Hifiman Sundara, Arya & HE-R10D

The Sundara is one of the most affordable pairs of open‑backed planar magnetic headphones available.

Hifiman are driving the development of headphone technology at an impressive pace!

Established by Dr Fang Bian and based in Tianjin, China, Hifiman manufacture headphones and in‑ear monitors, along with associated equipment such as DACs and portable digital music players. As the name suggests, their products have historically been targeted at the hi‑fi market. However, it’s not unusual for headphone and speaker manufacturers to cross over into the studio world, and several Hifiman models have become popular choices for recording and mixing. At the time of writing, there are more than 20 pairs of over‑ear headphones in the Hifiman catalogue, ranging in price from the $129 HE400se right up to the $6000 Susvara and beyond.

Planar Potential

The Hifiman range includes conventional moving‑coil and electrostatic designs, but the large majority of their models feature planar magnetic drivers. Like moving‑coil drivers, these are based on the principle of electromagnetic induction, but whereas moving‑coil designs have a moulded, rigid diaphragm with a coil of wire attached, planar magnetic designs use a flat diaphragm with thin wires embedded in it or attached to it.

This is a technology that has some inherent advantages over more traditional designs. Well‑designed planar magnetic headphones can have incredibly low distortion, and their presentation of musical dynamics is second to none, as is their low‑frequency response. Recent technological developments have also mitigated the historic downsides of planar magnetic headphones, such as low sensitivity and poor high‑frequency extension. High‑end planar designs like the Audeze LCD‑X are now well established as monitoring tools in the studio world, but they represent a serious financial investment. Hifiman likewise offer plenty of choice in this high‑end bracket, but their range also makes the same technology available at much lower prices.

Hifiman are also prolific innovators when it comes to headphone design. New and proprietary technologies they’ve developed include an ultra‑lightweight diaphragm material said to be of “nanometre thickness”, allowing their designs to get ever closer to the theoretical ideal of a diaphragm with no mass at all. In a planar magnetic driver, the magnetic field that pushes the diaphragm to and fro is created by having magnets either side of the diaphragm. Hifiman’s Advanced Asymmetrical Planar Driver pioneers the idea of making the magnets on the inside smaller than those on the outside, reducing diffraction and obstruction of sound waves passing from diaphragm to ear. Sound escaping outwards, moreover, can benefit from the patented Window Shade louvre design, which makes the outside of the earcup more open and less reflective. And whereas the earcups on most headphones are symmetrical about both the vertical and the horizontal axes, some Hifiman designs use an asymmetrical cup that is intended to follow the shape of the human ear more accurately.

Going Deep

For this review, I was sent three models from the Hifiman range. Retailing at an extremely competitive $349, the open‑backed Sundara is one of Hifiman’s most affordable and most popular planar magnetic designs. The $1599 Arya, meanwhile, is a more upmarket open‑backed planar magnetic headphone that incorporates all four of the new developments described above. Finally, the HE‑R10 is an intriguing closed‑back design with earcups fashioned from wood. It’s available in both moving‑coil (HE‑R10D) and planar magnetic (HE‑R10P) versions; I tested the former, which retails at $1299.

I suspect that one of the reasons why phones like the LCD‑X sound so great is the use of a very deep cushion around the earcup, which positions the driver quite a bit further from the ear than we’re used to in conventional headphones. This is also a design feature of HEDD Audio’s remarkable HEDDphones and of Avantone’s Planar model, and likewise of all three of the Hifiman models I tested. All three are also supplied in substantial cardboard boxes, with the headphones and their cables nestling in lavish velvet drapery, but without any other sort of bag or case. Beyond this, though, there’s a surprising divergence in the physical design of the three models.

Here Comes The Sundara

The Sundaras are perhaps the most conventional of the three. This model does use symmetrical earcups — in fact, they’re perfectly circular — but the cushions are less deep towards the front, so the cups angle inwards slightly. Connection to the audio source is made by a Y‑cable with TRS mini‑jacks that slide into the base of each earcup. Being only 1.5m long and rather inflexible, this cable isn’t ideal for all situations.

The earcups are mounted on forks which slide into the headband, allowing them to rotate up and down but not sideways, while a wide leather strap spreads the load on the top of the head. At 372g the Sundara are not as heavy as some planar magnetic designs, and I found them generally comfortable. Both frame and earcups are made mainly of metal and give the impression of being robust. Hifiman’s specifications claim a truly heroic frequency response of 6Hz to 75kHz, though no tolerances are quoted. The nominal impedance is 37Ω and sensitivity is given as 94dB.

The Arya’s distinctive earcup is non‑symmetrical and designed to follow the contours of the ear.Apart from the logo, the overall black colour and some basic design features that are common to almost all headphones, the Arya are different from the Sundara in almost every respect. The earcups are deeply elongated and also slightly asymmetrical front to back, with the distinctive Window Shade slats in place of the Sundara’s wire grille. The cushions are once again tapered, but are slightly deeper and faced with what seems to be real rather than synthetic leather. The earcups are attached to a different fork system which, this time, is also hinged at the point where it joins the frame, allowing front‑to‑back rotation; and this time around, it’s the headstrap itself that adjusts to achieve a comfortable fit. Even the cable is different, employing “crystalline copper” wire with a more flexible braided coating and a fixed quarter‑inch jack at the other end. (The supplied cable did not work, though, so I tested the Arya with the Sundara cable.)

I don’t think anyone will be terribly disappointed to learn that the Arya’s published frequency response is slightly narrower than that of the Sundara, at 8Hz to 65kHz, though again, no tolerances are given. Impedance is listed as 35Ω and sensitivity at 90dB. The Aryas are also marginally heavier than their siblings, weighing in at 404g, but once again the soft cushions and broad headstrap make them sufficiently comfortable for long sessions. In practice, although both the Arya and the Sundara are less sensitive than typical moving‑coil models, I had no problem driving them loud from a good‑quality audio interface headphone socket.

Into The Wood

Both the Sundara and the Arya are, if not exactly conventional, at least obviously recognisable as headphones. By contrast, the HE‑R10Ds are truly extraordinary — and, once again, almost entirely different. I’m not sure to what extent the use of wood as an earcup material is driven by considerations of performance or appearance, but it’s certainly striking. The wood has an attractive figure and a bold orange tint, the cups are shaped smoothly and attractively, and despite being the bulkiest of the three models on test, the HE‑R10Ds are also the lightest at 333g.

Wood you believe it: the HE‑R10 is unusual to say the least!The ear cushions this time form a shallow oval, once again slightly angled inwards at the front, and yet another different fork design permits a small degree of forward/back movement. There is no separate headstrap as on the other models, but achieving a comfortable fit is just as easy. Just for variety, the HE‑R10Ds connect to the outside world via a single mini‑jack socket in the base of the left earcup. No fewer than three cables are supplied, all apparently of high quality and terminating respectively in a mini‑jack, full‑size jack and four‑pin XLR. You can also replace the cable with a miniature DAC called the Bluemini, which attaches directly to the mini‑jack socket and receives audio over either USB or Bluetooth.

The drivers employed in the HE‑R10D introduce another Hifiman technological innovation called the Topology Diaphragm. As far as I can understand, this involves applying a special coating to the surface of the diaphragm to control its texture. As you’d expect from a moving‑coil design, the HE‑R10D is more sensitive than the other models, achieving a specified figure of 103dB with a quoted impedance of 32Ω. It also has a slightly more curtailed frequency response, though since this is still given as 15Hz to 35kHz, this is unlikely to be a problem.

Listening Tests

Given how different the review headphones are in other respects, it was something of a relief to discover that the Sundara and the Arya actually have quite a bit in common sonically. My impression in both cases was that Hifiman have put a lot of effort into overcoming the subdued treble response that is a shortcoming of traditional planar magnetic designs. Compared with the classic LCD sound, both display a noticeable presence rise in the upper mids. In principle this is no bad thing; neutrality is both a moving target and a highly subjective goal in headphone design, and one person’s uncoloured response may well be another person’s dull or soft.

Both models also inherit other key strengths of planar magnetic phones. Musical dynamics are put across with real force and power, and I was particularly impressed with the stereo imaging. Obviously, headphone stereo will never sound like loudspeaker stereo, but these headphones provide a convincing sense of width, and make it easy to locate individual sources within the panorama. And these two models both have the sense of clarity and endless transient headroom that I associate with really good planar phones.

One of the other things that’s so remarkable about the Audeze phones is the low end. Bass instruments have a sense of articulation, depth and balance that you simply don’t get from most moving‑coil headphones. The low end is less prominent on the Sundara and Arya, and indeed the bottom octave or two sound a little shy to my ears. However, there’s no doubt the information is there, and some brief experiments with EQ suggested that it should be possible to restore a weightier balance if that’s what you like.

Inasmuch as I have reservations about the sound of these two models, then, they’re really to do with that presence boost in the upper mids. As I already mentioned, the additional brightness compared to some other phones is not unwelcome in principle, but in order to be benign, this sort of treble lift needs to be broad and even, and I couldn’t quite convince myself that this was the case here. The Aryas, in particular, have quite a noticeable peak in the 4kHz region, which can cause some sounds to jump out of the mix in a rather unnatural way. I would hope this could be tamed by corrective EQ, but Sonarworks don’t currently have a generic profile for this model, so I wasn’t able to confirm this.

What then of the HE‑R10D? Once again, there’s also something of an emphasis on the upper part of the mid‑range, making the overall sound a little ‘scooped’ and soft in the 1‑2 kHz area. I’m not sure what sonic benefits the wooden earcups provide, but they offer somewhat less isolation than a conventional closed‑back design, and are a little prone to amplifying mechanical noise. The most noticeable feature of these phones, though, is the bass. It’s anything but shy, and is especially prominent in the 100‑150 Hz region. This takes some getting used to, but I can imagine it proving useful in genres that require a particular focus on the low end.

I can believe that there’s a Hifiman model to suit everyone — it’s just a question of finding it!

Hi Fliers?

Even having tried three different models, then, I’m reluctant to draw any universal conclusions about Hifiman headphones. Whereas other manufacturers’ product ranges typically share many design elements and a have ‘family sound’, that just doesn’t seem to be the case here. I can believe that there’s a Hifiman model to suit everyone — it’s just a question of finding it! Stylish and unique though they are, I’m not sure I see an obvious role for the HE‑R10D in a music production context, unless you find that an epic low end helps you get into the creative zone; certainly, I’ve heard conventional moving‑coil headphones that sound closer to my perception of a neutral sound at a lower cost.

By contrast, the Aryas certainly do have the potential to be a very capable mixing tool. Achieving such an extended and present high‑frequency response from a planar magnetic driver is no easy feat, and I can’t think of another planar model I’ve tried that comes close. To my mind, however, they probably require some form of software equalisation to fully realise their potential. In their raw state, that 4kHz peak gives the sound a slight standing‑in‑front‑of‑a‑Fender‑Twin quality that gets tiring fairly quickly. They are also pitched price‑wise against impressive competitors, such as the various Audeze LCD models, Focal Clear MG Professional, Sennheiser HD800, AKG K812 and HEDD Audio HEDDphones. As always when there’s this much money involved, I’d recommend extensive auditioning before you make a choice.

Out of the three models on test, then, I’d have to say that the relatively humble Sundaras are the ones that really hit the sweet spot for studio use. I’ve heard the combination of good planar magnetic drivers and big, deep earcups enough times by now to be convinced that it delivers a distinctive quality which is both useful for mixing and hard to get from other designs. Until now, the Avantone Planars represented the most affordable way to get that quality, but these are significantly more affordable. Both represent excellent value, and those who prefer a crisper tonality won’t regret choosing the Sundara.