HiFiMan Sundara Review

This entry is part 69 of 73 in the series HeadPhone

The Chinese company claims a decade of planar driver technology development with these robust mid-priced open-backed ’phones – are they a cause for celebration? Read our HiFiMan Sundara Review.

Review: Keith Howard & Christopher Breunig Lab: Keith Howard

Circumaural planar-magnetic headphone Manufactured by: HiFiMan Corporation, Jiangsu Prov., China Supplied by: Signature Audio Systems Telephone: 07738 007776

Web: http://hifiman.com; www.signatureaudiosystems.co.uk

With HiFiMan’s UK distribution now switching to Signature Systems, we are at last able to get our hands on this idiosyncratic range of headphones from China. What makes them idiosyncratic is not merely their use of planar magnetic (aka isodynamic) drive units – something which is becoming increasingly mainstream – but that these drivers are reminiscent of isodynamic units of the past in respect of their low sensitivity. Recent years have seen not just a resurgence in planar magnetic headphones but, thanks to neodymium- iron-boron magnets and the use of finite element analysis to optimise the magnetic design, a notable improvement in their sensitivity. Indeed, the best examples now offer a comparable sensitivity to many moving-coil competitors.


But that certainly isn’t the case with the Sundara, one of HiFiMan’s least expensive ‘Reference’ models, of which there are 17 in total. Its sensitivity is so low, in fact – despite a 37ohm nominal impedance, which is at the low end for medium-impedance headphones – that it’s only right to warn potential buyers that some music sources may not be able to generate sufficient output. Via my (1.4W/ 32ohm) Teac HA-501 headphone amplifier [HFN Apr ’14], not only was the volume control setting much higher than usual, but there was little remaining adjustment once I’d achieved the desired loudness.

It’s only fitting, given this, that the Sundara offers little indication of being intended for use with hand-held music sources, even though HiFiMan does picture it with its own MegaMini hi-res music player [see p71]. At 1.48m in length its cable, which connects separately to each capsule via straight TRS mini-jacks and to

RIGHT: Detachable 1.5m cable locks into place but allows experimentation with aftermarket alternatives. The plastic wrapped earcups are replaceable

the source via a right-angle TRS mini-jack, is a bit too long for convenient use on the hoof. On the other hand it’s also too short for easy use with many a home hi-fi installation, although a clip-on gold-plated 1/4in jack adapter is supplied to aid connectivity in these circumstances. No carrying case is provided and as for the capsules folding up into the headband or anything fancy like that – forget it.

One reason for the Sundara’s low sensitivity is perhaps that – if HiFiMan’s exploded diagram tells true [see inset picture, p69] – it has bar magnets arrayed only on one side of its NSD (NEO ‘supernano’ diaphragm). The advantage of this is that it saves weight, so the headset is relatively light for a planar magnetic headphone at 383g, although this isn’t sufficient to ensure that the Sundara is notably comfortable to wear.

In fact it loses points in longer listening sessions for having round earpads that aren’t quite large enough – they squashed

I was definitely a Pooh child rather than a Mr Toad’

my earlobes – and for having a moderate perceived head clamping force. I say perceived because I measured this at 6.5N (across a default 150mm head width), which isn’t excessive. But it feels distinctly higher than, say, the 5.2N recorded on the same test frame by the Quad ERA-1 [HFN Aug ’18]. That said, the Sundara’s wide headband strap spreads its vertical load sufficiently well across the scalp that even sparsely-thatched pates are unlikely to experience any discomfort. It’s notable, by the way, that some other HiFiMan models – the Ananda and Arya, for instance – use elongated capsule/earpad profiles to reduce any earlobe squashing.

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Like all open-back headphones, the Sundara offers only limited isolation from external sounds. By the same token, it can produce levels of high frequency sound that someone sitting nearby may find annoying. But there are also positives to an open-backed design other than the potential benefits to sound quality of not having a reflective, resonant enclosure behind the diaphragm. Unlike closed- back designs, open-backs are typically pretty relaxed about earpad sealing, losing much less low frequency output if the earpad is less than perfectly sealed to the sides of the listener’s head.

I now supplement our usual frequency response tests, taken ensuring good earpad sealing, with two others in which more normal usage is simulated by using artificial ‘hair’ and a pair of chunky spectacle frames, both compromising the earpad seal. Compared to a typical closed-back design, the Sundara was substantially unaffected by either.

The spectacles didn’t cause significant LF loss until about 30Hz, the ‘hair’ until

50Hz, so the Sundara should deliver similar performance for a wide range of users.

Although tapping the thin steel hoops of the Sundara’s headband elicits a tinny ring, I wasn’t aware of coloration due to headband resonance when listening to pink noise replayed over one capsule, nor of migration of the noise towards the inactive capsule due to headband vibration. So the Sundara avoids the manifest resonance problems we’ve experienced in the past

with similar headband designs in some models [see Investigation, HFN Jul ’16].

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With more or less the same set-up – DNM Series Six preamp for analogue and digital disc sources, and the Mytek Brooklyn DAC/ amp [HFN Aug ’17], fed from a MacBook Pro with the latest

HiFiMan Sundara Review

LEFT: Utilitarian styling and rugged construction. Ratchet height adjustment for comfort is unusually resistant to loosening – a broad leather understrap sits on your head

iteration of Audirvana Plus for downloads – I began [writes CB] where I left off last month with the Focal Stellia headphones. The track was a string quartet arrangement of Jimi Hendrix’s 1967 hit, ‘Purple Haze’, played by the Kronos Quartet [Nonesuch 979 111-1; LP] and recorded in 1985. Then it had me ‘standing up and “conducting”… hard to keep still’.

With the Sundara the overall impression was of mildness, giving rise to a more objective listening experience. The wide soundstage was good and the little dissonances in the two violin parts on the recording registered cleanly, yet there wasn’t a lot of real presence or clout.

I turned to my collection of the Walter (later Wendy) Carlos electronic arrangement LPs as I hadn’t listened to the Bach Third Brandenburg Concerto for years. The album, Switched-On Bach [CBS 63501], had impressed the HFN team in its day (1968) – not surprisingly, since this realisation was consistently inventive.

With the Sundara the music was enjoyable, having good channel separation and clearly focused central information. However, while the overall presentation was very pleasant and tuneful it was also somewhat bland as a quick check with my reference headphones sharply confirmed. There was little real midband richness, while the buzzy distortion in this transcription sounded more like a pick-up mis-tracking on a soiled pressing.

The animal noises on two of my favourite Beatles White Album tracks, ‘Blackbird’ and ‘Piggies’ [EMI PCS 7067/68;

original stereo LPs] registered faithfully along with all the other channel effects.

I listened on through ‘Rocky Raccoon’, where every word was crystal clear. These Sundaras ‘time’ very convincingly, as was confirmed by the drummers spaced extreme left and right on The Allman Brothers’ ‘Black Hearted Woman’ [The Road Goes On Forever compilation; Capricorn Records 2037 101].

Wanting to hear the headphones with pure speech I turned to a well-known voice in the form of Alan Bennett animatedly reading stories in 1984 from AA Milne’s

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The planar magnetic drive unit – comprising a flat ‘voice coil’ laid out on the surface of a thin, flat plastic diaphragm, with bar magnets arrayed close to one or both faces to create a substantially linear magnetic field around the conductors – was patented as long ago as 1961 by Israeli inventors Gamzon and Frei. But as a practicable alternative to the moving-coil driver in headphones it was hobbled in particular by the low-strength magnetic materials of the time. In 1972 Wharfedale introduced the first commercially available planar magnetic headphone – the Isodynamic – but even with samarium cobalt magnets it had a specified sensitivity of just 95dB SPL for 30mW input, equivalent to just 89.4dB for 1V. Planar magnetic technology has come a long way in the interim. KH

House At Pooh Corner [BBC Records REC 493; mono LP] – I was definitely a Pooh child rather than a Mr Toad. With the story of ‘Pooh Sticks’ Bennett’s lower registers were naturally reproduced and there were no problems with sibilants but the voice reproduction was further recessed (regardless of the volume setting) than perhaps it should have been. Furthermore, some of the expressive nuances in the narration were smoothed down. It prompted a return to more adult stuff.

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In Sir Michael Tippett’s score for his Symphony No 3 he suggested miking for the soprano’s vocal interjections in Part 2 to allow them to ride over the orchestra. This is reflected in Hyperion’s new recording with Martyn Brabbins and the BBC Scottish SO [CDA68231/2; 96kHz/ 24-bit download], to be reviewed next month, where some of them are quite stridently demanding of your system and strenuously demanding of the vocalist.

Heard on some headphones the orchestral sound can seem crowded, but the Sundara gave a detailed, wide and deep soundstage presentation with Tippett’s individual scoring – flugelhorn and exotic percussion are both present – boldly present and clear.

The HiFiMan Sundaras are perhaps most convincing with smaller-scale material: solo piano, string quartets, jazz, etc. The very beautiful Melos Quartet recording of Debussy’s one work in that medium sounded quite magical [DG 469 130-2] whereas Karajan’s 1964 La Mer in the same CD compendium

HiFiMan Sundara Review

ABOVE: The Sundara is seen here with HiFiMan’s suggested MegaMini player. Presentation is modest – no carrying case, just ’phones and cable

was exposed as now rather dated in quality. With Maurizio Pollini’s classic version of the three movements from Stravinsky’s Petrouchka, transcribed for piano, and in Prokofiev’s Sonata No 7 the Precipitato finale [DG 447 431-2], the placing of the instrument in the Munich Herkulees-Saal, the subtle dynamic control and impressive concentration in the playing all made a very good case for trying these headphones.

Finally, with the Modern Jazz Quartet’s 1960 studio take on ‘It Don’t Mean A Thing…’ [Pyramid; Atlantic 8 12273679-2], the sense of rapport was palpable as the music went from vibraphone to John Lewis’s extended solo and back again as the track ended. They all seemed to be having a good time!

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8.2 Total Score
HiFiMan Sundara Review

You’d need to try these on for a comfortable fit before parting with your money. And we think the Sundaras are best suited, musically, to listeners who again seek a comfortable experience and would happily forgo the last degree of tonal refinement and dramatic presence. Perhaps geared less to the orchestral or opera enthusiast, for what they accomplish with mainstream rock and pop they offer good value.

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HIFIMAN SUNDARA Over-Ear Full-Size Planar Magnetic Headphones (Black) with High Fidelity Design,Easy...

The Sanskrit word “Sundara” literally means “Beautiful” and this all new Planar Magnetic headphone fits this description in every way. Ultra-fine Diaphragm All New Planar Headphone Inherited from Hi-Fi man’s Advanced Technology Featuring Newly Developed Diaphragm that is 80% Thinner than the HE400 Series Resulting in a Wider Frequency Response, Faster and More Detailed Hybrid Headband Design With the weight spreading strap for outstanding comfort but with a more fashion conscious look with its sleek and sumptuous matte black finish. Form Follows Function With its all metal headband the SUNDARA is built to take the rigors of urban street life. The SUNDARA is as tough as it is beautiful. New 3. 5mm Headphone connector for enhanced durability Pocket Powered Performance The slim line Supermini is the perfect on the partner for the SUNDARA. The Supermini with its abundance of audio power output and the SUNDARA’s grace and poise makes them the velvet glove over a marble fist. Technical...
Last update was on: 2021-01-27 4:00 am
  • Product
  • Features
  • Photos

HIFIMAN SUNDARA Over-ear Full-size Planar Magnetic Headphones with High Fidelity Design Easy...

The Sanskrit word "Sundara" literally means "Beautiful" and this all new Planar Magnetic headphone fits this description in every way.<br />Ultra-fine Diaphragm<br /> <br />All New Planar Headphone Inherited from HIFIMAN's Advanced Technology <br />Featuring Newly Developed Diaphragm that is 80% Thinner than the HE400 Series Resulting in a Wider Frequency Response, Faster and More Detailed<br />Hybrid Headband Design<br />With the weight spreading strap for outstanding comfort but with a more fashion conscious look with its sleek and sumptuous matte black finish.<br />Form Follows Function<br />With its all metal headband the SUNDARA is built to take the rigours of urban street life.The SUNDARA is as tough as it is beautiful.<br />New 3.5mm Headphone connector for enhanced durability<br />Pocket Powered Performance <br />The slimline SuperMini is the perfect on the partner for the SUNDARA. The SuperMini with its abundance of audio power output and the SUNDARA's grace and poise makes them the velvet glove over a marble fist.<br />Technical...
Last update was on: 2021-01-27 4:00 am

Sound Quality: 82%

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As I commented in the main text [p68], the Sundara is unusually insensitive for a modern, medium-impedance headphone. We recorded a voltage sensitivity – averaged for the two capsules – of 105.7dB for 1Vrms input at 1kHz, which is the sort of figure we saw from the first of the new-generation planar magnetic headphones seven years ago [eg the Audeze LCD-2 at 106.0dB; HFN Mar ’13]. Since then we’ve seen a leap in the sensitivity of the most advanced isodynamic designs, to 115.2dB for the Audeze EL-8 open-back [HFN Oct ’15] and 114.6dB for the Oppo PM-2 [HFN Feb ’15]. Being off the pace by 9-10dB is significant.

As we’ve become used to seeing from planar magnetic headphones, the Sundara has a pretty flat response trend below 1kHz [uncorrected responses, Graph 1 below], its output only falling to -6dB (re. 200Hz) below 20Hz. Above 1 kHz the response is also typical of planar magnetic designs in that, while there is a peak in output around 3kHz, there is insufficient lower presence band output generally to deliver what is conventionally considered necessary for a neutral tonal balance. These two features are reflected in the diffuse-field corrected response [green trace, Graph 2] which displays only mild low frequency peaking but a big ‘hole’ in perceived output between 1kHz and 4kHz. Together these suggest that the Sundara will evince a lower-mid and upper-bass warmth accompanied by a softening of the low treble – a view echoed by our reviewer.

Also typical of isodynamic drivers, the Sundara’s impedance is virtually constant, varying by a minuscule 0.4ohm (20Hz-20kHz). So, its frequency response will not be significantly affected by the headphone preamp’s source impedance. However, wiggles in the impedance trace beginning just above 400Hz coincide with irregularities in the frequency responses, suggesting the presence of diaphragm resonances, confirmed by a CSD waterfall which shows high-Q modes particularly in the treble.

ABOVE: The Sundara’s unequalised responses (L/R, grey/red; averaged 3rd-octave, black) show a flat and extended bass but a loss in presence and lower treble

ABOVE: Third-octave freq. resp. (red = Harman corrected; cyan = FF corrected; green = DF corrected)

Sensitivity (SPL at 1kHz for 1Vrms input) 105.7dB
Impedance modulus min/max (20Hz-20kHz) 38.1ohm @ 13.2kHz 38.5ohm @ 4.9kHz
Capsule matching (40Hz-10kHz) ±8.2dB
LF extension (-6dB ref. 200Hz) <20Hz
Distortion 100Hz/1kHz (for 90dB SPL) 0.1% / <0.1%
Weight (headset only) 313g


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