The Hifiman Sundara are great-sounding and comfortable critical listening headphones. They're better-built and more durable than HE-400i and deliver a sound quality that's closer to the Edition X but with slightly less bass. However, like most open-back headphones, they're not designed for other use cases but critical listening.
The HiFiMan Sundara have a better design and build quality than the HE-400i. They look somewhat similar, but they have a much more polished build quality with thinner, better-built ear cups and sturdier hinges. The new hinge/yoke design is less likely to break under physical stress, which was an issue with some of the other HiFiman models. However, it also makes the fit of the Sundaras tighter on the head, since the hinges do not swivel. Also, like most similarly designed open-back headphones, they are not meant to be used outdoors or for sports.
The Hifiman Sundara look like a better designed HE-400i. They feel a lot more premium thanks to their mostly metal design and the thinner, sleeker-looking ear cups. The headband also has a lower profile and doesn't protrude like the HE-400i or the Edition X. Also the matte finish on the all-black color scheme makes the overall style of these headphones feel very high-end. Overall these headphones are one of the better-looking open-back over-ears that we've tested and feel like a definite upgrade to the HifiMan design language.
The Hifiman Sundara are comfortable headphones, but they can be a bit tight on the head. They have large, roomy ear cups that are well padded and a rounded headband design that fits better on your head than the HE-400i. Unfortunately, the headband hinges/yokes do not swivel like on the HE-400i which makes these headphones feel a bit tighter on the head. On the upside, since they are well padded, you do not feel the pressure as much as some of the other over-ears we've tested, making them comfortable enough to wear for long listening sessions.
These headphones do not have any controls.
The Sundara are not the most breathable headphones despite being open-back. Since they are planar magnetic headphones, the larger drivers obstruct a good amount of airflow, so even with the open design they will still make your ears fairly warm after a couple of hours of continuous listening. They are not much worse than typical closed-back over-ear headphones and even have slightly better, more breathable pads than the HE-400i, but you may need to take more breaks during long listening sessions compared to other open-back headphones like the Sennheiser HD 700.
The HE-400i are big, bulky headphones, not meant for outdoor use. They're too cumbersome to comfortably carry on your person and do not fold into a more compact format. The ear cup hinges also do not swivel so they will not lay flat like the HE-400i. They are a little smaller than the Edition X and the Sennheiser HD 800 S, 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 Sundara are a great upgrade to the HE-400i in terms of build quality. They have a mostly metal design that feels durable and premium. The ear cup hinges/yokes especially have been redesigned, to better handle physical stress. They do not swivel anymore and are made from a single piece of metal that will not crack as easily as the plastic yokes on the HE-400i. The ear cups also feel better built and more high-end, since the grills on the open-back cups do not move around like on the previous model. The headband strap and the plastic pieces connecting the yokes to the headband look like the most susceptible points on these headphones, but overall they should be more durable than most of the other HiFiMan designs.
Update Unfortunately, poor quality control by HifiMan means some models have a few driver issues. We've updated the score accordingly.
The Hifiman Sundara is a very good sounding pair of open-back over-ear headphones. They have a consistent and well-balanced bass, a nearly flawless mid-range which is great for vocals, and a very good treble. They also have exceptional imaging, and a good soundstage, outperforming most of the headphones we have measured. However, their bass lacks a bit of thump and kick, and may not be deep enough for the fans of bass-heavy genres, especially since they have a noticeably bright treble. Compared to the HE-400i, the Sundara is slightly less bright sounding and produces less distortion.
The Sundara have a very good bass. The LFE (low-frequency extension) of 41Hz, is good, but not great. Accordingly, low-bass is lacking by almost 4dB, which means these headphones lack a bit of thump and rumble so their bass may not be heavy enough for the fans of bass-heavy genres like EDM, Hip-hop and Dubstep. 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.
The mid-range is great. The response is even and flat throughout the range, suggesting 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, but won't be noticeable to most.
The treble of the HiFiMan Sundara is very good. The response is relatively even and well-balanced. It is consistently over our neutral target by a couple of dB. This is mostly noticeable in the sibilance range (6KHz-10KHz) where there is as much as 5dB of overemphasis. This makes the S and T sounds, mostly heard on vocals and cymbals, a bit bright and piercing, especially on overly bright tracks.
The frequency response consistency is great. The maximum amount of deviation across our five human subjects is about 3dB at 20Hz, but the rest of the bass range is exceptionally consistent. The treble delivery is also very consistent across multiple re-seat, with the maximum deviation below 10KHz being less than 3dB.
The imaging of the Sundara is great. Weighted group delay is at 0.2 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 is good. The PRTF graph shows a good amount of accuracy, and a decent amount of pinna interaction/activation. However, there is no "10KHz notch" present. This 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 harmonic distortion performance is very good. The amount of THD throughout the range is within good limits, and doesn't change dramatically under heavier loads either. The peak in THD around 6KHz however, is rather elevated and could make the sound of that region a bit harsh and brittle. Compared to the HE-400i, the Sundara show less THD, especially in the mid-range.
The HiFiMan Sundara have a poor isolation performance which is to be expected for an open-back critical listening headphone. They're not designed to block ambient noise and therefore are not suitable to be used in loud environments or outdoors. The open ear cups help create a spacious soundstage but also let noise seep into your audio and leak a lot. This means that these headphones are best used in isolation where the leakage level will not be distracting to those around you, and you can take full advantage of the open-back design and good soundstage.
The isolation performance is poor. Due to their open-back design, they don't achieve any isolation in the bass and mid ranges, which are important for blocking out the low rumbling sounds of airplane and bus engines, as well as speech. In the treble range, occupied by sharp sounds like S and Ts, they reduce outside noise by about 5dB, which is barely noticeable.
The leakage performance is quite poor. Open-back planar magnetic headphones like the Edition X and HE-400i tend to have the loudest leakage due to the bi-directional nature of their design, and the HiFiMan Sundara is no exception. The significant portion of their leakage is between 300Hz and 20KHz which is a very broad range, resulting in a leakage that is relatively full-bodied and very bright. The overall level of the leakage is very loud too. With the music at 100dB SPL, the average leakage is about 70dB SPL, and peaking at 90dB SPL at 1 foot away.
These headphones do not have a microphone. For an open-back headphone with a microphone, check out the Sennheiser Game One.
The HiFiMan Sundara do not have a microphone, therefore, recording quality has not been tested.
The HiFiMan Sundara do not have a microphone, therefore, noise handling has not been tested.
The Sundara are passive headphones with no battery or app support.
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.
The HiFiMan Sundara have a simple 1/8"TRS audio cable with no in-line remote. They will only provide audio when connected to your console or PC and have practically no latency since they are wired. However, this also means that they will not have the range and convenience of wireless headphones.
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 Sundara have a simple 1/8TRS audio cable with no in-line remote/microphone, so they will only provide audio when connected to your PS4, Xbox One or PC.
The HiFiMan Sundara 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.
These headphones do not have a wireless range since they only connect via a regular audio cable with an in-line remote.
The wired connection of these headphones has negligible latency which is suitable for gaming and home-theater use.
The Hifiman Sundara are great-sounding headphones with a comfortable but slightly tight fit. They're an excellent choice for critical listening, thanks to their open design and planar magnetic drivers that help deliver a good soundstage, imaging and frequency response. They're also better built than some of the other open over-ears that we've tested and a definite improvement of the HE-400i. However, they can sound a bit sharp on some tracks, and they're only ideal for one use case.
The HiFiMan Ananda are a better critical listening headphone than the HiFiMan Sundara, although not by much. The Ananda have a better overall frequency response that's a bit more balanced than the Sundara. They also have a better soundstage, imaging performance, and harmonic distortion but it's barely noticeable even for trained ears. On the other hand, the Sundara offer a better value for their price to sound quality. They're also a great sounding open-back headphones, with a slightly more compact design than the Ananda that most will prefer. However, they're not the most durable headphones and have a few issues with the drivers.
The Sennheiser HD 800 S are one of the best sounding critical listening headphones that we have tested so far. They have a great build quality and a comfortable design although the ear cup can be a bit large for some. They sound a bit more balanced than the Sundara, especially in the treble range. However, the biggest and most noticeable difference is in soundstage where the HD 800 S feel like you are listening to music in a bigger room than with the Sundara. If your budget is a bit limited, then get the HiFiMan, they're a great alternative to the HD 800 S but won't sound quite as spacious.
The HiFiMan Edition X are also one of the best sounding critical listening headphones that we've tested so far. They have an expertly balanced sound and a better bass performance than the Sundara and the HD 800 S. They're comfortable with large and roomy open ear cups that help create a spacious soundstage that's better than the Sundara and the HE-400i. However, the build quality of their hinges/yokes is not as durable as the Sundara's and the price difference may not be worth it for some.
The HiFiMan HE-400i are good critical listening headphones but do not look or feel quite as premium as the Sundara. They also have a bit less bass and they sound sharper on already bright tracks. They're still one of the better sounding critical listening headphones that we've tested but the Sundara are better balanced and have a sturdier build quality that fixes some of the issues with the hinge/yoke of the HE-400i. If you have the budget, get the Sundara, they are a better-built and better-sounding headphone but they're also more expensive.
The Sennheiser HD 650 are good sounding critical listening headphones but have a mediocre-at-best soundstage. Their sound quality is not as immersive as the Sundara and they can sound a bit too forward with instruments and vocals. However, they do not sound quite as sharp on already bright tracks. Unfortunately, their build quality doesn't feel as premium as the Sundaras and their treble response can be a bit inconsistent at times. On the upside, they are a lot cheaper so if you are on a budget, the HD 650 could be a more affordable alternative to the HiFiMan.