OPPO PM-3

Main reason that I bought the pair was the very low THD figures in audiosciencereview review. Usually, the THD in bass is pretty high and will go even higher if you listen loud.
For example, on something like Senheiser HD5xx or HD6xx, I can hear the distorsion if I listen to loud levels.
If I am to boost the bass on the above mentioned (as both lack sub-bass), the distorsion would become audible even
earlier. And on those even at medium levels, the bass in not as clean as on the Oppo PM-3.

Initially my expectations were very high in regard to this headphone.
Most reviews said they're very easy to drive and sound fantastic. While they do sound fantastic (with EQ), they're certainly not very easy to drive as you will see below.

HOW EASY THEY ARE TO DRIVE:
For me, easy to drive means they can be driven at fairly loud levels from pretty much anything, including a phone/dongle.
That is clearly not the case: these pair will require a fair amount of power to be driven loud. And while they can be driven at low to moderate volumes by pretty much everything, you will definetely need a DAC/amp for these if you want to go above moderate SPL levels.
While there are headphones that are much harder to drive out there (like the 120Ω HD560S, the 300Ω HD6xx and the 470Ω AudioTechnica R-70x among others), something like the SONY MDR-1AM2 is significantly easier to drive. That's why I want to put this in context.
That said, most DAC/amps and DAPs with decent power output (like 200mW RMS or more) will be able to drive these without an issue.

COMFORT:
Despite the PM3 have a pretty high clamp force, they're very comfortable and can be worn for many hours without fatigue.
The original leather is very breatheable, you won't get hot or sweat unless the environment is very hot.
One of the best leather ones that I've tried, however there's also a big downside to this: genuine pads are very expensive to buy (if you can find them at all), while the headband itself cannot be found.
The headband can be repaired with the right materials as it's only clipped on (I have the limited edition version). When I will repair it, I intend to replace the material with something velour-like which will last a lot longer.
Problem is velour will be of a different color, typically black so you will have to accept the looks as they are.
When buying these, do keep in mind that leather will wear sooner or later and you will have to find a replacement.
I have ordered a pair of black velour pads for future use, but they have not arrived yet. I will update the review if I find those pads to be a suitable replacement for my taste. Velour pads will likely attenuate the bass, requiring less EQ.
Also do keep in mind that most aftermarket pads are not as high quality as the original.
This is by far the biggest disadvantage of the Oppo PM3.

SOUND QUALITY:
The sound quality on these is exceptional: they sound good and clean even without EQ, but depending on how certain tracks are mastered you will hear too much boomines (due to very elevated upper bass) and a bit muffled lower treble.
To my ears they sound the best when you apply EQ to them, as this way you will benefit from both a very low THD and a frequency response that's very very close to the Harman curve.
Overall I would rate the sound quality a 5/5 with EQ and a 4/5 without EQ. This means that while it can be used without EQ and it can even be beneficial on tracks that have less bass than normal due to poor mastering, using EQ will make this headphone sound neutral and without any coloration.
Contrary to what another review has said, this headphones are not neutral without EQ: the upper bass is quite too boomy,
while the lower treble does sound a bit muffled (both show up on measurements).

It is also to be mentioned that neutral ≠ flat frequency response. Neutral means that the frequency response that we perceive audibly is flat and that is obtained by the Harman curve (which is not flat) because the head transfer function
is not a linear one.

Overall, this is one of my favourite pair of closed-backs due to very good comfort combined with top sound quality and a relatively standard cable. The big downside is these are no longer made and aftermarket pads are not of the same quality. Given these have quite a following, maybe we'll see better pads and even headbands in the future.
I recommend getting the Oppo PM-3 if you have no problem with using EQ and if you find a pair that has the original leather still in good condition. Then be prepared to replace pads and repair the headband.

About myself

I'm 38, so my hearing is possibly not the same as in my 20s. I like various music genres, mainly prog rock/metal, blues and some classical music. I'm not into rap/hiphop/EDM so I don't have a strong preference regarding excessive bass quantity.

Some background

I've purchased this item myself, it was used. I have no affiliation with the manufacturer nor was this a sponsored review of part of a loan tour.

Unboxing

Unboxing is a pleasant experience, the box is stylish just as the carrying case. There are a lot of cable options (without mic, with mic: Android/iOS).

Comfort and fit

I found this very comfortable. I have average sized ears and the fit was good. However, the earcups are small so it may not be suitable for people with big ears.



Sound

I very much liked the sound, but I think it can be further enhanced with some EQ.

The bass quantity is sufficient, and quality is great. Does not bleed into the mids.

Mids are detailed, engaging and emotional.

Treble is a bit veiled, it rolls off a bit. This can be corrected with some EQ a lot.

Overall, I find the tonal balance pretty good, it is fun to listen to these headphones. Detail retrieval is good enough.



Comparisons

I found the Shure 840 more linear, and bit more detailed. However, the Shure was not designed with portability or syle in mind, that is for s(h)ure



Sources

Very easy to drive, but to get the best sound out of it, make sure to use a headphone amp. At least an USB dongle, like the E1DA 9038D.



Conclusion

I loved this headphone, but I prefer transparent, extra detailed sound. If that is your preference too, then there are better alternatives than the Oppo PM-3. However, this is a wonderful headphone suitable for portable use.

I just picked up a set of PM-3's about a week and a half ago. Actually, the pair I'm using isn't mine, but the store owner tossed me the demo to use while I wait for my brand new set to come in. This is my first venture into planar magnetic. I was looking at the PM-2, but he wouldn't budge on the price much considering they are discontinued and the one set he had was a demo. I also heard the PM-2 are nowhere near the PM-1, and open back did concern me for listening at home (mom nagging because I do listen to music quite loud). I went into this set expecting a closed in sound, as magic is not real and one can not produce an open sound without some sort of back venting.

What first drew me to these phones, apart from being planars, was the impeccable quality and looks. I know know there is no leather on them, but the faux leather is of a better quality than real leather on other phones. When I slipped them on in the store, I felt immediately comfortable, no clamping, yet the outside world is blocked out. Some have stated they get hot wearing for long periods, but I've listened to them outside at work for 30 minutes in 30 degrees Celsius and have no complaints. The rest of of the cans look sturdy, well designed and...well essentially a Chinese company showing it can kick the quality of other manufacturers who have their stuff built in China. Now I'm not a lover of Chinese stuff, but I firmly believe manufacturers put effort into their stuff when it is made where the company is located.

Setup: I have been using an iPod with FIIO amps since I began getting into higher end portable audio. Currently I'm using a FIIO E12, and a 30 pin to lightning DAC adapter to my iPod. I hope to eventually get a DAC that works with OTG from my LG G5, but the E12 (and whatever the colorizing of sound it does) is my standard for now. Much of my music is lossless, a lot of it 16/44.1 or 24/44.1. There are a few 320 quality mp3 songs. My main listening includes jazz classics (Paul Desmond, Oscar Peterson, Miles Davis, etc), some more modern jazz and funk, classical, classic rock, classic pop, and 90s and early 2000's hip-hop/ rap. There is also some metal in there like Rammstein, and some celtic music, ranging from pure bagpipes, to celtic rock.

Bass: The bass on the PM-3's is somewhat strange. They clearly aren't a bass headphone, but they are capable of massive (to me) bass. With classical music, jazz and most rock, I find bass full and proper, not bloated, but there is the odd song where I feel the need for bass gain to be used on the E12. Now...put on Wiz Khalifa On My Level, and these cans rumble. There is no distortion even with this level of bass, and they extend below audible bass levels, to the points where you hear nothing for the most part, but feel the drivers going. Now, I'm no basshead, apart from the odd tune here and there, but the PM-3 surprise me a lot. On first listen, one would expect neutral, light bass, and with other similar signature phones, you can hear them fall apart when pushed. The PM-3 however, they can dish out what you want.

Mids: The mids on the PM-3 are extremely clear and detailed, to the point where breathing comes through, or even quiet background noises. The soundstage is the only thing that hurts the mids a tad, but the soundstage is about as good as it gets for closed back. I found the mids to be really present in the Bach Cello Suites, where every note sounded with power, yet every note rang distinct. With the business of many parts of the cello, such clear sound is not easily produced in other headphones that I have.

Highs: The highs are very clear, although slightly laid back on these headphones. I believe my E12 does have a warmer amping, or at least I've read it does, so this may be causing the highs to be recessed more than a neutral amping. Listening to Vivaldis Four Seasons, however, the highs of the violins come in strong, brilliant and exciting, letting you really feel the music.

I believe what the PM-3 represent is the superiority of planar drivers, with the ability to play without distortion, and to quickly produce sounds, where dynamics (unless multi driver with crossover) would fail.

My one true complaint about the PM-3 (soundstage and separation not being one, as I cannot fault a closed back for not sounding open) is the cable length. It isn't so much that the stock cable can't be useful, but a second shorter, on-the-go length would be nice, allowing one to slip their player in their pocket and not trip over the cord while walking. After a short bit of research, I found the Moon Audio Blue Dragon, but I am undecided as to whether it benefits the sound enough...paying the price to get a better length is not worth it on its own.

Overall, near perfection, open back is about all that would improve the sound, but that would sacrifice privacy and isolation.