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Accessories Review of Oppo PM-3 planar magnetic portable full size headphones w/lots of pics!!!


Android Expert
Jul 30, 2010
This is a Review of Oppo PM-3 planar magnetic portable closed back headphones. http://oppodigital.com/headphones-pm-3/

I always enjoy reviewing new products that utilize the latest technology trends and find it fascinating when it's released by a newcomer. In my recent review of EL-8C I mentioned how these "young" companies (Audeze, Oppo, Hifiman) became major audio players competing against big audio dinosaurs who have been in business for decades. One of the reasons these companies are in a spotlight because they're pushing boundaries of the technology, exploring new frontiers beyond typical dynamic drivers, and paying close attention not just to a sound but also to a design style. Since I'm partially biased to a portable audio setup, a lot of my headphone reviews are focused on IEMs or closed back full size. But the ability to pack a technology of planar magnetic transducers (drivers) in a portable full size closed back design is something that definitely fascinates me. Though relative to their LCD series, EL-8C was more portable, I didn't find it portable enough for a mobile use. So when an opportunity presented itself, I was very excited to review the latest Oppo PM-3 headphones and their HA-2 portable amp. I felt in love with this dynamic duo right from the start even before receiving these products (from the pictures alone), and this feeling hasn't changed after spending over a week testing them. Here is more to explain my infatuation.

Those who follow high end A/V products are probably familiar with Oppo's popular Blu-Ray players, first released a little over 5 years ago. Otherwise, I'm sure a lot of you have heard about their Smartphones that generated a lot of buzz in the last few years. The birth of their high end headphones and amps happened only a year ago, and their maturity went from 0 to 60 in a record time. In my opinion, this is not a coincidence. A company that perfected the technology of A/V hardware will know a thing or two about sound quality, and being at the cutting edge of smartphone business - you will know for sure how to make a portable audio solution, clearly seen in the design and the functionality of PM-3 and HA-2. As a matter of fact, I couldn't help but to wishfully hope for Oppo R&D to look into Android based DAP combining HA-2 with a smartphone interface. I guess time will tell, and hopefully at the rate of their new releases we won't have to wait for too long to find out what else Oppo is cooking in their lab, but in a meantime let me start with PM-3 review, and then follow it with a separate HA-2 review.

There is no surprise that PM-3 arrived in an elegant packaging with just a minimalistic name logo of a company on the top - such gift box presentation distinguishes a product and makes you feel like you got something special in the box. You won't find any flashy artwork, or a spec, or a list of accessories, so if you are not familiar with a product, this only enhances a surprise of the unboxing experience . Under the cover of the box, you will find an envelope with documentation and everything else inside of a headphone case wrapped in a protective bag.





Considering PM-3 has a removable cable design, the accessories include 2 sets of cables - 3m extended audio cable and 1.2m portable cable with smartphone controls (compatibility choice of either iOS or Android). Both of the cables are very similar with a slim metal connector housing, a nice strain relief, and a rubbery slim cable jacket/shielding with minimum microphonics. Audio cable also has a threaded end to accommodate the included 1/4" adapter. On the earcup side Oppo made a wise decision to use a standard 3.5mm connector. Though you will need one with a slimmer housing, it shouldn't be a show stopper for many aftermarket cables. As a matter of fact, I tested a few of my upgrade cables and found that sound scales up a bit with a higher quality wires, and I will talk more about it later in a sound analysis section.

Regarding smartphone controls, I received one for Android phone with a single universal control button and a mic. I'm guessing that iPhone version will probably have a volume control which is not compatible with Android, but universal control button should work with any phone for Play/Pause/Call with a single click and Skip with multi-clicks. The in-line remote was placed close enough to the face for a better voice pickup during calls. I did like its sturdy plastic design with a metal button in the middle which is easy to find by sliding a finger across concave side of the remote. All these little details make one big difference in how enjoyable it was to use these headphones, and undeniably everything about PM-3 is full of such details.

But without a doubt a "star" of accessories in here is the case!!! Portable headphone is meant to be transported and could sustain damage if not adequately protected. Why so many companies ignore this fact and include a draw string pouch to protect their products is beyond me. I raise this question in a lot of my reviews, and always mention that consumers would even buy a form fitted case as an add-on accessory. Here, Oppo included a hard shell zippered case, made with a fancy Selvedge Denim and a little handle to carry it in style. Inside, the case is lined with a soft material and has an insert (held with velcro side) with a little separator to keep headphones/earpads from rubbing against each other. Of course, the ability of PM-3 earcups to swing 180-deg helps to maintain a flat storage and even allows a little space for a cable inside of the case. Headphone itself has to be stored flat with a cable removed, and the included cable pouch is very convenient to store both cables.









When it comes to a planar magnetic technology used in PM-3, the idea of multi-layer diaphragm with spiral pattern conductors and neodymium magnets is a mouthful that can make you think there is no way it could be fitted in a lightweight portable design, but it actually is. Based on a design of their flagship open back PM-1 headphones, the diaphragm is very thin and ultra lightweight where along with PEM-optimized neodymium magnets Oppo was able to reduce the weight of the transducers while still maintaining a high level of sound quality. In combination with metal/plastic housing and use of artificial leather material, the final weight without a cable is down to 320g - evenly distributed thanks to a balanced design and a comfortable fitment with a perfect clamping force (the first time where I didn't have to use my kids soccer ball to stretch the headband).

Starting with headband, it's leather wrapped with a nice soft cushioning on the inner side which comfortably rests on top of your head. The height adjustment has a nice click mechanism and expandable steel part of the band attaches to a uniquely shaped yoke connected to earcups that swing full 180-degrees. One interesting detail I noticed, inside of yoke there was 2 tiny rubber feet/stoppers to prevent tilting earcups from touching the alloy metal frame. Also, the left end piece where yoke is attached to the headband had a little id bump underneath of clearly labeled "L" so you can easily determine a correct side even in the dark by sliding a finger. The same Left earcup also houses 3.5mm headphone jack.

Earpads are soft and plush with an opening large enough to comfortable fit my medium/average size ears without actually touching the driver. Of course, fitment will differ for people with bigger ears or larger size head, but I was pleased with a fitment and was able to achieve a good seal and a decent isolation despite an even thickness of earpads. With some headphones you do need angled earpads to achieve a good level of seal, while here it worked perfectly as is. As a matter of fact, even so they had an artificial leather material, my ears never got hot or sweaty ever after hours of continuous use.














As I mentioned in my EL-8C review, the principle behind planar magnetic design has been around for over 40 years under different names, but due to a progress in research and development to make it more lightweight and efficient, we are seeing more releases utilizing this fascinating technology. Nevertheless, I still recommend to read Tyll's article about the history and the background of planar magnetic drivers: http://www.innerfidelity.com/content/how-planar-magnetic-headphones-work#kbqmeSG6IEbqKEBw.97. Also, Oppo product page has a lot of interesting info if you want to get more into the details of the technology behind the design: http://oppodigital.com/headphones-pm-3/

Before my sound evaluation of PM-3, I put these headphones through 100+ hours of standalone burn in to condition drivers to their full potential, though to my surprise the change only affected the low end of the spectrum while mids/treble remained the same. Still, I'm a strong believer in standalone burn in to avoid a brain burn-in when you listen out of the box. The next observation came about source dependency and how PM-3 pairs up with DAPs, laptop, and my smartphone. Yes, PM-3 has 26 ohm nominal impedance and efficient 102 dB sensitivity, but I found a sound to scale up not only with a volume but also with a driving power. When I say "scale up", I really mean the clarity of upper mids and lower treble. There is no problem driving PM-3 loud with a portable source, but if you want to have a better retrieval of details - you need to juice them up with extra power.

As an example, I had no problem driving PM-3 with my Galaxy Note 4, and bass had a great slam, but mids were slightly veiled. Pairing it up with HA-2 took a sound to a whole new level! With AK120ii bass quality and extension improved, and mids became clear but not as detailed, more on a smoother side. The same with Fiio X5ii and Cayin N6 in low gain setting, but in high gain they scaled up very nicely with a noticeable improvement in detail retrieval. QLS QA360 pair up was a notch above everything else with an articulate low end and detailed organic mids and even improved airiness in treble. N6 in high gain came very close to that as well.

Cable "rolling" was another source of sound improvement. Stock cable yields a deep low end, clear mids (baseline clarity), and slightly rolled off treble (lacks air). Switching to ASEN OFC cable (it has a slim connector extension), I hear a touch less sub-bass, and a little smoother mids. Next, with Lunashops slim connector silver-plated cable I also found a touch less sub-bass, mids being a little brighter but at the same time loosing a little details. The most significant improvement was with Linum cable using a short (0.8m) interconnect I had for test purpose - a very articulate tight bass response, a detailed bright mids, and a treble that came out to play! I wanted to try my Pure silver cable as well, but the connector was not slim enough.

Going back to a stock cable and using QA360 as my source, I hear PM-3 sound as neutral-smooth with a warm detailed signature. These headphones have an excellent low end extension, organic smooth mids with a great retrieval of details, and a nice smooth treble with a slight roll off. All this makes a perfect combination of clear detailed sound wrapped in warm smooth blanket.

In more details, low end is rather articulate with an excellent extension down to a delicately textured sub-bass rumble underneath of a slightly enhanced mid-bass hump. Mid-bass has an average speed (not too aggressive, but also not too slow), and an average decay. Bass is not super tight, but it's well controlled without spilling into lower mids.

Lower mids have a nice full body, contributing to organic nature of the sound. Upper mids are smooth, clear, detailed - there is no artificial brightness or harsh peaks, and a sound is very natural, but not super detailed. Both female and male vocals are organic and smooth, detailed, and at the same time a little laidback.

Treble is also smooth, detailed, not as extended (a little bit rolled off), but still with enough clarity to give a good sound definition. There is not as much airiness or crispy edge, so it's perfect for non-fatigue extended listening.

Soundstage has an average width and depth, not super spacious, thus creating a more intimate slightly expanded feeling which is pretty good for closed back headphones. Despite this staging intimacy, the positioning and imaging is actually not bad; not exactly 3D, but convincing enough to envision accurate placement of instruments. Due to a warmer smoother nature of a sound, instruments and vocals separation is just average. I mean, you can easily distinguish instruments and vocals, but the layering effect is not as clear as in some bright sound signature headphones.

Since my exposure to planar magnetic drivers started with Audeze EL-8C headphones, they would be my first comparison example. As a matter of fact, I got quite a few requests asking me about this comparison since both headphones are closed back and intended for a portable/mobile use. Here in more details how they stack up against each other.


PM-3 vs EL-8C: EL sound is brighter and has less body; bass is more neutral in comparison, lower mids are a lot thinner and upper mids are more detailed and brighter, treble is crispier and more extended. Sound has more airiness and slightly bigger soundstage in both width/depth, while PM-3 feels more intimate in comparison. So the biggest difference is EL being brighter, thinner, more analytical, and slightly more spacious while PM-3 is being warmer, more natural/organic, smoother, and more intimate. PM-3 is more portable since it's lighter, smaller, easier to wear outside. Both have the same level of passive noise isolation. Also, a standard 3.5mm removable cable is a big plus for PM-3. Furthermore, from a pricing perspective, PM-3 + HA-2 combined in price equal to EL-8C. In my opinion, these headphones don't really compete, but rather compliment each other with their differences. The only thing they have in common is planar magnetic drivers and closed back design, and a preference for either high-gain DAP setting or external amping. Everything else is distinct to help you make a decision based on your sound preference and your intended application.

Comparing to some of the other headphones I have or tested in the past, here is what I found.

PM-3 vs MH40: MH40 bass is slower and not as articulate, it doesn't have the same sub-bass extension, lower mids are a touch thinner and upper mids sounds a bit hollow and a little artificial (in comparison) with less details and clarity, while treble is very similar. MH40 staging has more depth, but overall sound is more veiled and not as refined. Earcups are shallow and not as comfortable. Both have a unique luxurious design, but MH is definitely heavier. MH is not as picky about the source or the driving power.

PM-3 vs B&W P7: P7 has a stronger mid-bass hump which can overpower the sound, lower mids are similar but upper mids sounds a little more colored and less natural, and also treble has a better extension, but it could get a bit crunchy. Soundstage is similar, on a more intimate average level. Both have an excellent build quality with luxurious looks and materials, though I prefer a standard 3.5mm headphone connector vs proprietary 2.5mm under the cup in P7. Furthermore, PM-3 has a more comfortable fitment with a more relaxed (without sacrificing isolation) clamping force. P7 is not as picky about the source or the driving power.

PM-3 vs ATH-MSR7: MSR7 low end has a similar sub-/mid-bass balance but quantity is scaled down. Also, low end is not as articulate. Lower mids are thinner and upper mids are brighter and a little more detailed, though can get a bit harsher. Treble has a much better extension. Staging width/depth are a little better, but overall sound is thinner and less organic, while PM-3 is smoother and with a fuller body. MSR7 is very efficient, easy to drive, and not as picky about the source.

PM-3 vs W60: I know, I'm comparing IEMs to a full size HP, but I just had to add this one for a comparison due to Westone's smooth/warm signature. W60 has a very similar low end, and even some similarities in lower mids as well as treble extension where it also lacks airiness. The difference is in upper mids where W60 is slightly recessed, a little less detailed, and a little smoother. W60 also has a slightly wider/deeper soundstage. Both are picky about the source, though W60 doesn't require any amping.

I already mentioned that I found planar magnetic drivers to require some extra power in order to shine, something that not every source can provide on its own. Thus, here are some of the results testing PM-3 with different portable amplifiers and using Cayin N6 LO as a source.

With Cayin C5 (in low gain): excellent pair up, deep articulate bass, more clarity/details in mids, a little more airiness in treble, soundstage gets more 3D with improved width and depth, also I noticed an improvement in sound separation and imaging.

With FiiO E12A (in low gain): very similar improvement as with C5 (more articulate bass, more clarity and better retrieval of details), but soundstage is not as wide/deep as C5.

With Oppo HA-2 (in low gain): in this pair up the bass doesn't get deeper but becomes tighter and more articulate with a better definition. Mids are more detailed but still remain smooth, treble extension improves and you get more airiness.

In a summary, I like HA-2 pair up better because it doesn't affect sub-bass as much, tightens the bass overall, improves retrieval of details without making sound brighter or harsher. But it can't match C5 soundstage expansion.

With Note 4 vs Note 4/HA-2: HA-2 helps bass to become more articulate, tighter, faster/punchier, mids are clearer and more detailed, and even treble extension improves, becoming more airy.


To say that I was impressed with PM-3 would be an understatement. Everything from a design to a comfort of fitment and its smooth neutral signature put a checkmark next to my headphone requirements. At the same time, it wasn't 100% perfect since connecting it directly to my laptop or my smartphone didn't bring their sound to a full potential and required usb DAC to kick it up a notch in order to bring out more details of upper mids. With majority of my DAPs, either with high power output or using high-gain setting, it was just a pleasure to use PM-3 in a portable on-the-go setup. But in general, it's not just a design and a sound that makes PM-3 so attractive, it's actually their pricing which puts them in a category with a lot of other dynamic headphones where Oppo definitely stands out from a crowd against most of it competition. For a portable (closed back) use, these are the most affordable full size headphones utilizing the cutting edge of planar magnetic driver design, and paired up with Oppo HA-2 portable headphone amplifier - this becomes one serious portable listening combo that can go head-to-head with a more expensive competition, as long as neutral-smooth sound signature with a great detail retrieval is your cup of tea!
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After my review of Oppo PM-3 planar magnetic headphones, I discovered that headphone jack in the left earcup is balanced wired, despite the included single ended cables. That was actually a very interesting find, meaning PM-3 can be driven from various DAPs that support either 3.5mm TRRS (HFM wiring) or 2.5mm TRRS (AK wiring). I also confirmed that Oppo used HiFiMAN balanced wiring scheme where HFM (from the tip) is L+, R+, L-, R-, while AK (from the tip) is R-, R+, L+, L-. This means you can use a balanced 3.5mm cable going directly to HiFiMAN daps, like my HM700, or get 3.5mm (HFM) to 2.5mm (AK) adapter with a wire crossover to match the connection between headphones and your source.

While looking for a cable to support TRRS connection, I came across SuperTech 6ft balanced wired cable, available on Amazon for $7.99 HERE. $400 planar magnetic headphones with $8 cable? Yeah, you better believe it!

Arrived in anti-static bag, there is nothing special about the packaging which keep the price down. Cable has a very nice and sturdy construction, though it's a bit stiff due to a thicker shielding. I didn't experience any microphonics what so ever. Cable is terminated by two identical gold plated 3.5mm connectors with a nice looking housing, and extended with a narrow collar to perfectly fit PM-3 headphone socket. The cable length is 6ft (1.8m) which is longer than a typical 4ft (1.2m) cable. It's still acceptable for a portable use and gives you an extra length to use with a desktop equipment.

Unpacking and design details.





When you compare it to PM-3 cable, you can see that a diameter of a stock cable connector housing is nearly the same as a narrow collar of the connector used in their SuperTech cable. As a result it goes in easy and stays secure attached to the earcup.




When I tried using it with HiFiMAN HM700, it worked fine. But due to that DAP being so small and lightweight in comparison to this cable, and since headphone connector is located inconveniently on a side, I ended up pulling the plug out by accident quite a few times. I'm sure it will work better with other HFM DAPs that are bulkier and support 3.5mm balanced connector. Next I decided to move to my 2.5mm AK-wired daps, AK120ii and N5. This connection required an adapter going from HFM 3.5mm to AK 2.5mm, and I contacted Craig @Whiplash Audio with a request for one. This is a review sample, made with TWag v3 wires which in this case an overkill for $8 cable, but you can contacted him and request to use any wires for such custom adapter. Or you can make your own DIY cable adapter.

Whiplash Audio 3.5mm (HFM) to 2.5mm (AK) custom adapter.




The purpose of this exercise was to find out if balanced cable replacement can improve a sound. What I found is that Oppo's stock cable sounds nearly identical to SuperTech cable since both probably use the same type of wires. But once I introduced 2.5mm adapter into the equation - I found a slight improvement in soundstage width and depth. I wouldn't exactly call it a night'n'day change, but you can definitely hear the difference. Also, despite being 3.5mm TRRS wired connector, SuperTech cable works fine with 3.5mm HO ports (FiiO X5ii/X3ii/X1, AK120ii, QLS QA360, and Cayin N5) connected to all of my headphones with removable cables and single ended 3.5mm sockets.


In conclusion, I found SuperTech cable to have a decent build quality, to provide exactly the same sound characteristics as a stock cable, and to be able to wire your PM-3 balanced. Plus, you can use it with any other headphones as a replacement cable. For $7.99 I can definitely recommend this cable!
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Is the stand included? For $399 I think they should include a stand j/k. Great review Twister. Back in the day I splurged for some Sony MDR-V700DJ headphones, they cost just a little less than my Pocket PC. Great sound but I stretched out the cable riding the bus and the swivels kind of wore out after a couple of years of use.
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