HIFIMAN HE 400i Review – Planar Magnetic Open Headphones

HIFIMAN HE 400i Review – Planar Magnetic Open Headphones

HIFIMAN HE 400i Planar Magnetic Headphones


Build Quality & Durability


Comfort & Ventilation


Planar Magnetic Driver Performance


Accurate Imaging


Easy To Drive



  • Extremely Crisp & Detailed Highs
  • Wide & Accurate Bass Response
  • Can Be Used With/Without A DAC/Amp
  • No Burn-In Time Required
  • FocusPads Provide Above-Average Cushion


  • Uses F-connector Headphone Cable
  • Suspended Headband Doesn't Provide The Best Weight Distribution

Are you looking for a great entry-level pair of open planar magnetic headphones? Did someone recommend you try a pair of HIFIMAN? Planar magnetic headphones are well-known for producing extremely authentic and well-balanced playback. Although that much is true – not all headphones were created equally – which is why we think you’ll enjoy our detailed analysis. 

We’ll cover each of the most important performance aspects to consider before making your decision. By the end of our review, you’ll have a pretty good idea about whether or not they’re the right choice for you! Read through our HIFIMAN HE 400i Review to see if they can compete with some of the other most popular open cans!

Our HIFIMAN HE 400i Review

HIFIMAN HE 400i Review - Planar Magnetic Open Headphones

Features & Technical Specs:

Circumaural (over-ear) headphone design

  • Open-back ear cups (for added ventilation & wider soundstage)
  • Includes 3.5 mm headphone cable and 1/4″ adapter 
  • Features a lighter build than other similar cans
  • Headphone Cable: f-connector to 3.5 mm 
  • Driver Type: Planar Magnetic
  • Frequency Response: 20 Hz – 35 kHz
  • Impedance: 35 Ohms
  • Weight: 13.05 ounces
  • Dimensions:
     8 x 7 x 4.5 inches

Before you move on, take a quick look at the links below that you can use to navigate our review. Each section will provide an in-depth analysis of each individual performance aspect.

Here are the 5 most important performance features you’ll want to consider before making your decision:

  1. Build Quality & Durability
  2. Comfort & Ventilation
  3. Planar Magnetic Drivers
  4. Sonic Performance – A Detailed Breakdown
  5. Who Are The HE 400i Ideal For?

Now that you’ve taken a quick look at the technical specs, let’s start by examining two of the most important features – build quality and design.

Build Quality & Durability

While you were skimming the technical specs above, you may have noticed how much these cans weigh. At only 13.05 ounces, these are one of the most lightweight planar magnetic cans out there. Does less weight mean lower quality build materials? Not necessarily, but let’s take a closer look. 

As you’re holding these cans, you’ll notice that the adjustable headband has an extremely satisfying click as you make each adjustment. (That’s always a good sign.) You’ll also notice the suspended strap just under the headband, which we’ll cover in more detail below

They also have 180° rotating circumaural (over-ear) ear cups that allow you to place your ‘phones face down on a table or desk. Both ear cups have circular FocusPads providing the cushion for staying comfy during longer listening sessions. The black screen covering the outside of each ear cup is well constructed and has the evenly-spaced ventilation you’d expect to see.

Also included is a 5-foot f-connector to right angle 3.5 mm headphone cable. The cable itself is covered with high-quality fabric. There is also plenty of room in between each respective connector, which allows for more freedom of movement while you’re listening. 

F-Connector - HIFIMAN HE 400i Review

In the picture above, you can see the f-connector inputs on the outer edge of the ear cup. Connecting the cable to the headphones can be somewhat tedious at first if you’re used to using the more standard 3.5 mm connector. 

The f-connector to right angle 3.5 mm cable was most likely designed for better portable use, but since the open cups will allow sound to leak out around you – outdoor/public use isn’t ideal. 

One benefit of separate inputs for each ear cup is that it allows for an even electrical signal sent to be sent directly to each ear. In terms of audio, this helps create the well-balanced, even soundscape that you’re probably looking for. 

The f-connector to right angle 3.5 mm cable was most likely designed to improve portable use, but since the open cups will leak sound – they’re not exactly ideal for outdoor or public usage. 

Lightweight or Flimsy?

Now that we’ve covered the basic construction, let’s examine how well they hold up after hours and hours of use. Although pretty few and far between, there have been some issues with the inner ear cup components coming apart after fairly heavy usage. For example, the wool inside each driver flopping around while music is playing, or in some cases, the ear cups starting to fall off.

Taking care of them and storing them using a headphone stand will dramatically extend their lifespan. Examples (like the 2 listed above) are usually caused by either a lack of proper storage – or an accidental drop.

For the most part, these cans are built with lightweight materials of above-average quality. Although the build quality isn’t quite as solid and sturdy as other competing models – HIFIMAN made sure to include at least base-level durability for open cans in this price range. 

Comfort & Ventilation

Headphones with a lightweight build design usually cause less stress on the top of your head and lower pressure around your ears. The circular FocusPads briefly mentioned above, are made of a hybrid combination of velour and pleather. 

The hybrid combination offers slightly more ventilation than all-velour ear pads. The FocusPads provide so much cushion that you can easily wear these cans with a pair of glasses. They also have a very light clamp that makes them ideal for at-home listening or studio use. A lighter clamp means there will be less pressure around your ears, which is why these aren’t ideal for active use.

They’re far better-suited for kicking back and enjoying their sonic performance – (not for taking with you on a jog). They perform very well in the mixing/studio environment aside from recording since their open design will allow ambient noise to leak inwards.

Suspended Headband - HIFIMAN HE 400i Review

As you can see in the picture above, the thick suspended strap just under the headband was designed to provide even weight distribution. While it does provide above-average even weight distribution, the design isn’t perfect. Due to the actual shape of the suspended strap, it just barely misses the mark.

The headband shape (thicker in the middle than the edges) doesn’t do the best job at automatically adjusting to the shape of your head. Nonetheless, the suspended strap does take care of most of the wearing weight pulling down on the top of your head. 

One more important factor to keep in mind is that if you have a bigger head, the headband adjustment slider might not extend quite far enough for the most comfortable fit. Also, regardless of your head size/shape, you will probably have to physically take them off your head to find the right adjustment.

Overall, the improvements on comfort (especially compared to earlier HIFIMAN models) dramatically add to the long-lasting wearing comfort. Which brings us to the planar magnetic drivers bringing your music to life. 

Planar Magnetic Drivers

Understanding the difference between planar magnetic and dynamic drivers is important for knowing why planar magnetic has a distinctly different sound than other ‘phones. It’s also good to know what type of audio playback you can expect before you go out and buy a new pair without a second thought. 

Why are planar magnetic headphones so popular in the audiophile community? The way these drivers are constructed enables for the most well-balanced, natural headphone performance possible. Here’s a brief explanation of how they work. 

2 Magnets + A Diaphragm = Accurate & Well Balanced Playback

To help visualize what a planar magnetic driver looks like, picture an ice cream sandwich. Planar magnetic drivers have a similar structure (except there aren’t any cookies or ice cream).

Each driver has a magnet where the cookies would be. In between the magnets, is a very fragile and thin, flexible diaphragm (where the ice cream goes). 

The magnets on both sides of the diaphragm evenly line up with the diaphragm (that’s about 1/10 the width of a human hair). As the electrical current travels from your music player to each driver – the diaphragm is pushed and pulled back and forth. This movement (activated by the current) creates the audio signal that you hear when you listen to music. 

Why is this important? Since the diaphragm evenly lines up with both magnets on either side – the pushing and pulling produce some of the most well-balanced and accurate audio you’ll ever hear. It also creates a much more spacious and open soundscape that open back cans with dynamic drivers simply can’t pull off. 

Sensitive Sound Profile

The HE 400i specifically, have a sensitive sound profile that’s able to reproduce the smallest electrical inputs. This makes them fairly easy to drive by simply plugging them directly into your laptop or portable DAP. 

This also means that you won’t necessarily need a headphone amp in order to have an enjoyable listening experience. The main possible drawback being if you decide to use them without an amp, you might find that you want slightly more volume. 

It’s pretty difficult to find other planar magnetic cans (especially in this price range) that don’t have to be paired with a powerful DAC/amp like the Audioquest Dragonfly Red. (Which is also why these cans are a great entry-level open headphone.) Do they require any burn-in time?

Required Burn-In Time

Many planar magnetic headphones require a certain amount of ‘burn-in’ time. On average, after you’ve played around 50+ hours of audio through your cans – the sound of the playback starts to change. 

After the initial burn-in period (that varies by model), the headphones start performing as they were intended to. The HE 400i does not require very much burn-in time (if any at all). 

If this will be your first experience with planar magnetic cans, allowing your ears to adjust to the neutral response is the main adjustment that will take place. Even after around 250 hours of use, the neutral response remains almost identical to the way they sounded right out of the box. Now let’s take a detailed look at their sonic performance. 

Sonic Performance – A Detailed Breakdown

These cans are often compared to the Sennheiser HD 600 since they both produce fairly similar playback. That being said, there are a few pretty major differences worth pointing out. If you’ve ever used the HD 600, you know that they are hands down – one of (if not the most) analytical pairs of headphones you’ll ever try.

The HE 400i on the other hand, are also extremely well-balanced but not quite as neutral. Their sound profile tends to lean towards a slightly less analytical but still very detailed soundscape. If they’re not 100% analytical, which frequencies stand out?

Sonic Performance - HIFIMAN HE 400i Review


Lows, Mids, & Highs

The low-end bass presence is far more immense and extended than the HD 600. Instead of producing a tightly contained thumping bass that becomes distorted, they are smoothly rolled off and adequately separated from the rest of the mix. Compared to the bass response of the Philips Fidelio X2/27, the 400i are significantly less-focused on showcasing the low end. 

In the mid-range the presentation is light and full but very non-aggressive. There aren’t any audible issues with excessive sibilance on vocals either. The detailed mid-range clearly makes its presence known while gently existing in the center of the soundstage

Which frequencies stand out? The highs. The highs are extremely crisp while managing to stay within reasonable limits. Their refreshing and clean presence is extended far above the capabilities of most headphones – planar magnetic or not. Their highly detailed quality sandwiching the mids between the extended bass response creates a vastly spacious soundstage.

Detail Separation & Imaging

The highly-accurate center imaging is complimented very nicely by the huge soundstage. Due to the fast planar drivers, these cans have a very transient response. They’re extremely quick to adjust to each frequency without producing overly-lingering low, mid, or high frequencies. This results in absolutely ZERO distortion of other interruption rippling through the rest of the track.  

Since there is so much clean detail separation, the extended treble can be a little bit overwhelming if you’re not used to the slightly elevated response. If this will be your first experience with open or planar magnetic headphones, you may go through a slight adjustment period

If you’re used to using headphones that neglect or under-represent the upper range, these cans will either be very refreshing or like a splash of cold water on your face. (Okay, maybe not that extreme, but it may take some getting used to.)

Overall, the sonic performance of these cans is extremely accurate and just to the left of completely neutral. Their slight tendency to reach up a lot higher than most cans, adds to the lively representation that you’d be missing out on otherwise. 

Who Are The HE 400i Ideal For?

The HE 400i would be the ideal choice for you if you enjoy a neutral sound profile that slightly favors an extended upper range. If you like listening to music that has a strong low-end presence, but also wants to be able to clearly hear the rest of the mix – we recommend giving these a try. 

In terms of build quality and comfort, they leave very little to be desired. (As long as you’re comfortable living with the possibility that you might not be 100% satisfied with the f-connector headphone cable.) Headphones are constantly evolving and these cans mark an important step along the way. 

The only reason you might want to avoid these cans is if you only crave a completely analytical and flat sound profile. While analytical headphones definitely have their place, the soundstage offered by the 400i takes a slightly different approach. We hope our HIFIMAN HE 400i Review helped you understand why these are such a great entry-level pair of open planar magnetic headphones.

For one more brief overview, take a look at the review table below. There, you can see the main pros/cons, as well as the main criteria we used to calculate our final rating (out of 10).

If you still have more questions, feel free to ask in the comment section below! What has your experience been with other HIFIMAN or open headphones? Do you prefer planar magnetic cans, or will this be your first time giving them a try? 

If you’d like to see more information or the most current pricing info, click the link below!

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Thanks for stopping by to check out our review, we look forward to hearing from you!

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