The HiFiMan HE-400i are great critical listening headphones that are not really suitable for any other use case. They're comfortable and deliver an excellent sounding audio reproduction. However, they can sound a bit sharp on already bright tracks, and they do not have as much bass as the Edition X. They also have fairly weak hinges that are not very durable, unlike the HiFiMan Sundara, and may be a deal breaker for most critical listeners.
Mediocre for mixed usage. The HiFiMan HE-400i are critical listening headphones, not intended for other use cases except maybe home theater. They deliver an great sound quality and comfortable design but have poor isolation and a bulky, cumbersome build. They are best used at home and in isolation and will not be suitable for commuting or sports.
The HE-400i are good reference headphones that shine in the sound department. They're comfortable for long listening sessions and deliver an excellent representation of instruments and vocals. They sound a little sharp and bass is a bit lacking compared to the Edition X, but their sound is sufficiently balanced and open to please most neutral listeners.
Not designed for commuting. The open ear cups do not block any noise, which is not ideal for loud environments.
Not meant for sports. They're big, bulky and slightly unstable. Even if they can be powered by a mobile device these headphones perform poorly outdoors and will fall if used during physical activity.
Sub-par for office use. They will not block the office chatter and also leak a lot. Unless you work in an isolated environment, anyone will be able to hear your audio.
Mediocre for gaming. The HiFiMan HE-400i are comfortable, they sound great and have a low latency wired design. However, they do not have a microphone for voice chat when gaming, and no customization options which are typical for most gaming headsets. Also, they do not have the convenience of wireless design or multiple connection options for an optimized experience on Xbox one or PS4.
The large and open ear cups of have a metallic finish and a slight blue tint that's eye-catching. That coupled with the soft suede padding and the old school leather headband give them a retro, yet premium appeal that will work for some. They do not look as premium as the Sundara and they're a bit too bulky to wear out in public, but they're not designed for outdoors so it shouldn't be too much of an issue.
The HiFiMan HE-400i are comfortable, well-padded headphones. They're a bit tight on the head, but the suede-like material used for the padding is soft and pleasant on the skin. The ear cups are not as large as the Edition X, and the padding touches the tips of some listeners'ears. However, this smaller format might be more comfortable for some than the oversized ear cups of the more premium model.
These headphones do not have any controls.
The HiFiMan HE-400i, like the rest of the planar magnetic HifiMan headphones, are not very breathable. They have an open back design which usually does not get as hot as closed back over-ears. Unfortunately, since they are planar magnetic headphones, the larger drivers obstruct a good amount of airflow, so they will make your ears fairly warm after a couple of hours of continuous listening. You will have to take breaks if you have long continuous listening sessions when compared to some other over-ears like the Sennheiser HD 700.
The HiFiMan HE-400i are big and not portable. They're a bit too cumbersome to comfortably carry on your person and do not fold into a more compact format. The ear cups lay flat but are bigger than average over-ear models, which doesn't save much space. On the upside, they are a little smaller than the Edition X, but you will still need a backpack or a large bag to transport these headphones. Also, they don't come with a protective case or pouch.
The HiFiMan HE-400i have a good build quality. They make use of premium materials, which results in a sturdy design that can handle a fair amount of physical stress. The ear cups are not as well-built as the Edition X's ear cups. However, the plastic joints connecting the frame to the ear cups is thicker and sturdier, which makes these headphones slightly more durable.
Update 12/04/2018: Multiple users have experienced a build quality defect, resulting in broken hinges/yokes under mild stress. We have therefore adjusted our build quality score to reflect this manufacturing issue.
These are not sports headphones. The large over-ear cups will sway and quickly slip off your ears if used during exercise or while running. They're a bit more stable than the Edition X and will maintain their position during casual or critical listening sessions.
The HiFiMan HE-400i have a great frequency response consistency. The maximum amount of deviation across our five human subjects is less than 3dB at 20Hz, but the deviation happens across a very narrow range and the rest of the bass region is exceptionally consistent. The treble delivery is also very consistent across multiple re-seat, with the maximum deviation below 10KHz being less than 2dB.
The bass of the HE-400i is very good. The LFE (low-frequency extension) of 54Hz is decent, but not great. Also, low-bass which is responsible for the thump and rumble common to bass-heavy music is lacking by more than 5dB. So their sub-bass may not be heavy enough for the fans of heavy bass. Mid-bass, responsible for the body of bass guitars and the punch of kick drums, is also lacking by about 1dB, but this effect will be very subtle. High-bass, responsible for warmth is quite flat and over our neutral target by just 1dB.
The mid-range is great. The response is flat throughout the range, which indicates a well-balanced reproduction of vocals and lead instruments. But low-mid and mid-mid are above our target by about 2dB. This thickens the body of vocals and lead instruments a bit, however, it won't be noticeable to most people. High-bass is within 0.6dB of our neutral target, which is great.
The treble performance is very good. Low-treble is relatively even and flat. It is overemphasized by just 1.2dB, which won't be very noticeable. However, the +5dB bump in the sibilance range (6KHz-10KHz) makes the S and T sounds, mostly heard on vocals and cymbals, a bit bright and piercing, especially on overly bright tracks. The newer HiFiMan Sundara have a slightly better balanced sibilance range.
The imaging performance is great. Weighted group delay is at 0.15, which is very good. The GD graph also shows that the entire group delay response is below the audibility threshold. This ensures a tight bass and a transparent treble reproduction. Additionally, the L/R drivers of our test unit were very well-matched in frequency, amplitude, and phase response, ensuring accurate placement and localization of objects (voices, instruments, and video game effects) in the stereo image.
The soundstage performance of the HE-400i is good. The PRTF graph shows a good amount of accuracy, and a decent amount of pinna interaction/activation. However, the notch around the 10KHz region is not very accurate or deep, which suggests a soundstage that is relatively natural and large but located inside the listener's head. Also, because of their very open enclosure, their soundstage will be perceived to be more open than that of closed-back headphones.
The HiFiMan HE-400i have a poor isolation. The architecture of these headphones is completely open, and therefore block very little noise. In the bass range, where the rumble of airplane and bus engines sits, they don't achieve any isolation. In the mid-range, which is important for blocking out speech, they don't isolate at all either. In the treble range, occupied by sharp sounds like S and Ts, they achieve about 5dB of isolation, which is barely noticeable.
The HiFiMan HE-400i have a poor leakage performance. These are the one of the loudest and leakiest headphones we have measured so far. Not only the level of the leakage is extremely high, the profile is extremely broad too. Most headphones either level off at higher frequencies, or roll-off, but similar to the Edition X and Sundara, the HE-400i keeps getting louder as the frequency rises. The significant portion of their leakage is between 300Hz and 20KHz. In terms of loudness, with the music at 100dB SPL, the leakage at 1 foot away averages at 67dB SPL and peaks at 86dB SPL, which is a lot louder than the noise floor of an average office.
These headphones do not have a microphone so the recording quality has not been tested.
The HE400i do not have a microphone so the noise handling has not been tested.
These headphones do not have any active components and do not require a battery.
These headphones do not come with an app or software for added customization options.
These headphones are wired and do not have a Bluetooth connection. If you want a good-sounding wireless headset, then consider the Bose QuietComfort 35 II.
The wired connection of these headphones has negligible latency which is suitable for gaming and home-theater use. Unfortunately, they will not have the range and convenience of wireless headsets
The HiFiMan HE-400i, like the Sundara, have a simple 1/8TRS audio cable with no in-line remote/microphone. They will only provide audio when connected to your PS4, Xbox One or PC.
The HiFiMan HE 400i do not have a dock. If you need a headset with a dock that also has a wired connection for gaming or watching movies, then consider the SteelSeries Arctis 7.
The Hifiman HE-400i are great-sounding headphones with a comfortable fit and a balanced audio reproduction. They're a good choice for critical listening but will not be as good for other use cases. Unfortunately, their build quality, though premium looking is a bit fragile and weak at the hinges. This may be a deal breaker for some, especially since similarly designed models, like the ones compared below, have an equally as good sound but a better build quality. See our recommendations for the best studio headphones, the best DJ headphones, and the best over-ear headphones.
The HiFiMan HE-400i and the HiFiMan Sundara are fairly similar models, but the Sundara are better headphones. They are better-built than the HE-400i and they don’t sound as sharp in the treble range. However, these differences are fairly minor, and the HE-400i might offer better value for some since they are cheaper.
The Beyerdynamic DT 990 PRO and the HiFiMan HE-400i are both good headphones if you like a neutral sound. The HiFiMan have less bass, but they also sound less piercing. They have a much more immersive soundstage as well. However, they feel a lot less durable, and there have been many reports of issues with their build quality. The Beyerdynamic feel much better-built, although their tight fit is less comfortable.