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Oppo PM-1 planar magnetic headphone

Oppo PM-1 planar magnetic headphone

Over the past year, giant-killer Oppo has branched out into the world of high-performance headphones and their associated electronics. The company recently launched its performance-minded flagship PM-1 planar magnetic headphone, which will be followed by the PM-2 planar magnetic headphone. Oppo has also recently launched its HA-1 headphone amplifier/DAC. We’ll focus on the PM-1.

The PM-1 features a proprietary planar magnetic driver developed by Igor Levitsky, of BG Radia fame. Levitsky’s credentials as a designer of planar magnetic drivers are impeccable and he has poured everything he knows into PM-1’s design. The PM-1 driver uses an oblong ‘double-sided diaphragm’ and a ‘symmetric push-pull’ configuration, which means conductor traces and magnet arrays are positioned on both sides of the diaphragm.  Moreover, the open-backed PM-1 uses a ‘FEM optimised magnet system’ that incorporates very high-energy Neodymium magnets. The oval-shaped driver diaphragms use a seven-layer membrane with conductors (again, on both sides) arrayed in a spiral pattern. Finally, the drivers are positioned in beefy, aluminium open-back frames and fed by purpose-built signal cables that employ Ohno Continuous Cast (OCC) conductors.

, Oppo PM-1 planar magnetic headphone

The upshot of these design features, Oppo claims, is a driver that is uncommonly efficient (102dB/mW), light and responsive, stable and consistent, resistant to uncontrolled resonance, and reliable. Many of the metal elements of the PM-1 frame, for example, are carefully machined and polished to an Aston Martin-like lustre, while its perforated leather-covered ear pads look like something from a Porsche Design catalogue (though velour-covered pads are also supplied for those who prefer textile materials). The headphones are supplied with two sets of user-replaceable signal cables—one 3m cable terminated with a 6.35mm headphone plug and the other a 1m cable terminated with a 3.5mm mini-jack plug. Packaging is gorgeous as the headphone arrives in a beautiful, lacquered wood presentation case along with and a denim-clad carry case. No doubt about it: Oppo knows how to press all the right pride-of-ownership buttons among prospective PM-1 owners.

 

For our listening tests, I primarily used a Chord Hugo portable amp/DAC and AURALiC’s new GEMINI 2000 headphone amp/DAC/Stand to power the PM-1s, though I did try a handful of smartphone experiments as well. As comparison references, I used Audeze’s LCD-3 and HiFiMAN HE-560 planar magnetic headphones

, Oppo PM-1 planar magnetic headphone

One of the first things veteran headphonistas will notice is the extremely high (102dB) sensitivity of the PM-1s—higher by far than any other planar magnetic design I have evaluated thus far. Quite frankly, the PM-1’s high sensitivity affects nearly every other aspect of its sound and in positive ways. Where many (perhaps most) top-tier headphones are somewhat finicky to drive, Oppo’s PM-1 proves the exception to the rule. It is ridiculously easy to drive and rarely taxes ancillary amplifiers beyond their output limits. In a pinch, one might even drive the PM-1 from a tablet or smartphone, though that would not be the preferred choice for optimal sound quality. I say this because the PM-1 is highly revealing of amplifiers’ qualitative strengths and weaknesses, so that even though the Oppo may not require a high-powered amplifier it does deserve a high-quality one. Even so, the PM-1’s high sensitivity gives owners a greatly expanded range of viable amplification options.

Two sonic benefits of the PM-1’s sensitivity are an expansive, free-breathing quality as it reproduces micro- and macrodynamics in music, plus an unusually lifelike, just-won’t-quit quality of dynamic expressiveness. Contrast this, if you would, to the performance of great but at times demanding headphones such as the Abyss AB-1266, HiFiMAN HE-6, or Sennheiser HD 800s. Those headphones can and sometimes do overtax associated electronics, causing them to sound momentarily flat, quashed, compressed, or worse, ragged and harsh. Happily, those sorts of problems rarely if ever occur with the PM-1. As long as you supply an amp capable of sonic refinement, these headphones will sail merrily along, sounding eminently musical and expressive in the process.

Next, let me draw to your attention the PM-1’s exceptional bass and midrange response. The PM-1 is a superb bass transducer, offering impressive low-frequency depth, power, and pitch definition, with a goodly amount of transient speed thrown into the bargain. The only question I suspect some listeners will ask is whether the PM-1 crosses the line between offering thoroughly adequate low-end output vs. delivering somewhat ‘larger-than-life’ bass. My personal take on this question is that the PM-1 tilts slightly in the latter direction, but only very slightly. One thing is for certain, however, which is that the PM-1 will instantly show you the difference between transducers that mere imply bottom octave output versus those, like the PM-1, that actually deliver the genuine article.

To grasp this last point, try listening to third (Lento) movement of the famous Bakels/Bournemouth performance of Ralph Vaughan Williams’ Symphony No. 7 [Sinfonia antartica, Naxos]. This movement features several sections where listeners will, or at least should, hear deeply descending organ pedal-note passages. As the pitches of those pedal notes plunge ever lower, there is no diminution of power or pitch definition through the Oppos, meaning that the PM-1s can effortlessly take you deep into low bass territory where few headphones and even fewer loudspeakers are able to go. Such is the bass power and articulacy these headphones have on offer.

, Oppo PM-1 planar magnetic headphone

The midrange of the PM-1 is, like its bass response, powerful, smooth, and highly articulate. The only caveat I would offer is that the Oppos did seem to need a good bit of run-in time before their midrange capabilities blossomed fully. Before break-in, the PM-1’s midrange was very good, but sounded just slightly ‘stiff’ or ‘wooden’ and thus lacking to some extent in nuance. But after run-in (about 50 hour’s worth), the PM-1s developed wonderful qualities of quicksilver-like fluidity, transient speed, and—for for want of a better term—suppleness. While the PM-1’s midrange tonal balance, per se, changed very little during run-in, the qualitative aspects of the headphone’s midrange performance became audibly more sophisticated, so that delicate details and subtle points of dynamic emphasis gradually became easier to hear, savour, and appreciate. Nowhere is the headphone’s subtlety and suppleness more obvious than when listening to recordings from talented female vocalists.

 

Consider, for example, the performance of the great British jazz singer Norma Winstone on the track ‘The Mermaid’ from her album Distances [ECM], featuring veteran sidemen Glauco Venier (piano) and Klaus Gesing (clarinet/saxophones).

“The Mermaid” begins with percussive sounds and ‘strummed’ notes played on a prepared piano and their sheer midrange sumptuousness and richness of detail give the song’s introduction a mysteriously engrossing, otherworldly feel. Then, Winstone’s voice appears and its qualities of subtle purity and delicacy of inflection only enhance the dreamlike quality of the piece. Winstone’s voice is a model of deceptive simplicity, purity, and understatement, so that casual listeners might at first think it to be plain or lacking in expression. But the Oppo PM-1s deftly reveals that the opposite is true; like the vocal equivalent of a great watercolour artist, Winstone understands that less is more and that fine textural shadings and the gentlest touches of inflection can carry more impact—and greater soulfulness—than big, bombastic vocal gestures do. 

In terms of bass and midrange performance, the PM-1’s performance arguably equals or surpasses that of far more costly headphones, but how does the PM-1’s upper midrange and treble response fare in comparison to class performance leaders?

, Oppo PM-1 planar magnetic headphone

Taking a glass-half-full view, the upper midrange and treble response of the PM-1 is smooth, articulate, and well detailed—albeit in a somewhat reticent and thus self-effacing manner. Where some headphones impose sonic detail with a capital “D”, rubbing the listener’s face in vast quantities of upper midrange/treble minutia to the exclusion of all else, the PM-1 instead takes a more relaxed (though no less serious) approach to music reproduction. It’s upper mids and highs are never aggressive, never abrasive, and never unduly bright sounding, yet they nevertheless convey many of the subliminal details that add richness and realism. The PM-1’s sonic presentation is generally accurate, but when it errs, it does so in the direction of a gracious and easy-going sort of listenability.

The PM-1 achieves this relaxed sound through a very subtle dip in its upper midrange response, plus a noticeable roll-off in its treble response. These deviations from strict neutrality can undercut two of the qualities many headphone aficionados crave: namely, musical immediacy and intimacy—qualities that some competing headphones deliver in spades.

After doing a side-by-side comparison of Audeze’s LCD-3, HiFiMAN’s new HE-560, and Oppo’s PM-1, both the LCD-3 and the HE-560 offered slight more forward-sound, full-bodied upper midrange response and noticeably flatter and more extended highs than the PM-1. Whether you prefer the Oppo’s richer and more relaxed presentation or the more vivid, airy, and transparent sound of the Audeze and HiFiMAN headphones is for you to decide, but it is important to understand that the PM-1 will force you to make a choice. And what makes that choice even more difficult is the oh-so-seductive quality of the Oppo’s bass and midrange.

 

As we went to press, I learned that Oppo has developed a new set of (optional) ear pads for the PM-1 that are said to help open up its upper midrange/treble response (these same pads will come as standard on Oppo’s PM-2 headphone). Oppo will make these pads available to current and future PM-1 owners. Accordingly, we plan to do a follow-up report  to highlight changes, if any, in the PM-1’s sound.

, Oppo PM-1 planar magnetic headphone

For now, Oppo’s PM-1 stands an impressive entry in a market space where competition is very stiff. I would rate the PM-1 as a world-class bass and midrange transducer—one whose midrange fluidity and suppleness are quite extraordinary. The headphone’s subtly recessed upper mids and slightly rolled-off highs can, however, generate mixed reactions. Some listeners (especially those who favour a sumptuous, rich, and relaxed presentation) will love the sound, while others might wish for something offering greater treble airiness and transparency. Either way, I recommend auditioning the PM-1s before choosing any headphone in this class.

Technical Specifications

Type: Circumaural planar magnetic headphones

Driver complement: Oblong 85 x 69mm planar magnetic drivers with seven-layer diaphragms with spiral-shaped conductor arrays on both sides of the diaphragm, and a ‘symmetric push-pull’ Neodymium magnet system

Frequency response (in Free-Field): 10Hz – 50kHz

Impedance: 32 Ohms

Sensitivity: 102dB/mW

Accessories: Wood presentation case, carry case, two sets of signal cables with OCC conductors (one 1m cable with 3.5mm stereo mini-plug, one 3m cable with 6.35mm stereo headphone plug), spare set of velour covered ear pads.

Weight: 395 grams (without cables)

Price: £1,099

Manufacturer: Oppo Digital

URL: www.oppodigital.com

UK Distributor: Oppo BD UK, Ltd.

URL: www.oppo-bluray.co.uk

Tel: 0845 060 9395 (UK only) or +44 (0)1603 402240

Tags: FEATURED

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