HiFiMAN HE-400

When I originally got into this hobby some 2 years ago, my first run of purchases included Sennheiser HD650's and Denon D5000.... I also had a couple beaters like Klipsch Image Ones and Koss Porta Pros..... upon purchasing my first bonafied 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 chapter and enjoy some music.

I focused a good amount of energy and resources from there 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 a "How It's Made" at the AKG factory in Austria....

OH!... Headphones!.... I LIKE THOSE!

Since Steinhart are setting their restock date in August... lets see what's new in the headphone world.

And so the bug bit again.... but this time reading through forums and websites brought forth many mentions of a new player in the game... Hifiman and its Chinese visionary leader Dr. Fang Bian. 

I originally planned on buying one of the early models (HE-4, HE-5 second hand and was even looking at drumming up the cash to buy the HE500 when I caught word that a new lower priced planar magnetic model had hit the streets.... the HE400.

I perused the Headfonia article which gave it a restrained thumbs up as well as the effusive gushing review by Steve Guttenberg and decided to pull the trigger.

And so after purchasing the headphones on Amazon for $399 they arrived at my doorstep about 10 days later with obvious signs of having shipped direct from China.

When I opened the box I was a bit 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... A sticker on the exterior of the box seemed to imply that this was some demo model... yet I paid full price.... WTF!

Needless to say the Hifiman HE400 and me did not have a very good introduction... no love at first sight here.... I was suspicious of this johnny come lately and probably had mixed feelings about this headphone until the point where I plugged it in and pushed play. And that is where the criticisms ended. 

Up until this point all of my headphones were on the warm and bass heavy side.... Denon D5K's, HD650's, Porta Pro's and Klipsch Image Ones that I once heard described as "bass fart cannons".... so my predisposition of what a good headphone sounded like was a bit tilted to one side.... But plugging in the HE400's I was taken back initially.... They were clear.... crisp.... the bass was there but certainly not up with the D5ks or 650s... but as I listened and listened I had that "AHA!" moment.... These things sound good... very good! very very good!

The HE400 sound is not lush or warm or thick.... It is smooth but hangs its hat on clarity and providing a balanced perspective of the music. Some have called it a bass heavy can but I don't see that. 

Comparing it to the HD650 its sound is much more neutral (oh the word of death!) but it doesn't lack of musicality.... What one does discover listening to this headphone is that the slightly more forward and engaging mid range gives it a very "LIVE" presentation.

Shortly thereafter I purchased the planar magnetic darling of Headfi Audeze LCD2 and was originally assuming that the HIFIMan can would lose its luster after the LCD2 arrived but this was not so....

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 some slow 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 and  forwardness to the mid range that gives it a more realistic, live sound.

I saw the LCD2 as sounding like home listening while the HE400 was like being at a show.... That ever so slight tipped up mid range made the HE400 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 and it is rarely mentioned on this site, is that while the LCD2 can give you a ridiculously well resolved low frequency that mines the depths of a song to reproduce it with perfect symmetry and resolution, the HE400 actually provides a bit more punch and impact despite being a bit less confident in its resolve. 

The HE400 is prone to get a little fuzzy where the LCD2 provides crystal clear realism.... but it makes up for it with 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 euphonic and lush and warm like the HD650... but in terms of accuracy vs. impact it has found an amazingly intoxicating balance.... The LCD2 seemed too focused on technical skill and speed and this 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 it is an amazing performer in the right setting and is a decent all rounder.

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 ears dangling on the bottom of them when not connected to the cable but... this should only bother the most aesthetically anal 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 only $400 can that I'd argue keeps pace is the Sennheiser HD6XX team.

Buy with confidence.... The HE400 is worth every penny. You will not regret it.  

HiFiMAN HE400

By now I think most of us are familiar with the history behind the HiFiMAN HE-series headphones. What started with a single model has grown into a full lineup, with prices ranging from $1299 for the flagship HE-6 to just $249 for the entry-level HE-300. Worth noting is that the HE-300 stands apart from the rest by using a “traditional” dynamic driver. Every other model in the HE-series is based on planar magnetic driver technology.

The entry level position among the planar models is held by the HE-400. It is the most recent HiFiMAN headphone released and sells for $399, putting it in competition with some more established designs such as the Sennheiser HD600/650, AKG K701, and Denon D2000. As the only planar model available in this price range, I was curious how the HE-400 would measure up.

Those who follow my ramblings here know that I have a newborn baby in the house. Accompanying the birth of that little guy was a major purge of my open headphones; the logic being that I wouldn’t be getting much use out of them. So I sold my Sennheiser HD600, HD650, and HD800, my Grado PS1000 and RS1, and my Beyer DT880 and DT990. I also passed on buying the Audeze LCD-2 and HiFiMAN HE-500, which I have borrowed from friends multiple times and really wanted to own. Yet here I am with a new open headphone – why? The answer is simple: it’s one thing to have a $900 or $1,000 headphone sitting around getting little use. It’s quite another matter with a $399 model. I figured I would start small in the HiFiMAN lineup and make my way up the ladder when the time is right. Since then, the HE-500 has dropped to $699, but the point remains the same.

DESIGN

One would think that HiFiMAN must have cut some major corners with the HE-400 to allow pricing it at nearly half what the HE-500 sells for. But one would be wrong in that assumption. HiFiMAN claims the key to the low price is the use of automated manufacturing techniques. Apparently their planar magnetic designs are mature enough by this point to allow some level of hands-off construction. If anyone has ever seen the episode of “How It’s Made” showing the AKG factory building K702 headphones, you’ll note how automation makes the process many times faster and more efficient than it otherwise would be. There is still an element of human involvement but it is reduced in many key areas.

Think of a handmade… well, anything really. Whatever it is you picture, it’s going to be labor intensive to build. It’s also going to be expensive compared to an assembly line type operation. And it’s going to be more prone to have variability and likely a higher rate of flaws. Until now, it seems that all HE-series headphones were hand crafted. That sounds impressive but in reality there have always been issues with the method – think Audeze LCD-2 and LCD-3 sounding different from one example to the next. Think the initial run of the Grado PS1000 and the often disappointing silver finish. With the HE-400, HiFiMAN has automated the process of producing the driver, and I suspect at some point soon they will have more of the process automated, similar to AKG. The bottom line here is that the HE-400 may have otherwise been slapped with a $500 or $600 price tag if this new development process had not been achieved. So don’t think of it merely as a “budget” headphone with all the negative connotations that go along with that thought. Rather, think of it as an “optimized” design which allows the price to stay relatively modest.

In terms of appearance the HE-400 is very similar to its HE-siblings. The key difference is the blue paintjob, which I actually find more attractive than the usual dark color of the other models. Other than that we get the same leather headband, the same frame assembly, the same detachable cabling system, and the same earpads. But there are a few significant differences worth noting.

First, and probably most important, are the drivers themselves. They have smaller magnets and appear less complicated compared to the older models. While the HE-500 driver assembly looks like a fancy cheese grater, the HE-400 uses less complex perforations and a good amount of plastic. There’s also the earpad attachment system which is far better than the older “tab” system. It still isn’t perfect but I was able to swap pads several times without wanting to throw the headphones out the window in frustration. I consider that improvement. I believe all of the HE-series models are now using this new system. Then there’s the packaging and cable differences which I’ll discuss a bit later.

Here are the pertinent specs for the HE-400:

·       Efficiency: 92.5 dB/mW

·       Impedance: 38 Ohm

·       Planar Magnetic driver (orthodynamic)

·       Frequency response: 20 Hz to 35 kHz

·        Weight: 440 g

In comparison, the HE-500 is 89dB and 502g. That means the HE-400 is lighter and easier to drive. Supposedly one could even run the HE-400 straight from an iPod, though I can’t imagine a scenario where I would actually want to do that. This is certainly not a portable headphone. Still, the prior HE-series models were known to bring many headphone amps to their knees, so the improved efficiency is very welcome, as is the reduced weight.

BUILD QUALITY

Like the prior models, the HE-400 is nice but not perfect. It doesn’t have the same level of sophistication and “tightness” that something like a Sennheiser or Audio Technica would have. But overall it is acceptable for the price. The blue finish is attractive, and there is a good mix of leather, metal, and plastic. The new pleather earpads feel decent as far as pleather goes. I’m not usually much of a fan and I would have preferred the velours instead, but I’ve seen far worse. The new pad attachment system does allow the pads to “spin” more freely than I’d like. It’s the only area that feels to me like it isn’t of very high quality. Yet the pads never fall off and are fairly easy to swap, so maybe I shouldn’t complain. 

PACKAGE

Prior HE models came in a nice looking storage case. In contrast, the HE-400 ships in a fairly basic plastic package as if it was a $50 headphone. As much as I miss the “wow factor” of the fancy box, I’m actually glad it was omitted here - unnecessary extras are just what you don’t need when trying to keep prices low. HiFiMAN does throw in a storage pouch which I’ve never once used; I guess it’s better than nothing and some people might have use for it. HiFiMAN sells a nice travel case for $29 if anyone desired such a thing. My HE-400 lives on a headphone stand so I’m pleased that I wasn’t forced to pay for a storage case that I’ll never use.

Prior models included a single spare earpad. I always thought that was strange – why not a pair? The HE-400 solves that strangeness by no longer including anything. And that’s fine by me. Additional sets in velour can be had for just $10 a pair.

The included cable is 10 feet long, terminates in a 1/8” plug, and is fairly thick and unwieldy. For me, this was the biggest letdown of the whole experience. I recall not being a big fan of the HE-500 cable, so I knew this one would probably be bad, but over time I came to really dislike it. It was an easy fix due to the plethora of aftermarket cable options on the market. Some people may not be as easily annoyed as I am, and may find the stock cable totally acceptable.

EQUIPMENT

This is the equipment I used for my evaluation of the HE-400:

Source: JF Digital HDM-03S music server, Squeezebox Touch, Marantz SA-1

DAC: Violectric V800, Anedio D2, Yulong Sabre D18, Matrix Quattro DAC, Kao Audio UD2C-HP, Grant Fidelity TubeDAC-11

AMP: Analog Design Labs Svetlana 2, Violectric V200, Yulong Sabre A18, Matrix Quattro Amp, Lake People G109P, Apex Butte, Audinst AMP-HP

Cables: As I’ll discuss later, I didn’t care for the stock HE-400 cable. So I replaced it with a CablePro Earcandy for single ended use and a Toxic Cables Hybrid for balanced operation.

Earpads: I swapped out the stock pads for a set of Lawton modified Denon D7000 pads. I’ll explain later.

Power was handled by a CablePro Revelation conditioner and CablePro Reverie AC cables. Interconnects were Signal Cable Analog Two for RCA and Paillics Silver Net for XLR. The HE-400 was burned in for well over 100 hours prior to doing any critical listening.

LISTENING

I have to preface this by telling my story about the pads. The stock pads are actually pretty nice - I was worried that I would have major isses with overheating, but that ended up not being the case. No, my issue was on the left side of my head apparently being a little lumpy. Behind my left ear, the stock pad would leave a tiny gap smaller than my pinkie finger. No amount of fiddling with the headband or cup angle seemed to remedy this. I've never had this issue with any of the dozens of headphones I've used, including the HE-500 with velour pads. I can’t fault the HE-400 but rather my own uneven skull. In any case, the gap caused a small but audible difference in sound from left side to right.

Obviously I couldn't eveluate the HE-400 without a proper seal. I borrowed an HE-500 from a friend but it used the older mounting system, so the velour pads were of no use. I was considering ordering a set (they are very reasonably priced) when I had an idea - why not try a few other pads that I have around the house? The very first set I found when I went digging in the drawer was from a Denon D7000. It had been modified by Lawton Audio when I sent my D7000 in for upgrades. When Lawton returned my Denons in LA7000 form, I never actually used the pads, opting instead for the J-Money V3 pads. So these Lawton pads were just waiting for a new home. For those unfamiliar, Lawton stuffs the pads with extra Poly Fil type material, especially to the rear area, which makes them look somewhat like an Audeze LCD-2 pad. It makes a great seal with my (apparently oddly shaped) head, and helps position the drivers at an angle to theoretically give a more speaker-like presentation. All of the impressions that follow were obtained with the Lawton pads in place. Since I couldn't get a good seal with the stock pads, no comparisons are possible. That might invalidate some of my impressions but there’s nothing I can do about it.

The sound from the HE-400 was immediately appealing to me. I heard the typical "planar" presentation which I categorize as having a sort of effortless sound to it, with excellent deep bass extension. I don't know how better to describe it, but it’s something that the LCD-2, Thunderpants, and HiFiMAN models all have in common, despite all sounding very different from one another. There's just an ease to the presentation that dynamic headphones can't quite match. I'm not saying planars are always superior, but this is one of their strengths.

Bass on the HE-400 is very nicely done. It isn't huge, but has enough of a solid impact and presence to be satisfying for all but the most extreme basshead listeners. Where similarly priced dynamic headphones from Sennheiser, AKG, and Beyerdynamic all have rolled off frequency response in the sub-40Hz range, the HE-400 (like most planar models) stays almost completely linear down to 25Hz or so, with a very mild drop below that. To my ears this ends up sounding more convincing; as if more air is being displaced. And maybe it actually is. The bass presentation is very close to that of the HE-500, lacking only a small amount of texture and refinement in direct comparison. On its own though it is some of the best low frequency reproduction I’ve heard from a non-flagship headphone.

Mids on the HE-400 are somewhat forward. This gives it a more exciting sound than the more neutral HE-500. There's an added "bite" to things like trumpets and violins, making for a very engaging listen. The mids have a nice smoothness to them though, meaning they aren't just run of mill, average quality stuff being boosted to sound more exciting. They really do have enough clarity and focus to pull off this little trick. Upper mids are somewhat subdued, which generally makes for a smooth presentation though it can occasionally take away some realism in the form of a lack of airiness or trailing edge. This was mostly noticeable with really well recorded tracks – on lesser material it could actually help hide some of the harshness from poor mastering. So it ends up being a give and take.

As with many headphones, the highs of the HE-400 are the one area where it isn't perfect. It isn't terrible either, but this is where I heard the biggest divide between the HE-400 and HE-500. The 400 has a bit of darkness to it but also has some brightness. "Dark and bright at the same time? How can that be?" Take a look at the Frequency Response chart as measured by Tyll at InnerFidelity. Notice the “droop” starting at roughly 1.5kHz which doesn't pick up until around 7kHz. From there it actually gets somewhat bright, and that's exactly how I hear it. Brass and woodwinds, while seeming fairly cool and dark overall, also have some "zing" up top peaking at 9kHz or so. This can sometimes come across as a bit brittle or harsh. Other times it is inoffensive and actually brings out some extra perceived detail. It works more often than not, but it must be mentioned because certain people are more sensitive to these types of peaks. I also need to point out how hard it was for me to wrap my brain around this presentation. With female vocals for example, you hear something of a darker presentation with less air or breathiness, which would normally be smooth all the way around. But then you get this peak which tends to accent certain consonant sounds, not quite sibilant but borderline.

Once Tyll got his measurements posted it started making more sense, though I do think my pad swap has helped the problem somewhat. I know people who use the velour pads and they report a subjective improvement as well, so that's something I definitely think is worth exploring since it costs so little.

I was surprised that the HE-400 was able to pull off a reasonably large and very well defined soundstage despite being on the darker side. Planar models tend to not have the most spacious presentation anyway, and the same goes for darker headphones in general. So I figured the HE-400 wouldn't have much going on to brag about in this area. Perhaps my angled pads are doing a lot to help, but I really do find these to be nice and open sounding, with good definition of the musical space. Imaging is accurate and there is some really nice layering going on. It might not be up to par with the HE-6 or HE-500, but it is definitely near the top of the pack in the "mid-fi" range where HiFiMAN has positioned this model. The K701 and variants might be more spacious but it comes at the cost of being somwhat artifical.

AMPING

The HE-400 is supposedly the planar for the common man. It doesn't require heavy amplification, so one could reasonably use it from a fairly low powered amp, or even straight from a DAP. That's the theory anyway. In practice I found that to be only partially true.

Yes, my iPad and Sansa Clip can drive the HE400 to reasonably loud levels, and the resulting sound is certainly listenable. But I don't enjoy it nearly as much as I do when adding even a basic amp like my portable Audinst AMP-HP. Specifically, the bass presentation is nowhere near as satisfying until a separate amp is involved. And the highs are much more prone to offend with that “edginess” I mentioned. The only exception to this amp required rule might be some of the "premium" portable units such as the iBasso DX100 or HiFiMAN's own HM series. I did try my RoCoo D Power Edition and the result was reasonably good – better than my iPad, but still not great. Ultimately I would never use this as a portable headphone anyway so I don't mind the amp requirement.

As far as which amps work best, it becomes a question of sound signature preferences. All amps have their own unique presentation, and while the differences are not always huge, you want to pick one that best fits your predilection. I found that I enjoyed the HE-400 with all of my desktop amps, but some were better than others. I don't care how sensitive they are, planar headphones seem to always respond to power. For that reason the powerful Violectric V200 and its cousin the Lake People G109P did a fantastic job. The V200 had a little more clarity on the top end but for the most part the cheaper G109P was able to keep up.  I also liked the Apex Butte and the Analog Design Labs Svetlana 2 for their exceptional midrange presentation. The Matrix Quattro amp in balanced mode offered an enjoyably smooth, refined presentation for a low price. But I think my favorite pairing is with the new Yulong Sabre A18 amp in balanced mode. This is a Class A, fully discrete, differential design that just mates perfectly with the HE-400. It delivers just under 2 full watts per channel to this particular headphone, bringing it close to the V200 in terms of current delivery. But it has an exceptionally expansive soundstage that sets it apart from the Violectric model. It isn't always better with every headphone, but the HE-400 seems to be a perfect match. Single ended mode was good too, but not quite up to the same level, and in that situation the V200 regained the lead. For anyone interested in balanced operation, I highly recommend the A18/HE-400 pairing.

With a seemingly dark headphone like this you don't want to obfuscate any of the top end presentation by using a darker amp. Yet the sometimes peaky highs also don't need any extra attention either. So keep in mind when planning an HE-400 based system: a generally neutral amp is desirable over one with a strong coloration of any type.

COMPARISONS

I have owned most of the similarly priced headphones that would be considered competition to the HE-400. Unfortunately I no longer have any of them on hand for direct comparison. But I'm familiar enough with them to make some generalizations.

The AKG K701, and its brethren in various colors, are very different from the HE-400. Almost complete opposites - they have significantly less low frequency resolution, and as a result give the impression of significantly more energy in the upper mids. Personally I would choose the HE-400 every time, except perhaps in the categories of comfort and soundstage size.

The Sennheiser HD650 is still a killer headphone in my opinion. I think it offers a more even, linear presentation from top to bottom, while the HE-400 is far more exciting and dynamic. These two would actually complement each other quite nicely if a person wanted to own two headphone for two different takes on their music.

The Beyerdynamic line of DT770/880/990 is in process of being replaced by the new T70/80/90 models. But not all of those are released yet, and way more people have experience with the DT series. So this is still a fair comparison. The HE-400 strikes me as being somewhere in between the 880 and 990, but superior to either. It has less bass quantity than the 990, but to my ears it does lows in a much more convincing manner. Sub-bass extension is superior to the point where it just makes the 990 sound bad in comparison... and keep in mind that I actually do like the 990. Mids are more forward than either Beyer model, which is a welcome improvement in my opinion. Highs reminds me more of the 990 but are not an exact match - I hear the HE-400 as being less grainy and having a more natural flow; even though they do both get harsh on some tracks, the 990 is clearly the bigger offender.

CABLES

I mentioned prior that I disliked the length and thickness of the stock cable. So I picked up two different aftermarket cables to try out. Both of them are miles ahead of the stock cable ergonomically, and both happen to look much better as well.

The first is the CablePro Earcandy which is currently on sale for $109 (regularly $129) for a 10 foot length. Construction is described as finely stranded 22 gauge OFC conductors, with a low-loss polyethylene dielectric and an OFC braided shield to block noise. Mine has a 1/4" Neutrik plug for single ended operation though other options do exist.  This is a very flexible cable with a low key, classy look to it that exudes quality while still remaining understated. It reminds me of the Cardas Sennheiser upgrade cables, but obviously priced way lower. I have to say I’m exceedingly pleased with the service I received from the company - CablePro sells all kinds of products (several of which I own) and they are extremely pleasant and helpful.

The other cable I got is from Toxic Cables. Based in the UK, their Hybrid cable uses a combination of cryo treated OCC copper and cryo treated OCC silver plated copper. I got mine with balanced termination though again, other choices exist. As of today's exchange rate the price translates to $134 for a 6 footlength. This cable looks like it should cost significantly more than it does – if the color was different it would looks a lot like the older (and rather expensive) Lawton Audio Jena Labs recable jobs. The best part is that it’s surprisingly flexible and easy to manage. I refuse to deal with an unwieldy cable no matter how nice it might look, so this aspect is critical for me. Toxic Cables is also a great company to deal with, and is actually an authorized HiFiMAN distributor as well - so headphone and cables could all be ordered together if one was interested. 

With a new headphone to figure out, a newborn baby in the house, and plenty of other reviews on deck, I don't have time to get into a cable debate here. I did let a friend who is a certified cable nut (and has way more free time than I do) borrow both cables, and he loved them. He normally uses Moon Audio Silver Dragon V3 cables for his HE-500 as well as his original HE-5. In his opinion, both the CablePro and Toxic Cables products were just as good as the more expensive Moon option, and possibly better. He said he liked the Earcandy more with his Cary Xciter amp driving the HE-5, and the Hybrid more with his HE-500 powered by the Red Wine Audio Audeze Edition balanced amp/DAC unit. Something about "synergy". Neither of those amps are high up on my list of favorites, so obviously he and I have different tastes. Yet we both enjoy these cables. I intend to keep them both - one will stay with the HE-400 and the other will pair with some future flagship HiFiMAN model that I'll eventually pick up.

CONCLUSION

HiFiMAN has done an excellent job of tuning the HE-400 to have big, bold sonics with any type of music you throw at them. The low frequency capabilites are very impressive, sounding very close to the much more expensive HiFiMAN models. And the mids are wonderfully engaging - nobody would ever call this a boring sound signature. The only area of concern is the highs; most of the time it is smooth, slightly dark, and generally inoffensive. Every once in a while it becomes just grating enough to remind the listener that this is in fact still a "budget" model. 

It sounds like I'm being hard on the HE-400 with my description of the highs. I don't mean to be picky and I don't want to overstate the problem. These really are excellent sounding headphones in the sub-$500 price bracket - a bracket where all entries will be flawed in one way or another. To some extent you have to pick the flaw which you find least offensive and go with that one.

I will say that these are my current favorites in the sub-$500 range. The HD650 is still an excellent all purpose model that could be a suitable counterpart for the HE-400, but if I had to choose just one I'd go with the HE-400 first. The Grado RS-2 might be more exciting for a very limited selection of music, but with everything else the HE-400 leaves it in the dust. Believe it or not, I could totally see the HE-400 being preferred over the HE-500 for some listeners. I think HiFiMAN has done a great job with this release and I can easily recommend them to anyone looking to purchase a good sounding headphone that isn't astronomically priced.

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.

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 stuff, pop, dubstep & electronic. I can only comment on my own system because i've never owned anything else. The sound is very balanced, very full, bass is tight, mids are really nice, gives guitar and vocals that extra richness, highs aren't harsh and there's not much sibilance. 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. You can really see where Dr. Hifiman has saved up on, 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. Comfort is one of the cons of this otherwise, really great sounding headphone, so take this into consideration.

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 noticable 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, more realistic imaging, and refinement in build and comfort. 

Synergy is excellent, the Burson Soloist suits the HE-400's sound signature and the Musical Fidelity Dac improves sound and 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.

Build Quality / Design: Metal forks and a nice dark blue finish. The logo paint fades easily, so do not touch it.  Pictures you see online don't do these much justice, trust me, they look much better in person. The headband is lacking a bit of padding, but I do not find it uncomfortable at all. These are pretty heavy, but the weight is distributed pretty evenly for me and are comfortable, just not so much as the HD 650 or HD 598. Stock pleather pads cause my ears to sweat after a bit, but velour pads for a mere $10 fix this easily. 

Bass: I have to admit, I was a bit underwhelmed by the bass produced by these, especially after hearing about how well orthodynamic headphones do bass. They provide an ample amount for Hip-Hop & Dubstep but impact isn't very low or too high. I was never "wowed" by the bass. It kept its place and never became intrusive unless I equalized them to death. More then enough bass for Jazz and easy listening though. Bass extends low & rolls off after about 30hz, but it just doesn't have the impact I crave unless I EQ these, and the HE-400 can handle the bass being equalized to ridiculously extreme levels. 

Midrange: The upper midrange is a bit laid back, but put a pair of velour pads & it becomes more evened out. Vocals feel a little back on some songs, I always thought these were a bit V-Shaped. 

Treble: The treble is bright and was almost unbearable the first time I heard them. It has now settled down quite nicely but I would say the treble is still bright. I notice sibilance in some songs as a result of this. I also find the bright treble fatiguing, it was OK at lower volumes but I couldn't stand it at higher volumes.

Sound-stage/Imaging: Moderate size, but the cheaper Q701 & HD 598 had a larger sound-stage. Quality wise, the HE-400 wins. The combination of air, energetic treble, and great layering was a much better experience as a whole, despite it's smaller size. I can easily follow and pinpoint an instrument or sound effect, while I would get lost trying to find them on the HD 598 & Q701.

Amping, Final thoughts: Yes, you can drive these with your laptop, phone, or iPod. The HE-400 was loud and portable sources could handle them. However, sound improves with a dedicated amp. I noticed slightly stronger bass, improved detail, and more sense of air. I really feel that these are a great value because of how well they handle being plugged into multiple sources. They sound great out of my iPod, Phone, 30 year old A/V receiever, and PSP & scale up with my amp nicely. The HE-400 handles every genre I throw at these, ranging from light jazz to heavy metal and can please a wide variety of music genres.

Some songs I have tested. All tests were with velours, Rolls RA53b amp, and FLAC or 320kb MP3's.

Tonight The World Dies, Avenged Sevenfold, Rock

Vocals have sibilance, but sound very realistic. Cymbals and drums crash with authority, perfect amount of bass. 

The Quiet Room, L'Orange, Electronic

Large amount of air & great detail. This is a lo-fi track trying to replicate the sound of vinyl, you can hear the smallest details like the scratching of the needle on the vinyl. Easy to follow the voices, piano, and everything in the song.

Everyday My Birthday, J Stalin, Rap

Bass is handled well and extends fully. However it does not "wow" you. It keeps it's place and never invades the rest of the sound spectrum, even though most people who listen to rap would rather have it be more pronounced. Good Imaging makes it easy to find and pinpoint where the rapper is, gunshots in the background, piano in the background, etc. Hi-Hats in the beat are played with authority because of the bright treble. No sibilance at all.

Execution, Andy Stott, Electronic

This song has very low bass. Headphones and even full size sub-woofers have trouble playing this. The HE-400 extended all the way down and was able to play the low bass (Under 40hz). The ambiance of the song surrounded my whole head. 

L.A. Noire Theme 9th Minor Extended, Andrew Hale, Jazz

Nice bass that never invades the rest of the sound. Soundstage and imaging is great, you can tell where the violins are, the Sax, piano, etc. All the instruments are rendered nicely and sound realistic. Treble was a bit too bright on some parts of the song, but was never a huge issue.

E Extended Mix, Drunkenmunkey, Techno

Drums and Hi-Hats rendered with authority, strong thumping bass with great speed that was able to keep up.

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