Yes, you read that right. HiFiMAN, in their continuing quest to rule the headphone universe has done something rather extraordinary. They have brought to market a real-deal planar magnetic, open back headphones at a very affordable price point.

The HE400S is something that would have been completely unheard of but a mere two years ago. Further still, these aren’t some existing pair of HiFiMAN drivers, nicked from another model, placed in a low-budget housing and pushed out the door to shore up a missing SKU. The HE400S are completely new, designed from the ground up, to properly win over new customers who otherwise wouldn’t have been able to afford planar headphones previously.

HiFiMAN HE400S Planar Magnetic Headphone


HiFiMAN HE400S Planar Magnetic Headphones

  • Lush, addictive soundstage
  • Warm, inviting vocals and plenty of bass, but not too much
  • Very light and comfortable to wear for extended periods
  • Solid build quality
  • Very efficient and easy to drive – they sounded great with my iPhone
  • Did I mention, they’re only $299?

While I don’t claim to be an authority on every pair of headphones out on the market, it’s been my experience that it’s easier to find a good sounding, expensive pair of headphones than it is to find a good sounding, affordable pair. Many a time in my life, I’ve found myself with a limited amount of financial resources that condemns me to choose from a sea of mediocre sounding entry-level headphones. Don’t get me wrong, I’ve occasionally been burned by some of the pricier stuff as well, but that is a decidedly rarer occurrence as spending more money usually causes me to spend more time on the research end of a potential purchase.


Planar Magnetic Over-the-Ear-Headphones, Open Back

Driver Size:

80 mm Diameter

Manufacturer Freq. Response:

20Hz – 35kHz (Driver freq. response in free-field)


98 dB

Nominal Impedance:

22 Ohms


12 Ounces (350 Grams)

Available Colors:

Silver with Black Trim


¼” (6.35 mm) Headphone Adapter, Headphone Cable (1.5 Meter or 4.9 Feet; 3.5mm Plug)


$299 USD




Hifiman, HE400S, Planar Magnetic, Headphones, Over-the-Ear, Open Back

Where to Buy:

HiFiMAN Website

Having recently garnered much critical acclaim at the high end of the market with the release of the HE1000 headphones, HiFiMAN, no doubt, is looking to bookend that success with the release of the very affordable HE400S. At an asking price of $299.00, it stands right at the entry level gateway, where serious people start spending their money for good sounding headgear. It also neatly undercuts their closed-back planer rivals, the OPPO PM-3 by 100 bucks. Let’s have a closer look at them.


HiFiMAN HE400S Planar Magnetic Headphone

HiFiMAN HE400S Planar Magnetic Headphone

The HiFiMAN HE400S headphones arrive in a nice, sturdy board box with clean, modern graphics on the outside and prodigious foam padding on the inside to help ensure safe delivery. The headphones themselves share a similar design DNA that runs through most of the HiFiMAN brand. That being the large round ear cups that are hung on horseshoe shaped brackets, attached to the ubiquitous HiFiMAN headband. Pretty much all of their headphones, save for the HE-6, share similarly designed support componentry with the major model differences being in the choice of component materials and drivers.

HiFiMAN HE400S Planar Magnetic Headphone

HiFiMAN HE400S Planar Magnetic Headphone

The HE400S have silver colored plastic ear cups and brackets with black perforated grills covering the driver backs. The ear pads themselves are covered in a very comfortable black velour with the head band being made of a soft perforated vinyl material. All this is attached to the black metal support frame. The build materials were no doubt chosen to keep the overall weight down to a comparably comfortable 350 grams, but the build quality remains admirably solid with no loose fittings or noticeable manufacturing errors. The headband and frame seem to offer a good range of movement to accommodate a variety of head sizes. The press release describes the drive units as:

HiFiMAN HE400S Planar Magnetic Headphone

HiFiMAN HE400S Planar Magnetic Headphone

“newly-designed single-ended planar magnetic drivers in open-back design that deliver the clarity, lifelike soundstage and spatial imaging that HiFiMAN is known for. Sensitivity is increased to 98dB, which allows the efficient HiFiMAN headphone to be driven easily with a portable audio device such as an iPod or smartphone though ultimate performance would only be achieved if paired with a quality amplifier. Impedance of the HE400S is 22 Ohms.”

HiFiMAN HE400S Planar Magnetic Headphone

One other design change of note is the use of new 2.5 millimeter plug-in connectors (like those on the HE1000s) to attach the headphone cable to the ear cups instead of the screw-on type connectors that HiFiMAN has used in the past. Personally, I’ve found those screw-on connectors a little bothersome in use so this is a welcome change and will no doubt spark some additional aftermarket cable options to more easily develop. Besides the detachable cable the only other accessory is a ¼ inch headphone adapter plug.


For the majority of my testing, I used the HE400S along with my iPhone 5S when on the go. At home it was connected through either an Audio GD-Compass 2 headphone amp/DAC or a Burson Conductor Virtuoso headphone amp/DAC using the supplied cables and adapter in all cases.

In Use

HiFiMAN HE400S Planar Magnetic Headphone

Having just recently reviewed, and frankly been spoiled, by the HE1000s, I was a little apprehensive about listening to the HE400S so soon afterwards. I was worried it was going to be too much of a letdown. Well, while there was naturally a fair sonic difference between the two, it was easy to hear that a good deal of what was developed to make the HE1000s sound so good must have trickled down a little to the HE400S.

A couple of years ago I had listened to a pair of the original HiFiMAN HE400 on a few occasions. It was my first experience listening to planar headphones and despite all the favorable reviews at the time, their sound just wasn’t for me. I remember finding vocals to be too recessed for my liking and the sound staging, as best as I can describe it, was over exaggerated and wonky-sounding.

Add to that, I found the overall weight and clamping force to be a little excessive for comfort. It actually soured me on the idea of ever owning planar cans for a while. Two years later, to the here and now, and these new entry level headphones sound and feel so much different and so much better to my ears.

Beginning with the tactile side of things, for being visually large headphones, the HE400S are commendably light in hand making them stress free to wear for extended listening sessions. The clamping is also light and comfortable yet sufficient to complete a good seal around the ears. I wore the HE400S for multi-hour stretches during the workday and felt completely comfortable, feeling no ill effects in my neck or on my temples.

As I mentioned in the Design section, Although the materials used in the construction of the HE400S are light in weight, they all seem of good quality and the construction is solid. After over a month of continued use, the headphones don’t show any noticeable signs of wear and nothing has come loose or feels on the verge of it. They even survived a couple of gaming sessions with my two boys, so chalk up some durability points there!

HiFiMAN HE400S Planar Magnetic Headphone

Moving on to their sonic characteristics, I would sum up the overall sound as being smooth and liquid. They are warm and engaging to listen to for long stretches and I don’t recall being fatigued by them even once. Being open back cans, the sound stage was predictably wide and appealing without becoming over exaggerated. Also, as open backs do, they will leak sound to the surrounding area. Not as much as some others do, but enough that other people around you will also be sampling your playlist as well.

So while these are meant to be driven off a portable device they may not be the best choice if you spend a lot of time on a bus or subway during your daily commute. That, however, didn’t stop me from going out for walks in my neighborhood with these cans and my iPhone and the two made for a good combination.

The HE400S were easily driven by my phone to as loud as I could want and the headphones didn’t let too much of the ambient noise intrude on my music. Driving them off either the Burson or Audio GD DAC/Amps gave me expectedly better musical detail and resolution than what my phone could muster and mainly helped the bass hit a little harder when any low notes came into play.

If I were to nitpick, the treble reproduction of the HE400S, while good, is perhaps not as crisp as it could be but to many people who are sensitive in that audio band, that can be a plus. Vocals were well reproduced sounding pretty natural for the most part. I felt as if I noticed a certain thickness to the sound in the lower-mid to upper bass region. This gave them a slightly dark quality when listening to certain types of music, jazz and blues in particular.

While this characteristic may not be immediately noticeable when you listen to the HE400S in isolation, I had a pair of HiFiMANs HE560 cans floating around here at the same time and, when comparing them back to back, the difference in transparency becomes clear. Keep in mind though, that is roughly a $600.00 difference in product and I know some people who claim to find the HE560 thin-sounding for their tastes, so take this observation for what it’s worth.

The bass quality on the HE400S is quite good as well. Kick drums and stand-up bass all sounded natural and impactful but if hip hop and techno music is more your thing these cans may not completely do the trick for you. Listening to solo piano was particularly rewarding through the HE400S, imbuing a lovely body and spaciousness to the notes. Brass and big band music also did really well with these headphones, not exhibiting any of the harshness that can sometimes come across in reproducing loud horns. And if you like to listen to live music recordings, the HE400S will also treat you right in that they do a great job in recreating a live space and the resulting sense of presence.

Just for fun, I did a quick comparison between the HE400S and the OPPO PM-3 headphones that I also happened to have around since they are close competitors in this market segment. The OPPOs differ by being closed backed in design and about 100 bucks more expensive than the HiFiMANs but, until the HE400S came along, the PM-3s were the least expensive planar magnetic headphones out there that were made to run off a portable.

The first noticeable difference when comparing the two is the visual size. While the HiFiMANs look positively massive by comparison, both headphone weigh close to the same amount as to both be equally comfortable when worn for long periods. The OPPOs are about 4dB more sensitive so they sound a touch louder than the HifiMANs at a given volume.

Sound-wise they share the similarity of having that slightly dark sound with a little extra going on in the upper bass lower-mid region. Beyond that, the soundstage is the big differentiator between the two. The OPPOs, being closed-back, have a narrow more focused image that lends itself well to well recorded studio material but can flatten out the atmosphere of some live recordings.

The HiFiMANs project that bigger image that open-backs are known for but still keep it together without getting too diffuse. That’s not saying that the HE400S lack for detail, they convey plenty of it as well, it’s just that their overall presentation is more relaxed and laid back. The OPPOs, conversely, have slightly more crisp treble and the low bass notes hit harder than on the HE400S. The OPPO also offers the added convenience of a dedicated smartphone cable with integrated volume control and mic where the HiFiMAN does not.

Ultimately I think both headphones look to be excellent value for the money and a choice will come down heavily to personal musical preference, but it’s hard to ignore the $100 price difference in favor of the HiFiMAN. Just a couple of years ago, you’d been hard pressed to find this level of sound quality anywhere near this price point let alone a headphone that wasn’t using standard dynamic drivers. I, and probably a lot of other people, could easily use the HE400S as our “daily driver” headphone and not feel a pressing need to upgrade for a good long time. Well done HiFiMAN!


HiFiMAN HE400S Planar Magnetic Headphone

THE HIFIMAN HE400S provides great sound quality at an unbeatable price point.

  • Big, wide sound stage.
  • Warm, appealing sound.
  • Light and very comfortable.
  • I can afford them!
Would Like To See
  • Include a cable with integrated volume control and mic for using headphones with a smartphone.
  • At least one other color choice, like black or dark grey.

The HiFiMAN HE400S is a superb entry level drug in the overall addiction of “audiophile” headphones. It has a lush, big soundstage and resolves plenty of detail while being comfortable to wear for extended periods. It also has the bonus of being efficient enough to be driven by a phone or mobile device so it doesn’t need to just stay in your home exclusively reserved for “serious” listening.

While it may lack the odd convenience feature associated with a road warrior’s head gear, the $299.00 price tag make these cans a veritable bargain for a pair of full size planar magnetic headphones. If about 300 bucks is your budget, you really owe it to yourself to give the HE400S an audition. It seems that HiFiMAN may introduce a whole new market of listeners to the joys of open-back planar magnetic headphone sound, which they’ve had a hand in developing and nurturing over the past few years. It’s a very good time to be an audiophile on-the-go!