“Let our rigorous testing and reviews be your guidelines to A/V equipment – not marketing slogans”
Facebook Youtube Twitter instagram pinterest

HiFiMAN HE-400S Headphones Review

By Smit Patel


  • Product Name: HE-400S
  • Manufacturer: HiFiMAN
  • Review Date: September 25, 2015 08:00
  • MSRP: $300
  • First Impression: Pretty Cool

  • Frequency response: 20Hz – 35KHz
  • Sensitivity: 98dB
  • Impedance: 22 Ohms
  • Weight: 350g
  • Cable Length: 1.5 m
  • Plug: 3.5mm/6.35mm

HE400s in case.jpgHeadphone-veteran HiFiMAN has recently launched the HE-400S, a new headphone featuring an open-back design and planar-magnetic technology. The brand has always been the inspiration behind many newcomer headphone companies and with Dr. Fang Bian behind the helm, innovative deployments are certainly never far around the corner. It is no surprise then that this, coupled with the success of the previously well-received HE-400 model has allowed the HE-400S to become a heavily anticipated release.

At a very modest price of $299, which is unheard of for an ortho-dynamic headset, the HE-400S represents an affordable investment as well as an entry path to HiFiMAN’s more expensive headphone collection. Its closest rival comes in the form of the planar-magnetic Oppo-3 headphone, which even though costs $100 more than the HE-400S, does not include an open-back design.

At 12 Oz (350 grams) the HE-400S is relatively light compared to other planar offerings.  The new ergonomic headband which HiFiMAN’s HE-1000 flagship also boasts (in metal), is designed to aid in comfort. With that said, the promising features and the low price tag look appealing to any newcomer hoping to make a break in to this seemingly endless hobby.

The Packaging

The box the HE-400S comes in is very professional and premium looking; it is clear that HiFiMAN wanted to make a statement with this new model and they have definitely succeeded in doing so. The top flap of the slide-out box opens to reveal padded foam which houses the headphones. Also included is the cable with 2.5mm jacks for the left and right connections to the housings of the headphones, a 6.5mm adapter and an instruction manual.

From first glance, I am very impressed at the packaging design that HiFiMAN have opted for; it certainly beats the rather uninspiring box that similarly-priced Philips Fidelio X2 come in.

The Design & Build

The design of the HE-400S is very much reminiscent of its flagship brother, the HE-1000 with the latter obviously sporting more a premium selection of materials. Nevertheless, both have the same type of headband mechanism which I have found to be quite excellent and innovative for adjusting the headphones to fit your head. Where the slider attaches to the metal headband, for example, I have found there to be no question of durability as the mechanism looks very robust. I also prefer this type of mechanism to the Sennheiser’s HDXXX series of headphones which have had various complaints about cracks and other issues related to build.

HE400s side2.jpg

The outer housings of the HE-400S have a silver coating which in my opinion looks great on websites and the general net but does not really look premium in person. I would much rather preferred a matt black or even a piano gloss black finish to really make these headphones stand out. For what it is worth though, the silver coating does not look to be tacky but does not really do any favors for the headphone.

The large honeycomb mesh is layered on top of the planar dynamic drivers which can be seen in direct light. This whole portion of the headphones are rotatable in both the horizontal and vertical planes giving the listener a huge amount of variations to get the perfect fit.


On the subject of fit, I have found that this headphone is exceptionally comfortable owing to the padded headband and the soft velour ear pads. The clamping force is tight at the start but does subside with a greater time of listening. I would not say that these headphones disappear after a while though, as 350 grams is still relatively heavy in the non-planar world and you can feel this weight after long-listening sessions.

HE400s side.jpg

In the hot summer seasons, certain ear pads can feel stuffy and rather claustrophobic on your ears if not done right. The HE-400S, however, features a very spacious and open set of ear pads which does not cause any of these issues and is one of the headphone’s assets with regards to comfort.

Sound impressions

The Bass

The HE-400S has all the good low-frequency traits of a planar magnetic headphone; tight, refined and responsive. The frequency response can best be characterized as neutral with good extension in the sub and mid-bass department. With that said however, there is not really an impactful bass slam nor does the 400S bass sound signature appeal to those craving for a powerful bottom-end. Instead, bass is well-placed and able to deal with a wide range of genres with its fast and accurate sound. Next to the Fostex TH500RP, the bass on the TH500RP is more visceral with a thicker tonality than the tighter and leaner, albeit weighty, HE-400S’s low-end spectrum. In comparison to previously similarly-priced Sennheiser HD598, the HE-400s wins out on sub-bass extension although there is still a discernible roll-off where the very low frequencies are concerned. It should be said then, that while the HE-400S is by no means lacking in bass, it is rather neutral and should be avoided where preferences are strongly inclined towards a thunderously impactful bass response.

The Mids

The midrange is exquisite and certainly an asset to these great pair of headphones; it is smooth, detailed and enveloping. I am impressed at how the mids sound neither too forward nor too laid back but lie in the perfect distance compared to the rest of the frequency spectrum. In Avicii’s “Hope There Is Someone”, the vocals are a pure delight retaining a sense of airiness yet still rendering an entrancing sound which combines sweet with detail. This is what this midrange is all about; a certain musicality infused with detailed dynamics which make these very engaging. Throw in the smooth non-fatiguing overtones and this is a combination which can be listened to for hours and hours. Comparing this to another planar dynamic, the Fostex TH500RP, the HiFiMAN HE-400S sounds noticeably more airy and open at the expense of the TH500RP’s fuller and richer vocal presence. Both these headphones have great midranges in their own right though, with my personal preference leaning towards the HE-400S for its ability to convey a more open and encompassing sound.

The Treble

Treble presents with good extension and is tonally smooth preventing the HE-400S from ever sounding dark. There is certainly a nice air and sparkle to tracks when looking at the treble alone however this headphone does not reach the very high frequency notes. Thus, it does lose out on detail at the extreme ends of the frequency spectrum but still has a decent enough amount of extension that nothing feels overly subdued. Both the modded Sennheiser HD558 and the HD598 eclipse the treble extension of the HE-400S resulting in a brighter sound compared to the smooth sailing HE-400S. The Sennheiser HD600, however, presents the right balance of extension and tonality that makes high frequencies on it sound much more natural compared to both its predecessors and the HE-400S.

The Matching

The HE-400S has an impedance of 22 Ohms and a sensitivity of 98db. Though a standard smartphone is capable of driving these – I have found to get the most of these, a more adept DAC/Amp is highly recommended.

The iBasso DX90

Paired to the great value iBasso DX90, the HE-400S picks up on spades of detail and headroom that was otherwise lacking when run straight out of an Asus laptop. On the 2.2.0 firmware, mids are very smooth and the soundstage is excellent. I have found that the mid-gain setting to work best for a headphone of this nature; there is very little, if any, noise floor and the synergy between these two products is great.

The Fiio X5 Second generation

Compared to the DX90, the X5ii is more musical, delivering a warmer sound with more weight behind the bass. However it does so at the expense of detail and soundstage which the DX90 particularly excels at.

Topping NX1 Amp

Driving the HE-400S out of an Asus laptop and the budget-level Topping NX1 Amp, the sound is leaner and clearer with no traces of coloration. The NX1 Amp does require to be set on high-gain to get the best out of the 400S. Minimal noise floor is to be experienced however it does not really detract from the user experience. At higher volume levels, the Topping NX1 remains clean and there is no distortion in any part of the frequency ranges; all in all, a good value for money amp.

iFi Micro iDSD

Pairing this with the HE-400S, there is immediately an excellent synergy on both the eco and normal modes. The headphone is now allowed to breathe more with a greater soundstage, energy and natural sound. This and the iBasso DX90 are my preferred choices for driving the HE-400S for their wonderfully open and addictive sound qualities they impose on the affordable HE-400S.

The Soundstage & Imaging

The soundstage of the HE-400S is above average with good projection of sound in the three dimensional planes. There is more height and width compared to depth but there is a definite out of head sound which you do not seem to get with closed back headphones.

Imaging is also above average but does succumb to headphones such as the Sennheiser HD600 and AKG Q701 in terms of instrument separation. However, the HE-400S has an excellent center-stage imaging which makes music sound very evenly balanced.

Music Listening Tests

Cry – Michael Jackson

Michael’s soulful voice is smooth and is accompanied by backing vocals which highlight the capabilities of this headphone’s soundstage. The instrumentals are harmonic and detailed with moderately speedy decays. I do feel that certain micro-nuances are ironed out when compared to reference headsets and even reference IEMs. Though this is to be expected as the HE-400S is not an analytical headphone nor is it ultra-resolving.

Dear Boy – Avicii

Vocals in this are lush, full-bodied and when accompanied by the dynamic mastering really demonstrate the musicality of the HE-400S. Though as mentioned, sub-bass really does not extend at the depth I would like it as there is a certain roll-off beyond very low frequencies. Midrange however is stellar and vocals really shine through in this very busy track.

Cello Song – The Piano Guys

Cello notes are reverberant with weight behind them, however the smooth tonality of the HE-400S does seem to take away a bit of realism from this track. Soundstage is beyond average however depth projection lags behind the height and width.

Thunderstruck – ACDC

Guitar riffs in this lack bite and aggressiveness though it can be solved with a bit of equalising. From stock however, the smooth tonality, makes electric guitars seem unnaturally tame. Some may like this but those who don’t, will certainly prefer a brighter headphone to really bring out detail from guitars and rock-led vocals.


Overall the HiFiMAN $299 offering is an entry-level model that sure does get a lot right. It is amazing how HiFiMAN were able to get the price as low as they have because this is really a great sounding set. What impressed me the most was the tonality of the midrange which is smooth, intelligible and rivals that of many other expensive headphones. Sub-bass however does leave some to be desired as there are many rivals which boast better extension and power in this department. Nevertheless, the build and sound are enough to please any budding audiophile hoping to get into the audio scene or really for anyone looking for an affordable planar model. Taking design cues from its flagship brother, the HE-400S is supremely comfortable and offers a very solid sonic experience. I very much look forward to what HiFiMAN has next in store. Stay tuned…

Unless otherwise indicated, this is a preview article for the featured product. A formal review may or may not follow in the future.