Oppo PM-1 Planar Magnetic Headphone Review
The blu-ray big hitters turn their attention to the headphone market
What is the Oppo PM-1?It seems there is something in the water at the head offices of some of the major headphone manufacturers of late. First I was treated to the mighty Final Hope Pandora VI at £700 complete with Dan Dare styling and fur lined box. Next up came Sennheiser’s phenomenal IE800 - ‘only’ £600 but perhaps the most complete non-moulded earphone on sale today. I thought that after these indulgences, that it would be time for something a little more… puritanical. Instead however, the numbers are climbing even higher. The headphones you see here will set you back a sobering £1,100. Were they from one of the big hitters in the headphone category, they’d still be unusual but given their origin these really are newsworthy.
This is because, the PM-1 is made by Oppo, purveyors of ever more sophisticated and capable Blu ray players - both as Oppo and the engineering behind a number of other manufacturer’s products. Oppo is a big company and their offerings go far beyond Blu ray players and include phones, tablets and televisions. They have up until now shown no interest in headphones though which makes their decision to pitch in at this lofty price point fairly notable. If this wasn’t unusual enough, the PM-1 makes use of technology that has been around since the 1970’s and that represents a considerable engineering challenge to create. This is nothing if not ambitious and suggests that Oppo has some long term intentions in the category rather than simply making a ‘me too’ product. Ambition is one thing, success is quite another though. Can a manufacturer of products that are excellent but have nothing in common with the technology of the PM-1 really challenge the existing order at this exalted price point?
Oppo PM-1 DesignThe PM-1 is a full size over ear headphone which uses an open backed design. Beyond this fairly conventional basic description lies some distinctively unusual design decisions. The vast bulk of headphones - in fact speakers full stop - use dynamic drivers with a conventional pistonic radiating action. The benefits are simple enough. With so much of the market being this type of speaker, the data on a vast choice of sizes, materials, mounting and placement is easy enough to make use of. There are alternatives however and one of these is the planar magnetic principle.
In essence, a planar magnetic driver is an incredibly thin sheet of transparent film that is moved by a ‘printed’ driver of conductors that are placed across the surface. These conductors can be arranged almost any way that the designer chooses and the result is a driver that has an exceptionally even force applied across the whole radiating area. Furthermore, this driver has virtually no mass - it makes titanium and even beryllium drivers look positively heavyweight. As a result of this, the driver is supremely ‘fast’ - it can change frequency at a rate that leaves a conventional pistonic driver floundering. It is important to note that ‘planar magnetic’ drivers are similar but not identical to electrostatic drivers - these also use a membrane but this is constantly charged with an electric current and moved by altering the voltage on either side of it.
So if these drivers are so wonderful why don’t we see them very much? Well, for starters the size of planar driver needed to generate bass as a conventional loudspeaker is not small. I recently had a pair of Magnepan planar speakers show up for test that were as near as no makes no difference six feet tall - and they were still hardly bass monsters. This is not a problem for headphones but the other big issue of planar drivers is sensitivity. Those printed drivers are considerably less efficient than a dynamic cone and this means that headphones that use planar drivers usually require very powerful headphone amps to drive them. The main proponent of the technology up until now has been American brand HiFiMan who sell an entire range of headphone amps that offer the necessary grunt to make them work.
Oppo also has a dedicated headphone amp in the works that looks seriously impressive but they have taken some care to ensure that the PM-1 is more sensitive than you might expect. The printed driver is arranged in a spiral and placed in a powerful magnetic field to reduce the energy required. They are at least partially successful too. Nobody at Grado is going to be concerned that the PM-1 is going to be more sensitive than their open backed dynamic designs but equally the Oppo can be used quite successfully from the headphone socket of an AV receiver or stereo amplifier. The fitment of a quarter inch jack which can’t be removed does suggest that portable devices might be a bridge too far though.
The PM-1 is largely constructed of metal with a generous helping of leather and it feels excellent to hold in the hand
The headphones that have been built around these drivers are impressive too. The PM-1 has fairly large earpads as an unavoidable result of having a fairly large driver in them but the overall package is reasonably compact. It is also extremely well made. The PM-1 is largely constructed of metal with a generous helping of leather and it feels excellent to hold in the hand. The build is extremely substantial and a great deal of thought has clearly gone into the design. This is reflected in the excellent axial movement of the earpads that ensures a comfortable and well supported fit on a variety of different sized heads. To get the required amount of movement, there is no scope to run the cabling internally so the supplied cable splits and connects to both earpads via mono jacks. I don’t generally find this as comfortable as wiring to a single side but Oppo has done the best job they can in this instance. The cable itself is three metres long which should allow for connection to most devices and there is a space for it in the supplied box.
Ah yes, the box. Included in the asking price of the PM-1 is a sizable polished wooden box for storing your headphones when not in use. It is this box that means that the carton to ship the PM- 1 is not significantly smaller than the one used to move Blu ray players about. The box is well finished and ensures your expensive headphones won’t get dusty when not in use, which is commendable but… let’s just leave it at me saying I’m not keen on the colour or the heavily lacquered finish. The result reminds me of the dashboard of a Nissan Maxima or some other US orientated luxo barge and while almost certainly real wood and probably quite a challenge to make would have looked much better to this pleb if it had been left unlacquered. If you are of the same mind as me though, the good news is that a less expensive PM-2 model is planned that simplifies the materials used, junks the box and saves you a few hundred pounds in the process.
Oppo PM-1 SetupThe PM-1 has mainly been used with my Naim SUPERNAIT 2 integrated amp and ND5 XS and XP5 XS streamer as source with occasional help from my Michell Gyrodec. I have also used them connected to a Cambridge Audio 751R and Arcam airDAC with additional sources coming from a Cambridge Audio 752BD blu ray, Sky HD and Netflix via a Panasonic GT60 plasma. Material has included, lossless and high res FLAC, vinyl, blu ray, broadcast and on demand material and services such as Spotify and Grooveshark.
Oppo PM-1 Sound QualityThe PR for the Oppo is being handled by an organisation that is usually fairly relaxed about how products that they represent are reviewed. This made their insistence that the PM-1 be run for 100 hours before I did any critical listening to them more interesting than instructions I normally receive. Does the PM-1 sound like a bag of spanners out of the box? To be honest, I’ve been so harassed this month that I acquiesced to their demands more out of time pressure than unthinking compliance. I very briefly listened to the Oppo after about ten hours, more to ensure that everything was working correctly and didn’t hear anything terrible but otherwise left them be.
Having completed the run in, the first really noticeable aspect of the PM-1’s performance is that although they are fairly sensitive for a planar headphone, they are still not hugely efficient. The SUPERNAIT 2 has a fairly burly headphone amp and previous headphones I’ve connected to it have been deafening by the time the volume is much past the 10 O’clock position. The PM-1 however sailed past this line in the sand and really only got into its stride beyond 11. Similarly, the Cambridge Audio 751R needed -28dB on the dial to really get the Oppo performing and by way of comparison, -28dB run into speakers via that amp is very loud indeed. If you are looking at the PM-1 and thinking about adapting it down to a 3.5mm jack, don’t - it simply isn’t going to do anything.
If you do have the required output to make the Oppo sing, you can be assured that it most definitely can though. Listening to Hidden Orchestra’s Archipelago on vinyl was an experience that proved beyond reasonable doubt that the PM-1 is a tremendously well sorted headphone. As an open backed design, the presentation is huge with none of the constraint that can affect closed back designs. Into this soundstage is a performance that manages to be accurate and at times extremely revealing but has a tonal sweetness that makes it incredibly easy to lose hours to the PM-1. This was demonstrated perfectly on my first ‘quick’ listen to the Oppo at 10pm which finally came to a close at a little after 2am.
The planar drivers do make themselves felt beyond sensitivity as well. The way that the PM-1 handles transients is almost supernaturally fast. What sounds normal through a dynamic driver headphone before listening to the PM-1 can suddenly seem slightly leaden by comparison. The effect is like having a car with a tractable engine and a really well sorted gearbox. At no stage does it ever seem like the Oppo is anything other than ready to go. There is something about well sorted planar drivers that can be seriously addictive and where the PM-1 stands apart from many of the designs is that the bass performance is good enough to keep them honest against dynamic designs.
the PM-1 is a tremendously well sorted headphone
To be clear, the absolute bass depth of the PM-1 is still perhaps the weakest area of the performance and by that I mean it is only very good instead of utterly exceptional but it has enough depth and enough impact to make bass driven music sound as big and as powerful as it should. Compared to the similarly priced Grado GS1000 which is also open backed but uses dynamic drivers, the Oppo doesn’t have the sheer bass weight of the GS1000 but is never feels anaemic either. Furthermore, once you move up the frequency range, the sheer speed and tonal accuracy of the PM-1 starts to make its presence felt.
A final area where the PM-1 proves excellent is as a late night film and TV device. The space that it can generate means that programs never sound too closed in and although it won’t do explosions with the same aplomb as some immediate rivals, it manages to sound cinematic in a way that most headphones simply don’t. I did very deliberately choose late night as a condition for this though as the Oppo leaks so much noise into the room that they can’t really be used as a means of listening to something while somebody else is in the same room. This is the nature of open back headphones rather than a specific criticism of the PM-1 though.
- Wonderfully real and engaging sound
- Beautifully built
- Extremely comfortabe
- Not very sensitive
- Slightly limited bass response
- Slightly blingy box
Oppo PM-1 Planar Magnetic Headphone ReviewLast month, I attracted the attention of some people when I awarded the Sennheiser IE800 a perfect score. If they are concerned I’m going to do the same thing for the Oppo, they can rest easy - the PM-1 is not perfect and neither does it represent the absolute reference of what is available in that category at that price point. While it misses out on perfection thanks to the slightly limited sensitivity and a little lack of absolute bass weight, this is a still a stunningly good pair of headphones. If you do much of your listening via headphones, own electronics with enough oomph to power them and aren’t too worried about the four figure price tag, the Oppo needs to be on your shortlist.
I do think that the wider achievement of Oppo needs to be taken into account too. I can’t find any real information on how long the PM-1 has been in development but regardless, this is still the first headphone that the company has released (in Europe certainly) and with this first attempt, they’ve come incredibly close to perfection with technology that it famously hard to get right. Anyone who works for an established headphone brand reading this should be doing so with a growing sense of unease. This is because Oppo’s first headphone is amazingly good and if the company decides to develop the PM-1 further in years to come, the results could be astonishing.
Suggested retail price when reviewed: £1,099.00
Ease of Use9
Design and usability8
Value For Money8
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