Hifiman HE400i (all revisions)

I don’t believe that that there has been a thread for the HE400i, HE4XX, HE400i 2020 etc, so I think they can all be included in this thread.

(@DarthPool, please make any title changes or movements you feel necessary)

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Here is my review of the Hifiman HE400i 2020. As usual, this is also available on my blog and on Youtube (in Spanish).

As always, let me first point out that these headphones were sent to me for review by Hifiman, for which I am very grateful. They have not requested anything in exchange, nor am I receiving anything in exchange for this review. My opinions of these headphones will be my own personal and honest opinions, however, it has not cost me anything to test these headphones.

About the HE400i 2020…

These headphones are an updated version of a model that already existed, the HE400i, which I believe are also related to the HE4XX available from Drop. I cannot comment on comparisons between this 2020 version and other versions of this model, as I have not heard them.

These headphones are available for 169$ on HIfiman’s website, which I believe makes them their cheapest option as far as over ear headphones, that sort of answers my question last week when reviewing the Deva and asking if their were any cheaper planar magnetic alternatives. Hifiiman report them to have a frequency response of 20Hz to 35kHz and a sensitivity of 93dB with an impedance of 35Ohms.

Build and comfort…

The build of the HE400i 2020 follow the latest design used by Hifiman on their headphones, at least in the lower price brackets, being very similar to that of the Deva.

The headband is nicely padded, with a faux leather covering that does feel a little rubbery, but is comfortable on the head even for longer listening sessions.

There is plenty of adjustment in the cups, with a good amount of extension and it should be able to find the correct positioning for each individual, even though comfort is obviously a very personal thing.

The pads are hybrid, with faux leather on the outside and a material which I believe is some kind of velour that touches against your face. Personally, I am not a fan of the material they have used on the inside of the pads as it seems to get warm very quickly and also causes a little irritation, but again, that is something personal and it probably worth considering that it is summer here and the temperatures hit 40ºC daily.

The openings of the pads are also a little small in my opinion, with my ears touching them, but once more that is a personal thing.

One thing that is worth noting is driver flex. When putting on or just moving the headphones on your head, it is quite easy to notice the sound of the planar magnetic drivers flexing. This is something that I had not noticed on other Hifiman models.

So, as far as overall build, I have a few personal complaints in regards to comfort, but the only one that is not something personal is the driver flex.


My first impression of the HE400i 2020 was that it is different from the Hifiman sound I have heard from them in the past. There is a bigger presence of bass and it is a lot less bright than other headphones in their lower price brackets (I haven’t had the pleasure of experiencing their higher end offerings yet).

As far as sub bass, it extends pretty low, much lower than I would have expected, producing some rumble in songs like Nara by E.S Posthumus or Bury A Friend by Billie Eilish. In the higher bass regions there is also more presence than I would have expected from a planar magnetic driver under the Hifiman brand.

However, when tracks start getting busy in the bass area, the drivers do struggle to keep up and when there are multiple instruments occupying the same frequency range, things start to get muddy.

When moving up to the lower mid frequencies, it seems that the bass bleeds over into these lower mids, creating more of the muddyness and lack of definition. When tracks are simpler in the lower regions, the mids are presented in a much better way than when they are competing against the bass.

Higher in mid range, voices are not presented badly but again seem to be lacking definition, especially when the lower regions are busy, voices becom recessed. The HE400i 2020 is missing the clarity which is usually presented by planar magnetic drivers and gives the impression of being compressed.

Up in the treble area, things are ok but are again not great. There is a touch of sibilance, nothing major in comparison to headphones from brands like Beyerdynamic, but still slightly more than I enjoy. The treble is again not quite as defined as I would expect from a planar magnetic driver and is missing a little more in the higher registries on occasions.

With regards to definition and speed, as I have said above, they are not great in this regard. As soon as tracks start becoming busy, the drivers struggle to keep up the pace and lose a lot of definition.

As far as soundstage and imaging, they are not bad in this regard. They are not the widest soundstage I have heard but are certainly not narrow and the typical test of “Letter” or “Bubble” by Yoshi Horikawa give good results as far as the placement of images.

Timbre, however, is not a strong point on the HE400i 2020 either. The excessive bass with the recess on occasions in the mids means that some instruments, specifically acoustic instruments, sound a little artificial and are not quite right.

One final thing to take into consideration is that these headphones take a fair bit of power to actually start to push them. For my normal listening levels I was between 11 and 12 o’clock on the Atom on high gain and I am not someone who listens very loud.


The Hifiman HE400i 2020 is a budget orientated headphone that I believe is aimed towards those that are staring out in the headphone world and want to try out planar-magnetic headphones without breaking the bank.

The overall build and comfort of these is more than acceptable for their price point (even though I do personally have a couple of comfort issues) and I don’t have any complaints.

Where the headphones are not for me is in both the overall sound signature and the performance in general.

The issue I have mentioned with driver flex is something that appears on many headphones, some worse than others, and once they are seated correctly on your head, it is not really an issue but is something worth noting and could be irritating for many, especially those who don’t know what driver flex is (which would apply to many of those starting out in this hobby, to whom I feel these headphones are aimed).

However, even without the issue of driver flex, the overall compressed feeling to the sound, along with the muddiness created by the lack of definition, make me move away from these headphones and feel that it is worth considering other options.

For those that are wanting to try out planar-magnetic options, Hifiman probably has the best competition to these headphones in their own house. The Deva which are only slightly more expensive or directly the Sundara for those willing to invest a little more to receive a lot more in exchange.

I have refrained from doing direct comparisons in this review against the Deva, as I wanted to judge the HE400i 2020 on its own terms but I will post a direct comparison in the very near future, helping grasp the differences between the two.

As I said at the beginning, these are $169 headphones and I feel that it shows. They have the looks, build and specs of much higher priced offerings but are not capable of delivering what the higher priced ones do.


I had the second revision of the he-400i, the ones with 2,5 mm connectors. I didn’t like the weird midrange recession that made them sound like some parts of the music was being played under water, or in a cave. I sold them after just a few weeks. I also didn’t like the lack of punch and slam, but maybe that is more related to general differences between planar and dynamic headphones.

Does the SQ of the 4xx improve on the 400i in any way?

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No idea how the latest 400i compares to the HE 4XX. I have been using a pair of HE 4XX for the past year and like them very much. I use them with an Onkyo 7030
CD player (Transport only) and a Schiit Modius DAC/ Asgard 3 Amp combo. A nice affordable system that actually sounds good.

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I have the 2020 revision and would agree with the review. If you want an idea of what a planar does this is a relatively cheap way to do it. But I wouldn’t call this a good headphone.

They get hot and I don’t find them and particularly comfortable for extended listening.

The frequency response is wonky and tembre is not natural.

If you’re just starting out, spend the extra $30 and get the 6XX.

I have no experience with the other revisions so I can’t make comparisons.


Released 6 and a half years ago; 14,283 posts about it on head-fi, and Drop lists its version as having sold 39.5k units. Not bad for a headphone that has a plasticky sound, a wonky and piercing treble, and the other problems mentioned above.

I think the 400i’s popularity stems, in part, from it being fairly easy to drive, for all the hype, and for its price, which has been $250 or less for four years or so. (It’s bonkers to think that the 400i started life at a price of $500.) How many affordable planar headphones were there in 2015-2016? HiFiman did well to clean up in this market. It stills does, apparently. How many affordable, entry-level planars are there today? The Fostex T50RP comes to mind, then the Monolith stuff.

Yes! And we can take comfort from the fact that the HD650/6XX thread on head-fi has 43,597 posts and that Drop has now sold 109.8k of the HD6XX. You could probably make a case for these two headphones being bellwethers for changes (and the expansion) of the hobby over the last 5 years. Still, it’s striking that we had no thread for the 400i on this forum until earlier today…


That does sound like a nice, enjoyable setup - I had the 400i several years ago, at that pivot point where I bought a DAC and an amp and started getting into headphones seriously. It was my gateway headphone. I didn’t mind the treble at first, and the plasticky sound wasn’t entirely unappealing: I liked how fast it was, compared with anything I’d heard before. I still have a soft spot for it. I’m glad you’re enjoying the HE 4XX.

Edit: to clarify, I’ve not heard the HE 4XX, so my impressions are only for the 400i.

Based on comments from some guys on forums here in Spain, plus what I have read elsewhere about the 400i and the 4XX, it seems that the 2020 has changed quite a lot.

It’s a shame I don’t have (and haven’t heard) the other versions as it would have been great to compare.

Thanks! The law of diminishing returns comes up quickly in this hobby, so it’s helpful
to be able to identify great value components that can keep you from
chasing the latest flavor of the month gear.

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Yes, you’re entirely right! I spent a lot of time calculating the sweet spot for investing in the hobby - getting gear that was priced right, for me, and that would last me a good, long while before I’d need to upgrade it. (My DAC and amp are the Drop counterparts to your Schiit stack, the Airist RDAC and the MCTH).

I bet your Asgard 3 pairs well with the HE 4XX - plenty of power and a nice bit of warmth to balance with the headphones. I bet you’re in one of those sweet spots, too.


I still have my HE400i but its the original SMC jack version with the back plate so it sounds quite different from any of the other revisions. I’ve heard the 2.5mm jack version and the newer 3.5mm jack version and I have to agree that they are quite different from mine but then again I paid $475 for them back in 2014 and I’ve also modded them with sorbothane in the cups and attenuation rings in the ear pads. I pretty much only use them on my Project Ember or Lyr2 out of a Bifrost Uber or Modi2uber, with the Bifrost MB they have a slightly sharp edge with some tracks that gets irritating to me at times.

Excellent review @SenyorC.

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Thank you @prfallon69, as always!

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Actually the A3 works well with every headphone I have including: HD600, HD6XX, HE 4XX, T50RP MK3 etc. It’s an excellent all-rounder for under $200. I use a LOKI Mini
to fine tune each headphone and that also works well.

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That’s a great collection! I’ve heard that the A3 is versatile, and I really ought to give the Loki a whirl. I should think you’d be covered for pretty much any genre of music with this set of headphones!

Thanks! Yes, it 's a good all around system. It may not be as good as the TOTL
systems, however, it gets close enough for me and at a small fraction of the price.

The LOKI Mini is really nice for the money. I’d recommend it to anyone in this
hobby for its flexibility. The mainstay of my system is Modius DAC feeding the
LOKI. Then I rotate sources, headphone amp’s and headphones in and out
of the system. It’s a lot of fun, especially given the endless source of music
to be found in the Internet.


I’m curious, how do you determine if you have a driver flex situation? Is it something you feel? Is it a rattling sound of some kind?

If you are sure there is a driver flex, can you repair it by taking the cups apart and tightening the driver assembly?

Also, what is a “compressed feeling to the sound” mean. Is that like a flac turning into an mp3 or something audible like that?



The way I would describe driver flex is like putting a thin sheet of plastic over the end of a pipe and then blow or suck on the other end, the noise that the plastic sheet makes when it moves in or out is like what you experience with driver flex (to be honest, it is sort of the same thing). I’m sure someone could explain it better in English than I can.

As far as the compressed sound, it is like taking the detail and squishing it together. If you are familiar with the loudness wars in recordings, this is the same sort of thing, there isn’t much dynamic range and everything sort of becomes one big sound.

I hope that helps!


Yeah, it does, thanks. Is driver flex a defect? Or is it something you kind of have to live with if you encounter it?

Personally, I would call it a design flaw but to be honest, I am no expert on the matter.

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