HiFiMAN presented a new, closed variant of the Sundar headphones with the note Closed-Back. This time the shells are wooden, and the planar drivers are equipped with acoustically neutral magnets.
The open Sundara made a big impression on me. They represent a good value for money, are well made, provide high ergonomics, and sound phenomenal. The sound signature is relatively universal, and the sound is resolving and spacious enough to meet my needs. I even like their design and subdued, matte black colors. Although the Asian manufacturer has recently raised the bar with the Edition XS model, the Sundara is softer in reception and cheaper, so they still defend themselves.
I must admit that I was very interested in the Sundara Closed-Back, because there are so many closed planar headphones on the market, and the open ones require optimal listening conditions to focus on music or feel immersion in games. But my enthusiasm was accompanied by doubts. I wondered if the signature of the open model was preserved, if the sound insulation was satisfactory, and how much the soundstage suffered when the structure was closed. I checked if the Sundara Closed-Back (CB) is still a Sundar and compared it with the open variant (OB) and the dynamic HE-R9.
- symmetrical cable with 3.5 mm plugs (length 150 cm);
- adapter 3.5 mm > 6.35 mm;
- headphone stand.
The last addition surprises, but do not expect miracles. The manufacturer converted the foam mold stabilizing the headphones into a stand and glued an acrylic sheet to its bottom. In the test art, it is heavily scratched, but it’s only a stand, so you can’t see the scratches daily. The accessory is also decorated with an impressively cut logo.
Maybe the tripod won’t be highly durable and won’t impress aesthetes, but it’s still a great idea. Thanks to this, the foam mold for headphones, which would eventually end up in the garbage, potentially gains a second life. I recommend only buying self-adhesive silicone pads so the tripod does not slip on the top of the desk or cabinet.
The Sundara Closed-Back has a lot in common with the open variant of the headphones because a matching headband with a suspended headband is used, and the similarities can also be seen in the construction of the housings. At first glance, they seem to be wood and metal, but this time more plastic is used – the matte black driver chambers with 3.5 mm jacks are no longer aluminum. It is difficult to say whether this is an attempt to save money or a way to slim down the structure. Possibly both.
Beechwood shells attract attention with their shape, speckled texture, and colors. They have been slightly wavy and finished with a colorless varnish, so the wood’s delicate grain and natural color catch the eye. It is a pity that darker wood was not used because the matte black and discreet Sundara OB look more universal. However, over time, the Sundara CB convinced me – light wood contrasts nicely with the black headband, and the shape of the shell is not as avant-garde as in the HE-R9 model.
Earmuffs are not surprising. They are again made of soft and smooth artificial leather, uniform on the outside and perforated on the inside. The edges of the pads are trimmed with elastic mesh with a hexagonal structure, and memory foam is inside. However, I noticed that the Sundara CB earmuffs are filled more abundantly than in the open Sundara. Initially, I assumed that the cushions in the open model had already flattened slightly since the test, hence the difference. However, I looked at my photos of the Sundara model and am convinced that the ear cups of the closed variant are thicker, especially in the back part. They are closer to the HE-R9 pads.
The hoops of the headband are already well known, i.e., metal and effectively bent. The fork almost does not move sideways but allows you to rotate the shells vertically and even turn them outwards freely. The size is again adjusted by extending the headband, with nine degrees of adjustment on each side. Under the metal rail of the headband, there was also a classic band made of artificial leather, stitched at the edges. In turn, the black and silver elements of the headband are again plastic – they have a logo on the outside and channel markings on the inside.
The headphones’ build quality is satisfactory, but I was hoping for more. The construction still seems solid because the headband does not creak, and the mechanisms work with a lot of resistance, so the headphones look durable. Again, however, there were some flaws – minor flaws on the plastic parts of the headband, not all the gaps were even, and I noticed a small stain on the wooden shells. However, these are details; you must look closely to notice them. It was no different in the open Sundar or Edition XS case, which is also imperfect.
Ergonomics and use
Great that the hybrid headband has been kept! The manufacturer has recently used headbands without a headband, which, unfortunately, are pretty stiff and can put pressure on the top of the head during longer listening sessions. The band works much better – it is comprehensive and optimally flexible, so it adapts to the shape of the skull. In addition, the size adjustment is optimal; it should cover smaller, medium, and more enormous heads, which is a problem with, for example, the Edition XS, headphones that are large even at the minimum scale.
Closed Sundara CB is heavier than the open variant. TheoreticTheoretically difference is insiginsignificante. The headphones gained 60 grams (372 grams vs. 432 grams). The extra grams are felt in practice because the balance is worse due to the protruding shells. Thus, the open Sundars win ergonomics with the closed variant, which is unsurprising. HE-R9 dynamic headphones, with lighter plastic shells that weigh 328 grams, are also more comfortable. However, during listening to the Sundara CB model, I did not feel any discomfort, my neck did not hurt, and the earmuffs quickly covered my auricles and successfully eliminated the pressure of the headband.
There is no doubt that the headphones are a closed design – the environment is muffled. Perfection was lacking because the noise could pierce the ears while listening to calmer music or quieter parts of songs. I was satisfied anyway – nothing bothered me in the home space, and I had no problems focusing on the music, which is not always possible with open Sundays. I also think that the Sundara CB dampens better than the HE-R9 model. The HE-R9’s plastic, thin, hollow ear cups allow more sound to pass through and seem to resonate more, amplifying specific frequencies from the outside.
The cable has been simplified because it resembles the one from the Edition XS model, which means it looks modest. It starts with an angled 3.5 mm plug, is separated by a small splitter, and is topped with two 3.5 mm plugs. So there was a regression compared to the Sundar model because the plugs of the open variant have metal housings that look more solid than the plastic ones from the Sundar CB. However, I would choose a new cable without hesitation because it is much more flexible, fits perfectly, and can be easily rolled up after listening sessions. For comparison, the cable of the open Sundar is stiff, has straw insulation, and springs a lot so that it can irritate.
- construction: closed, circumaural
- transducers: planar
- frequency response: 6Hz-50kHz
- sensitivity: 98 dB
- impedance: 20 ohms
- cable: 2x 3.5 mm > 3.5 mm + 6.35 mm adapter (approx. 150 cm)
- weight: 432g
- Headphones: Audeze LCD-2, Dan Clark Audio Ether 1.1, HiFiMAN Arya V3, Edition XS, HE-R9 and Sundara, Sennheiser HD 6XX
- Sources: FiiO K9 Pro ESS, HiFiMAN EF400, Astell&Kern Kann Max, FiiO M17, M11 Plus ESS, Cayin N3Pro, FiiO BTR7, Qudelix-5K, Cayin RU-6, FiiO KA3
Sundara Closed-Back does not sound like open Sundara or resemble other brand models. Although there are some similarities to the open variant, there are so many differences that the closed Sundars could be called entirely different. It is not a planar equivalent of the bassy and effective HE-R9, with which the Sundars CB have even less familiar. The hero of the test stands out from all the HiFiMAN headphones I tested. However, I do not doubt that these are not headphones for everyone and that much depends on the accompanying equipment – the Sundara CB is a real chameleon.
Sundara Closed-Back – sound signature
The bottom shows off quality, not quantity. The headphones do not favor any subband of the bass – they pull out the sub-bass, transmit a denser mid-range, and a more punctual upper. The low tones, however, have not been strengthened; they do not try to break above the midrange, and they sound pretty flat and punctual. The Sundara CB are undoubtedly not bass headphones, so they may not appeal to people who need a hefty dose of low tones. The technical side makes an impression because the low tones are precise, fast, dynamic, and varied in texture. There is much to admire in jazz, blues, funk, or classical music. Still, the headphones can also cope with rock, metal, or electronics if we accept more references, monitor messages, and have well-recorded albums in our collection. CB Sundars are sensitive to this; they strongly differentiate the mastering quality – if the recordings abound in springy, controlled, detailed bass, this is precisely how they will sound on the closed Sundars. In turn, songs with sloppy, cut, or muddy bass can quickly fall out of the playlist – headphones are pretty ruthless.
The midrange is similar because the range is balanced, close, and natural. It does not lack warmth and colors because the lower midrange plays an important role. The upper one, however, has not been cut out, so the sound is clear, expressive, and outlined. Attention is drawn to the sound’s complex and precisely marked contour – the closed Sundars do not smooth the sound; they are not soft or bland. The resolution is sensational because the instruments are varied, there is no shortage of details, and the message is generally as direct as possible. However, I did not feel overwhelmed; I did not perceive the midrange as aggressive or sharpened because the headphones do not tire. You can also hear this reference in the midrange because the frequency response is balanced and sketchy, which is perfect for music based on live instruments with solid vocals. Headphones can also sound more effective in modern electronics but do not V-knock. Hence they do not sound so entertaining and synthetic. For this reason, the midrange gets along better with classic electronics.
The treble continues the character of the bass and midrange – they are expressive, precise, and direct but … quite gentle for the HiFiMAN. I do not want to be misunderstood; there is no question of darkening or muddying the music, but the frequency range is calmer than usual in the manufacturer’s open headphones. In the treble, those characteristic “peaks” are not audible; it has a reasonably even course and is still freely extended. The treble powerfully illuminates the other ranges, so you should not be afraid of veiling or extinguishing, but the Sundara CB does not sound razor-sharp. Good recordings are still recommended because the headphones will not hide the evident sibilation contained in the recordings and will not calm down too sharp drum cymbals or guitars. We will appreciate good mastering immediately because the drum cymbals will sound metallic and resonant, with no rustling or sparkling. High-pitched vocals will climb freely but won’t become shrill like guitar solos. Brass, however, will be delivered clearly and vibratingly but not screechingly.
The soundstage is vast, which is a positive surprise. Of course, there is no such effect of suspending the instruments in space, this free presentation from open headphones is missing, but the closed Sundars still do not sound tight even with the unsymmetrical cable from the set. This is due to solid channel separation, which enhances the width of the stage. The stage, therefore, has the shape of a horizontal ellipsoid because stereophony takes the lead. Interestingly, this time the height of the stage is in second place because the instruments are strongly differentiated vertically. The depth is less impressive, but there is still a lot going on on the front-back plane – some sounds reach us from the shoulder area, and others seem to resound slightly in front of the face. The contrasting separation of sounds is also noteworthy because the space is heavily aerated. This is partly due to the unaugmented and controlled bass,
Sundara Closed-Back – Comparisons
I received my open Sundaraas headphones sounding quiet, even, natural, transparentuite gentle for HiFiMAN. It turns out that the closed variant generates a deeper sub-bass, has a warmer midrange, and a calmer soprano, which is devoid of this distinctive accent. Because the extreme bands are calmer than those of the Sundar OB, the midrange comes to the fore, which is more, has more complex, more contoured, and outlined character. The same goes for the bass, which is more precise and differentiated in the Sundar CB than the softer and smoother Sundar OB. In my opinion, the closed Sundays bring technical progress; they sound more resolved and precise, they better differentiate the texture of the instruments, and it is easier to capture micro details.
This does not mean, however, that open Sundars no longer have a raison d’être. The older model impresses with the mid-range of the bass, which is somehow more profound and slightly more massive. The Sundara OBs are also smoother in the midrange, which is not so close, and sound more crystalline in the treble. So the Sundara OB may be better if we prefer a brighter sound with a less accentuated midrange. Open headphones also win with the stage and holography – they suspend the instruments around us, do not seem to limit the space and sound aerated and separated. I consider myself a fan of the open Sundar, but I would choose the secure version without hesitation – the softer, more midrange sound stole my heart. Unfortunately, everything indicates that the closed variant of the headphones will be significantly more expensive – I bet,
And they can confidently compete with them. There are similarities in the bass because both the Edition XS and the Sundara CB go relatively low. However, the closed Sundars sound closer and warmer in the midrange and softer in the treble than the Edition XS. Both models represent a similar technical level, but the Sundara CB is again a bit harder and more contoured – they seem to differentiate the bass or midrange even more, which may be due to the calmer treble. There is so much soprano in the Edition XS that the bass or midrange is less direct, so it’s harder to appreciate them. Naturally, the Sundara CBs lose out on stage, which the Edition XS have impressively large, comprehensive, and accessible. In my opinion, the Edition XS is phenomenal, but … again, I prefer the closed Sundays, mainly for the calmer treble and a more defined contour.
And how does the Sundara CB compare to the closed and dynamic HE-R9? These are entirely different headphones or even their opposite. HE-R9 withdraws the midrange, generates a lot of basses, and sounds impressive. On the other hand, the Sundara CB have calm band extremes and a close midrange, so compared to the HE-R9, they are more natural, technical, and precise. I believe the HE-R9s win in electronics, rap, or popular music, i.e., wherever the bass is essential. Still, they fare worse in lighter genres because the basses or double basses are strangely emphasized. In such a repertoire, the Sundars CB is the top, which seems to be created for live instruments, but with the right path, they are also satisfying in electronics. From me, a point for the Sundar CB is that they are more universal headphones. It is worth knowing, however, that the HE-R9 sounds more spacious and significantly more comprehensive than the closed Sundar, which may be due to the less pronounced midrange.
Sundara Closed-Back – synergy and cabling
Sundara CB does not require perfect synergy because they harmonize with different sources. They also do not need high power because the transducers are low-resistance (20 Ω) and quite effective (98 dB). The headphones, however, are sensitive to the nature of the source so that they can be tuned along the track and quite freely. In addition, the Sundars CB scale with the equipment sounds excellent even with primary devices, but when connected to technically better sources, they gain in dynamics, stage, and resolution.
During the tests, I mainly used two DACs / AMPs, i.e., HiFiMAN EF400 and FiiO K9 Pro ESS. The headphones matched both, but the sound was different – with the EF400, they sounded natural, close in the midrange, and with warmth, and with the K9 Pro ESS, they sounded more impressive, more vital in the band’s extremes, and smoother. Sundara CB presented the differences between the sources at a glance, which is also a good argument for their reference and monitoring character.
It was similar in the case of players – FiiO M15, M17, or Astell&Kern Kann Max sounded completely different. The first (M15) strengthened the bass and calmed the treble; the second (M17) expanded the space and clarified the sound. The last one (Kann Max) provided excellent resolution and an even harder outlined sound. The differences were so significant that the Sundars CB sounded musical with the FiiO M15 and almost analytically with the Kann Max.
I also checked the alternative cable, i.e., a replacement made on the Canare Starquad L-4E5C with an XLR plug. It turned out that the headphones benefit from balanced connections – the stage is broader and deeper, the bass is fuller, and the treble is a bit stronger. I wouldn’t say I liked this last change because the headphones became less pleasant to receive. It may be a matter of the conductor used because other HiFiMANs similarly react to this cable.
HiFiMAN Sundara Closed-Back is an exciting player that is solidly made, looks original, and provides high ergonomics. The headband with a suspended headband is a hit, and the soft earmuffs and wide-size adjustment deserve praise. Even the cable works well because it is flexible and optimally long. I was also not disappointed by the acoustic damping because the headphones allow you to focus on the music even in louder conditions. In turn, the sound is excellent – balanced in every band, unsharpened in the treble, and satisfyingly spacious.
However, it could have been better because of some imperfections and minor visual defects. It is also a pity that the driver chambers are no longer aluminum, which is not visible at first glance. The headphones are also heavier and less balanced than their open predecessor and the dynamic HE-R9.
The headphones cost 400 US dollars. The Polish price of the Sundar Closed-Back is not yet known, but I bet it will be around PLN 2,500. Thus, the new Sundars will compete with the HE-R9 (in the version without the Bluemini adapter) and the Edition XS. I would choose Sundar Closed-Back because they are more versatile than both models, both in terms of sound and usability.
However, the open design does not discourage us if the lowest price is necessary, and we prefer a more transparent sound. It is still worth getting interested in the standard Sundars because these headphones are about PLN 1000 cheaper. However, when we want to switch from them to the closed variant, it should be remembered that there has been significant progress in quality, but the sound has changed.
+ clever stand included
+ strong construction
+ great headband
+ high ergonomics
+ Good sound insulation
+ flexible cable
+ synergy and scaling with hardware
+ balanced and outlined sound
+ wide soundstage
– some visual imperfections
– plastic housings instead of aluminum ones
– average balance