Reviews by gardibolt


100+ Head-Fier
Pros: Wide soundstage, exceptional sound on solo strings, fine clarity, performs well on problematic sources, great build quality
Cons: Ear cups a bit small
I spent a week with the OPPO PM-3 through the head-fi loaner program, and got the chance to try them out on a variety of pieces. 99% of my headphone listening is classical music of one type or another. My principal source is an iPod Classic, with a solid state drive upgrade to 256GB, with most mp3s at 256k. So I'm not starting with the highest quality sources. On the other hand, at my age I no longer have much of any hearing above 10kHz, and I like historical recordings, so the source often isn't the greatest in the first place. The main goal was to simulate my typical listening anyway, so this testing accomplished that. My other headphones are low-mid level, and these are the first set I've had access to that are more on the high end so I was interested to try them out. Since these have already passed through many hands, I've assumed they have all the breaking in that they need. Many thanks to Oppo for making these available.
My first impression on opening the box was that these things are built like a tank. They're incredibly solid compared to any other headphone I've had or used. Serious build quality that's quite impressive, and there's a clean and attractive design. The pads are a shade small for my big ears, but even though I have a very large head I had no difficulty getting a good fit. The nice thickness of the pads helped the comfort level substantially. I listened to two acts of Wagner's Die Walküre without discomfort or getting warm and sweaty, and that's close to three hours straight. 
The cables were one-directional, which took me by surprise. When I first plugged the cable into the phones, I only got sound out of the right channel. When I reversed the cable it fit much better and I got both channels. Oops.
I then used a variety of pieces to test the PM-3 against two of my other headphones: AKG K550 and Sony MDR-7506 (unmodified). These both came highly recommended from several sites and I've been happy with them most of the time with classical music. I also often use a Fiio E11K portable amp with them; the K550 generally doesn't need the oomph but the 7506 definitely does. This is my first time A-B-ing, let alone A-B-C-ing, multiple sets of headphones; I truly was not expecting to hear substantial differences between them but I quite clearly did. The OPPO unsurprisingly performed at least as well as the others, and often did substantially better.
Here's the breakdown of what I listened to for testing and what the results were:
1. J.S. Bach Cello Suite #1 , BWV 1007 Janos Starker (Mercury). For this comparison I didn't use the amp, but fed the headphones directly from the iPod Classic, just to see what would happen. The AKG had a mellow, throaty quality, and felt a bit blurry; there was a room-filling reverb to the point of almost being claustrophobic. The harmonics, especially at the end of the Courante are nice. It feels like a cello in your head. The Sony is lighter, with a thinner, airier texture. It felt less cramped but also more distant than the AKG, as if the cello is 2-3 feet in front of you. The harmonics are less pronounced as is Starker's breathing. The sound is pleasant but limited. 
The OPPO provides the best aspects of both, with a vibrant immediacy but absent any cramped feeling. It offered very nice subtleties in volume changes. It's a much smoother and subtler experience. The harmonics on the Courante are still excellent but a bit less in your face. One thing I learned from the testing sessions was that the OPPO handles solo strings such as violin and cello exceptionally well. After I finished testing I flipped through many solo string pieces from baroque to bluegrass, and it was one delight after another. The harmonics and the scratch of rosin on the strings comes across marvelously well on the OPPO, amplified or not.
2. Richard Strauss Also sprach Zarathustra op.30, Leonard Slatkin, Lyons Symphony Orchestra. This is a live recording that has a number of problems associated with it (poorly miked, noisy audience, etc.), so I was interested in seeing how well the various headphones handled them. For this and all the remaining tests I had the amp on and kept it at a constant setting. The AKG shone on the deep bass of this piece, with the famous organ pedal in the introduction in particular coming through loud and clear, but occasionally getting a little rumbly. The timpani comes across very hot and the rolls are smeary. The audience coughs a lot, but the AKG kept that fairly well in the background. The Sony MDR-7506 was weak; it just can't handle that low C pedal at all, and overall it's lacking in presence. The all-important timpani sounds distant. Overall, the performance comes across crisply and with pretty good clarity, but it's at the expense of all the drama.
The OPPO had no problem with the big organ pedal, which is nice and solid, but the sound doesn't rumble as it did on the AKG. What struck me most was that unlike the other two the OPPO had a HUGE soundstage. There was a definite feeling of a very large orchestra spread out in front of you. Again, the crescendos come across much better on the OPPO, as do the pizzicati. The coughing was amusingly pinpointed; while the others just offered up an annoying cough somewhere, with the OPPO I was amused to note that I could tell *exactly* where the offenders were sitting (I'm not sure that's a good thing, but it help points up the accuracy of these headphones). The woodwinds, particularly the oboe, come across best. This recording has issues with the brass being smeary and poorly miked, and unsurprisingly none of the headphones were able to do much about that. The violin solo and the clang of the tubular bells are worthy of particular mention; they are vivid and quite wonderful through the OPPO. Even though the source material is dodgy to be charitable, it sounded best from the OPPO, so high marks for dealing well with a problematic recording.
3. Ludwig van Beethoven Symphony No. 7 in A, op.92; Claudio Abbado, Berlin Philharmonic (DGG). I am a Beethoven aficionado (I am Project Director of The Unheard Beethoven website) and I listen to a lot of his work, so I wanted to try out a couple of Ludwig's pieces on these headphones. I selected the third movement Presto from the 7th symphony; Abbado takes this at a frantic rate, with the high potential for loss of clarity, but it's an excellent recording. The AKG acquitted itself quite well, even though it presented a fairly narrow soundstage. I particularly liked its treatment of the menacing bass line in the horns, which came through clearest on these phones. There is a sense of added reverb. The flutes and oboes are on an even par. I didn't however, get a very big contrast between the pianissimo and the forte parts of the movement. The Sony had more emphasis on the lows and also brought forth a sweet and clear sound, with generally well-defined instruments. The flutes felt subdued compared to the oboes, and the timpani sometimes felt a bit blurry. But given the very high quality source, there really wasn't a huge difference between the three headphones.
On the OPPO, the strings are very well-defined and the woodwinds are exceptionally clear and immediate; the timps are crisp and unblurred. Where the OPPO really came to life was on the crescendi; for some reason the volume variance was much more substantial on them--which may account for the horn bassline feeling a bit distant or recessed. By comparison the dynamic ranges on the other two feel highly compressed, and that's an issue for Beethoven, who delights in dynamic contrasts. Both the AKG and the OPPO did very well on this piece in different ways. 
4. Ludwig van Beethoven, Piano Sonata #32 in C minor, op.111, 2nd movement (Arietta). Sviatoslav Richter (Decca). This was an interesting piece to try since Richter plays the first section very slowly and calmy, so it gave an opportunity to hear how well the various headphones handle overlapping slow decay from the piano. The most striking difference between the three headphones was that it felt like Richter was playing in an entirely different room on each. The AKG felt the biggest, probably 30x50x20, a huge open room with a fairly high ceiling. The recording flaws were noticeable, and Richter's pedal releases were very obvious. The boogie-woogie variation is nice and crisp, with good volume changes (in fact, all three handled the volume changes quite well indeed). The Sony felt more forward, cleaner and crisper almost to the point of being antiseptic. It felt like a quite small room, perhaps 10x20x8. The recording flaws (particularly the hiss) are least noticeable on the Sonys, and it felt more lifelike than either of the other two, albeit in a somewhat cramped space. I can't say I liked the sound, though.
The OPPO had a soundstage that fell right between the two, and felt like a room about 20x30x12; while it had a broad and realistic soundstage, it was still quite focused. Richter's pedaling was not nearly as noticeable as on the AKG. All three handled the decay of the piano and the harmonics just fine so I was pleased on that count. But it was a very different experience listening to the piece on the three headphones. None of them were bad, and each had some merits. I'm calling this one a draw, with perhaps a slight edge to the OPPO.
5. Giuseppe Verdi, Rigoletto. Maria Callas, Tullio Serafin, La Scala Orchestra (Pristine Classical), Gilda's lovesick aria "Gualtier Maldè" from Act I. I am also a Callas fan, and while her voice isn't exactly beautiful, it's nevertheless an amazingly expressive instrument. This recording is a reworking of the 1955 EMI recording by Pristine, cleaning up some noise and pitch variation problems, and adding their "Ambient Stereo" processing to the mono recording. That's a fairly subtle treatment that opens up the recording some without the extravagant "electronically rechanneled for stereo" treatment that usually gives nightmarish results. Hiss was prominent on the AKGs. The flutes in the orchestra are a bit too forward. Callas' "little girl" voice here comes across very well.  Callas' enunciation is reasonably forthright, but her high notes are a bit piercing. The upper register just feels a bit hot, although Callas' portamento glides lusciously. The Sony again had a much thinner sound, with Callas' voice being much more forward. Sony apparently is having none of the "Ambient Stereo" business; it feels like mono in these headphones, with just a slight fringe of stereo on the edges. Again, the flutes are hurting and there's a bit of a warbly sound to them. On the other hand, Callas is clear as a bell and the voice seems cleaner and her words are much easier to understand than on the AKGs. Her high notes have no unpleasantness.
The OPPO again provides a very broad soundstage; Ambient Stereo is A-OK with the OPPO. The hiss is still there if you listen hard but it's not very pronounced. This time, the flutes are almost too forward. Callas' voice is again very clear and with an excellent immediacy. Her trademark sound is almost emotionally overwhelming here. The high notes are big but controlled, without piercing. Again, the OPPO does well with crescendos, which are much more noticeable. The series of descending intervals in Callas' voice is breathtaking. While the Sony did well on this aria, the OPPO just destroyed it in bringing out the extraordinary colors of her voice so well. After the test I went back and sampled a number of other Callas opera and aria recitals. I got that same feeling from the studio recordings of her voice that are well done. Her live performances don't have enough sound information to be able to get that feeling across, but the Callas studio performances are really a delight listening to with the OPPO.  I wish I had time to listen to several complete Callas operas with these. If you're a Callas fan, these headphones are a real treat.
6. George Gershwin, Piano Concerto in F, third movement Allegro agitato. Eugene List, Howard Hanson, Eastman Rochester Orchestra (Mercury). The Mercury Living Presence recordings are all excellent, and this is a particularly vibrant and fun performance. The repeated hammering of the piano on a single note or chords offered a special challenge to the headphones. All three headphones offered a very wide soundstage. In the AKG, the orchestra is almost too big, and the piano has an equally big sound. It's almost overpowering. The rat-a-tats in the piano are a shade unclear, and the glockenspiel is lost in the orchestra. The muted trumpets do come through nicely. This recording has a ton of edits, and they're almost obtrusive in the AKG. The thumping bass is aggressive and the strings are a shade whiny, but the stereo effects come across exceedingly well. The violins' main theme comes across as syrupy. This was a bit of a disappointing listening experience. The Sony is again more subdued as far as the orchestra goes, and the piano is brought far foward. The piano sounds less brittle than on the AKG. The edits with the Sony feel less prominent, while they're still clearly present. Where the Sony really excelled was differentiating the varying pressure as List hits the keys; nothing mechanical here. The violins' theme comes through much less syrupy and a shade subdued.
The OPPO not only brings the piano forward, but also the percussion. It's lively, but not out of balance. The winds also feel more discernable. The edits are the least annoying on the OPPOs. I heard a quiet glissando on the piano that was buried completely on both of the other headphones. The violin theme is smooth but not saccharine. The forward percussion also allows the OPPOs to impress with the decay of the gong at the climax. While the OPPO again comes out ahead, this time the Sony isn't far behind.

So in summary the OPPO did at least as well as the other two headphones I tested against it, and in some cases, particularly for solo strings and for voice, it just crushed the other two. I was surprised at the wide variance between them on the same source material, which was far beyond what I was expecting. The difference in the soundstages, especially on the Richter, was particularly shocking. The OPPO came out best in that aspect every time. The OPPO does very well with classical music generally. If you listen to solo strings or chamber music, the OPPO truly shines there. The OPPOs acquit themselves with credit when dealing with problematic source recordings as well. I'm very pleased with the opportunity to have tried them out and I suspect I'll be searching for sales on them in the not too distant future.
UPDATE Nov.2016: I bought a refurb set of the PM-3s from OPPO a few months after writing this review, and I love them. Whenever I am doing serious critical listening, I turn to them. I'm still astounded by the clarity of the soundstage on recordings I thought I knew well. [Some small edits for typos in the above review]
Hi gardibolt, Thank you for the review.  I also use the PM-3 and I also listen primarily to classical music.  I agree with you that it's a very good pair of headphones.  Period.  When one considers the price, it's easily one of the best recommendations. 
@gardibolt - I too primarily listen to classical music, and I certainly appreciate your review. Thanks!
@gardibolt Great Classical-focused review! I enjoy my PM-3s on the road or when I'm in an environment where closed HPs are the better choice (e.g. airplane, coffee shop, cube farm) where isolation is key. I prefer the similarly priced HiFiMan 400i if I don't want or need closed HPs.