is something you might want to hear for yourself. Stock velour pads become sibilant for a number of songs I listen to, so that is an off mark for me. Further, stock tonality is not very correct sounding to me. However, at the price they can be had at the used market for less than $150, I’d still put this on my list of ones to obtain.

Overall grade comes down to the following:

• Stock tonality - 7.3 / 10
• EQ’d tonality - 8.5 / 10
• Comfort - 7 / 10
• Technical Abilities - 8.2 / 10

Because of how good I find these when EQ’d, I will be giving them a score of 4 / 5 here. Excellent sonic performance with decent comfort at the market price gets a high mark from me.

Thanks for reading my lengthy write-up.

This is one of my few reviews, Im not a type of person to give reviews when buying an item but this time I had too. I was looking for a good setting to have a portable hifi system and I knew to achieve this its not coming for cheap but also I had a budget. After reading many reviews I decided to go for these planar headphones the Hifiman He-400 and also bought the Fiio X3 to drive them with.I was so excited when I received them that I couldn't wait to try them on. But to tell you the truth I wasn't that satisfied! Yes its true you will hear instuments and clearness that with my other equipments I couldn't but I love to listen music load and perhaps without losing from quality thats why I spend around 400 Euros for them but with Fiio X3 at full power wasn't so impressed. I thought that these headphones were not driven hard enough so I decided to go for an Amp. My choice was between C & C BH  -  Fiio E12   - Cayin C5. But finally I choose the Cayin C5 and theres were the magic begins. BANG it was amazing. This great Amp was helping the Fiio X3 driving these beefy Hifiman. With the boost turned on from my amp I could still enjoy a crystal clear quality and I couldn't believe the sound was coming out from this equipment and getting the best from these headphones. Finally I spend around 500 Euros but now I can say they were well spent

My source is a 2011 Macbook Pro-->Emotiva XDA-1-->Schiit Asgard-->HE-400
 
*Disclaimer* I have Jerpad 2.0 modded the headphones
 
The HE-400 does many things well, but the star of its presentation is the bass quality.  
It has very good slam for an open can, but its texturing is to die for! 
Cello sounds very realistic, with a roundness imparted by its bass extension.
 
In terms of the mids, male vocals have a very visceral, tactile quality about them, whereas female vocals seem to be missing a little bit.
 
The treble is rather hit or miss.  It seems to be fairly well extended, but it has a bit of tinny-nes and definitely sibilance that creep in from time to time.
I find electronic, rock, and vocal tracks to be the best for this, but then again I don't listen to many other things, so take this with a grain of salt.
 
To compare this with the HD800, which I have only heard twice in Bay Bloor Radio, the bass has better texture, but the mids are more "accurate" sounding on the HD800.
Of course, the soundstage/imaging on the HD800 trounces the HE-400, and the treble is far better extended on the HD800.
This is only from what I remember, and I believe the Sennheiser was hooked up to a Bryston amplifier.
 
All-in-all, I love the HE-400 for what it does best, just wish there was a bit more presence in the upper mids to make them a little flatter.

I have owned my HE-400 for over 3 years now. I have gone through a love hate relationship with them as they simply are not the jack of all trades headphone I was looking for. However, over the years I began to appreciate their outstanding qualities they do posses. These cans go incredibly good with trip hop, hip hop, instrumental and orchestra. Vocal based music is a hit or a miss. Males can end up sounding quite a bit deeper but sometimes missing that organic warmth due to the rise of the 1k region and scooped mids after which make vocals sound nasal. Same applies to women vocals, but that is caused by the peaky highs. Again this depends on the track and how it was mastered. Bright songs tend to be too peaky and the highs on this headphones do not pair well with that, warm mastered songs have no problems. However, movie soundtracks, movies themself, games, instrumentals and complex passages are fantastic. American music sounds fantastic too think of hip hop, rap or pop songs. Their imaging and soundstage are good for gaming too. These headphones have lightning fast transient response, and have a tremendous way of imaging the sound in this almost holographic fashion. They tend to still give me that surprise or waw moment even after all these years. They do sound better when around the 90db mark and not lower, but listen with care people. Also, make sure your room has no fridge or such in the background as any background sound messes with this headphone's clarity. They leak massive amount of sound so it's a headphone for private listening. All in all, these are definite keepers. They are so good for their price range that I decided to buy a second pair in case they become too rare over time. This headphone is a clear step above dynamic headphone offerings under 500$. Their achilles heel is that the stock frequency response is not for all tracks which is also why I will buy a HE-500 alongside these, comparisons will be made in the interest of time. If you are looking at Planar's look at the HE-6, HE-500 or these. The double sided magnet design give them a more organic and speaker like presentation that not even the newer planers from Hifiman can match.

 
As of September 2014, the HE-400 has been discontinued, and it's successor, the HE-400i is being sold in its place. So why publish, or even read, a review now? First, there are many used HE-400s in the market and are being considered for purchase. Second, many retailers still have new stock of the now heavily discounted HE-400, and these are the latest versions with no risk of future revisions. Third, based on 3 days of listening to the HE-400i, I've concluded that the new 'i' version is not an upgrade to the HE-400. It's a different sound signature. Asides from the considerable cost savings, I can see how someone could prefer the sound of the original HE-400 over the HE-400i.

Review set-up;
Source: PC  -> Teac UD-H01 USB DAC -> -or- FiiO X5->
-> Objective 2 Amplifier -> Hifiman HE-400 (Pleather Pads)

Hifiman HE-400

The Hifiman HE-400 is an open-back, over-the-ear headphone with an orthodynamic / planar magnetic driver. It's a break-through in the sense, in that Hifiman achieved it's relatively affordable pricing through advances made in automating the production of the traditionally handmade planar magnetic drivers. Most recent models with this type and size of driver are sold closer to the $900-1000 mark or higher when introduced (the prices come down of course). The HE-400s MSRP is $400, and (as of Sept. 2014) the fact that it's successor, the HE-400i (MSRP: $500) has hit the market, has a street price of significantly way below that.

With a rated sensitivity of 92.5 dB/mW at 35 Ohm impedance, it falls into the  category of high-efficiency planars - headphones with planar magnetic drivers that don't need a powerful desktop amplifier to sound their best. In comparison, the HE-500 and HE-6 models up the line have sensitivity ratings of 89 dB/mW and 83.5 dB/mW respectively. Since dB is a logarithmic unit, an 83.5 or 89 dB/mW sensitivity rating means a headphone will need a lot more power than one rated at 92.5 dB/mW to reach a given loudness level, despite what the  small difference in number would suggest. To reach the volume of a typical live concert (115 dB SPL),  the HE-400 will need ~177.93 milliwatts while the HE-500 and HE-6 will need ~398.34 and ~1413.29 milliwatts respectively. Big difference.

(Note: these numbers are approximate as there is some disparity between manufacturer spec sheet numbers and actual measurements.)

Because of this, high-efficiency planars are in a practically different league from their desktop bound siblings, as they can be used  in a portable rig.  Ideally,  a powerful portable rig, as it still needs a fair amount of power to reach really loud levels. While the popular FiiO X3 and X5 players using their internal amplifiers (which are quite powerful relative to other portable players) can drive the HE-400 to fairly loud levels on their respective high gain settings, it still doesn't sound as dynamic, most noticeably in terms of bass extension and impact, as when being driven by a separate portable amplifier. Think along the lines of the better portable amplifiers, such as the Objective 2 or FiiO E12. The sound impressions written here are based on the HE-400 being amplified by the Objective 2.

Sound Impressions

Have a look at the =3651&graphID[]=3241&graphID[]=353&scale=30]HE-400's frequency response curve, against the curves of the Hifiman HE-500 and Grado SR80i. Notice that there is a dip at the 2000-6000 hz frequencies, but then goes back up at around 7000 hz to a peak at 9000 hz. This is what gives the HE-400 it's somewhat unique sound signature. Vocals, guitar, piano - anything that falls between the 2000-6000 hz range is attenuated or sounds further away, with the details being masked by the other more prominent frequencies, while the peak at the 8-9 Khz range imparts some brightness to the resulting sound. Translated visually, its sound is like a dark rolling cloud with rich tonal variations from black to middle shades of grey, punctuated with bright (but not blinding) streaks of lightning which can actually be very satisfying, depending on the type of music being listened to.

Hifiman themselves have stated that it is tuned for a more 'American' (I take it this means emphasized bass) sound signature, as opposed to the more polite and neutral 'British' sound of the HE-500 next up in the line. The HE-400's bass does have a satisfying amount of slam while still retaining texture and clarity - its massive planar magnetic drivers characteristically being able to render and stop the sound very precisely (transient response). This, combined with the 8-9 Khz treble peak, gives the HE-400 sound signature a satisfying sense of dynamic contrast with a combination of hard-hitting bass on the low-end and some treble 'air' on the high-end, albeit with (or in a sense, because of) a recessed upper mid-range and lower treble.

If you like live recordings of rock bands like Soundgarden, Guns N' Roses or Evanescence, with the thunderous and deep rumbling combinations of drums and guitar bass, and like to listen loud but without any shrillness in the treble from shrieking/shouty vocals, snare drums, cymbals, or lead guitars, you will appreciate the HE-400. In comparison, the Grado SR80i, which is also considered great for rock music, would start sounding harsh or piercing due to emphasized treble frequencies, and have  less bass impact at the same loudness level. Between them, it comes down to a choice between the HE-400's bass slam with good transient response vs. the SR80i's mid-range presence and detailed treble emphasis.

On the other hand, when listening to some acoustic or 'unplugged' recordings which have so much vocal or instrumental richness and subtlety in the 2000-6000 Khz range,  I would prefer either the STAX SR-207 or, to a lesser degree, the Grado SR80i, which will bring those elements forward. While the HE-400 by no means sounds bad with this type of music (it's still better than most 'default' headphones), I would prefer a more intimate vocal presentation - it's a subtle difference that can nonetheless change the way a song is appreciated.

I emphasized the word 'some' earlier because it really depends on how the music was mastered. I have high-resolution 24-bit/96Khz recordings of acoustic jazz with female vocals purchased from E-Onkyo Music, which sound impressively life-like with this headphone. Granted, these are audiophile recordings meant for playback in more technically capable systems, and it goes to show that the way the music is recorded and mastered plays just as significant a role as its genre. For typical recordings of electronic dance music and live rock (not acoustic) sets, the HE-400 generally works well.

 

Conclusion

Sometimes it pays to be late in the game.  Due to a combination of technological developments and price drops due to newer models being introduced, the Hifiman HE-400  scores very high in the price/performance scale. This assumes that the HE-400’s sound signature works with the listener’s music and preferences.  The newer model HE-400i has a completely different sound signature that does not build on the original’s strengths, so calling it a direct upgrade would be somewhat misleading.  I would consider the HE-400i as more of a sidegrade – a different headphone with a sound signature that appeals  for different reasons.

While the older HE-400s sound signature may not be ideal for all musical genres or recordings, when the stars of sound signature, music , and listener preference  line-up, it’s brilliant.  Combined with the Objective 2, it is still very much worth considering for high-end sound, in a  transportable package

Setup 1: Win7 PC -> USB -> Modi -> PYST -> Magni
Setup 2: Win7 PC -> USB -> E10k
 
Summary
 
Disclaimer: this is my first review on Head-Fi and I fully declare that I know (nearly) nothing.  Please be kind.
 
Based on the reviews I read here and elsewhere, I chose to go with the HE400's for my quiet, at-home setup.  My primary listening material is electronic house, jazz, and swing, so I figured I'd go with a headphone that everyone described as "fun" and "interesting".  But as soon as I plugged them in I knew something was wrong.  The detail was phenomenal, the bass lovely and linear (and gets notably better with burn-in), and treble surprisingly clear.  But most men's voices, the low notes in women's voices, some cymbals, violas, and french horns all sounded like they were behind a velvet curtain.  On some recordings these headphones are truly spectacular, but almost half the time I found myself recoiling at the bizarre frequency response hole with which I was presented.  After some 20 hours of testing and listening I have decided that $300 headphones shouldn't make me go "ew", and have decided to return them and try some much-flatter HD-600's instead.
 
Physical Attributes
 
The packaging is simple but effective and got the 'phones to me without any kind of damage.
 
Instead of a rigid carrying case, like what I got with my Senny HD 380 Pro's, HiFiMan provides a simple velvet bag.  While this might be good for some gentle kinds of transport, there's no way I'd put these in my backpack or anything.
 
Although bright blue in some photos, in real-life mine had a nice, dark blue colour.  The cans themselves look quite nice, but the headband and its attachments are bargain-basement.
 
Comfort
 
Out of the box the HE400’s definitely have death grip.  Fortunately, the headband is somewhat bendable, so it’s quite easy to reshape it to lower clamp force.  For that matter, if you had some kind of head deformity you could probably bend it to work around that, too!
 
The ear cups are nice and deep and didn’t touch my sticky-outy ears at all.  My HE400’s came with both the pleather and velour pads, and I found that the velours were about 7mm thicker than the pleathers.  The cups themselves are very large.  While this might be good for some people, they were so big on my face that they touched my jawbone and forced my mouth open slightly!  When I think of listening fatigue I don’t often think of a sore jaw, but there you go.
 
While I didn’t find the cable to be hard to manage, one strange consequence of its rigidity was that it pulled my head down.  I found that the cable had such a hard time bending around things (like the arm of my listening chair) that it would pull my head towards where the cable was coiled, on the floor in my case.
 
Despite my whinging, the comfort isn’t that bad, say 7/10, but they’re not a forge-that-you-even-have-them-on headphone like my HD 380’s.  
 
Amplification
 
While it could be that there ‘phones weren’t burned in at all, I did find that my E10k DAC/Amp didn’t bring out the bass in the HE400.  Once I got them home and plugged them in to my Magni I noticed that bass had much more presence, without ever being boomy or overpowering.  Bass is noticeably absent without amplification, though, so don’t listen to the marketing and think that you’ll be fine driving these with an iPod.
 
Sound
 
The HE400’s do most things very well.  I put on Sting’s The Last Ship and couldn’t believe how good it sounded.  Sting sounded perfectly positioned in the sound stage, and the acoustical accompaniments were clear and detailed.  I sat there and listened to the whole album and thought I had found acoustic bliss.  Despite what most say, I found that a lot of classical music, especially Vivaldi, sounded great on these headphones, too.
 
But when I put on nearly anything else I thought of velvet, and too much of it.  The female vocalist from The Moleskins, for example, sounded like she was singing from 5 metres behind her band.  A viola, cello, or french horn soloist sound like they’re playing in a velvet-lined box, and some cymbals sound as though they’re not even on the same sound stage!
 
So what is causing this?  The 2,000 to 6,000 Hz frequency response hole.  If you bring up the FR for the HE400 on HeadRoom you’ll see it quite clearly.  In retrospect I should have known better, but I was expecting it to manifest differently.  Material that is recorded flat presents the hole quite clearly.  It’s only material that is recorded with those frequencies over-amped that sounds truly great to me on these headphones.  And that’s what was going on with the Sting and Vivaldi recordings that I liked.  On my Shure E2 IEMs (my favourite reference monitors to date) Sting sounds way too forward and Vivaldi harsh.  The FR hole in the HE400’s was simply flattening those out for me.  Unfortunately for the HE400’s, most recordings are between flat and laid-back, and the more laid-back the worse the recording sounds on them.
 
Conclusion
 
The HE400’s are great headphones for some recordings.  They have a velvety-smooth signature, great detail, and amazing channel separation.  But when I add up the frequency response hole and the comfort issues I experienced I have decided to return these headphones and try something else.
 
Would I buy these again?  Probably not.  If I were to go for some more orthodynamics I’d go with something with flatter tuning.  Still, this was a fun experiment and I get to exercise Amazon’s return policy, something I don’t do often.
 
Arriving next week: Sennheiser HD600’s.  At least on a graph, they seem much more attuned to my tastes.

Full video review below
 

Engineer's dream, but lacks any comfort.  3 month owner.  
 
Pros:
Sound Quality excellent -
      Lows - shame on you if you don't already know these are bassy.
      Mids - average sound quality.  limited range, but great detail.
      High - slightly 'punchy'/undetailed and a bit bright, but still great.
No sibilance - you get the point.
Aesthetics - easy on the eyes, great look.
 
Cons:
Weight - padding on headband wears out in a month.  It will hurt your head if you don't bend the medal headband to size accordingly.  It got to the point where I had to make a custom pad for the top of my head.
Ear cushions - synthetic leather can get quite hot.  I tend to sweat with any form of leather, so aftermarket ear cushions were a must.
Cable connection - this is the biggest design flaw of the headphone.  I had my 400's RMA's because the connection point between the headphone and cable broke off.  The actual cable sticks out of the bottom of the ear piece and rubs against your shoulders which is annoying for some.
 
Bottom Line: I researched for dozens of hours on different headphones and consistently heard these were the best in their class. Basically, if you are thinking about buying for sound and would be willing to sacrifice comfort then welcome to your new headphones.  If you have the money then I would recommend buying the 560's as after testing had much better mids.

These are warm but detailed. They are fun to listen to, like the other Hifiman products (I have a couple).
 
I enjoyed using them and got a HE560.
 
Will give them as a gift to somebody. They are nice open headphones for the price. I can expect they will enjoy them.
 
Still working after a year of use.