Oppo PM-3 Review and Measurements

OPPO PM-3 Review and Measurements​

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OPPO has taken an interesting approach to their product lineup and launch timeline compared to what I feel like I’m seeing from most other manufacturers. OPPO started with the pricey PM-1, which I thought sounded pretty good, if not overpriced and a bit sleepy sounding. They then moved to the PM-2, which was essentially just a PM-1 with cheaper build materials and without the pretty wooden box. It was an interesting choice to start from the top and work their way down, not to mention how infrequently you see this copy-but-made-cheaper sort of product launch. But, anyway, the PM-2’s new pads and slightly refined internal damping, which Tyll at Innerfidelity brought to light, helped bring out a more neutral sound at the expense of some smoothness and refinement that I really enjoyed from the PM-1. I thought both models, while handsome and pleasing in many ways, just weren’t quite where they needed to be for the price.

OPPO continued their downward pricing trend with the launch of the PM-3. The PM-3 is meant to occupy a different headphone category than its older siblings. It’s still a planar-magnetic headphone, but smaller and more portable, easier to drive, and, oh, it’s closed instead of open. At $400, it gets close to being half the price of the PM-2. With the closed isolation and frequency tuning, it’s meant for a more on-the-go sort of situation, like in an urban or otherwise noisy environment, while still retaining some level of general balance. When you consider what OPPO was aiming for, I think they did a great job meeting their goals and then some. Sure, I have a few minor quibbles, but for all you get at the price point, there’s not a whole lot to complain about.

Comfort, Looks, Build Quality, and General Presentation

It’s no surprise that the PM-3 is a nice looking headphone with good build quality. Like the PM-1 and 2, it has a sleek, simple, and modern look. It shares a lot of their physical traits and design elements, actually. Lots of black and grey with a healthy mix of plastic and metal, though now you have the option of a white PM-3. Both color options look great in person. The brushed metal back is a nice touch. The PM-3’s edges aren’t quite as rounded as you get on the PM-1 or 2, but it’s almost not worth mentioning.

I do not like that the pads are not removable on the PM-3. I have to imagine there are ways to keep the same level of pad seal while allowing easily removable pads, but, hey, I didn’t engineer these. I just hate pads I can’t remove myself and always will. CORRECTION: Pads are technically removable, as someone pointed out to me. Just not the easiest things to take off. They are not adhered, but rather clipped on in a way that makes it seem so. Doesn't look as easy to get off as you'd normally expect from a removable pad, though, but possible.

Comfort is not bad on the PM-3. The PM-1 and 2 are more comfortable due to larger and deeper ear pads. If your ears are on the larger side of things or stick out, you may have difficulties getting the PM-3 to fit around your ears perfectly or have issues with your ears touching the inner lining of the pads. I think most will be fine here, but it’s something to keep in mind. Personally, it’s the clamping force that gets me. It’s a bit strong out of the box on the PM-3. You can bend the headband to adjust for this, but do make note that this may impede the PM-3’s ability to get a good seal and produce the strongest bass it can. If you have issues with its clamp, play around with bending the headband until you get it right. It’s a sturdy headphone, though do treat it with care nonetheless.

Like the PM-2, the PM-3 comes in a classy looking box, but not a wooden one, and includes a nice denim case. Coupled with its sleek looks and strong build quality, the PM-3 fits right in with the rest of the OPPO lineup. It feels like a premium product. When you consider the price, I think you get more than what you’d normally expect in these areas. But what about the soun d?

Sound Quality

Remember that the PM-3 was designed to work well for loud environments. It has inherently decent isolation and a tuned frequency response to work best for its intended purpose. When I first put the PM-3 on, I thought it had powerful bass and was a little bit bright. It doesn’t exactly have a U-shaped sound signature, but it’s not entirely neutral either. The slight brightness is certainly outweighed by the low end response.

The PM-1 and 2 always had some extra warmth to their sound, but they were generally flat or slightly thick at best when it came to low bass. With their rolled-off top end, both sounded a bit mid-centric and, at times, a bit sleepy. The PM-3 is not that. Compared to the PM-1 or 2, it kicks the bass up a couple notches and has a less warm tonality. Once you get into the low-mids and upper-bass of the PM-3, the response just gets stronger and stronger the lower you go. It has a lot of kick and impact. Generally, the bass on the PM-3 sounds strong and powerful, though at times it can get a little thick sounding. Think perhaps a bit too full-bodied rather than too muddy. But for a headphone being so bass-heavy, I actually think it’s more clean than not. It trends a fine line, really.

However, I have heard some say they do not hear the PM-3 as particularly bass heavy. I think there are a few possibilities that can explain this. First and foremost, the PM-3 is very sensitive to getting a proper seal if you want the full bass output. Even thin glasses have a measurable effect on the bass output. I don’t think it’s too difficult to assume, then, that even certain styles and lengths of hair or particular face shapes and features might prevent one from getting a perfect seal on the PM-3. Or it could even be different ear shapes and sizes affecting perceived response. Then you must consider how some judge bass differently. Some focus more on the upper-bass than the low-bass when quantifying it. Some also come from backgrounds with headphones with even more bass or, perhaps more commonly, headphones with higher distortion in the bass (which will often give the perception of more or stronger bass). Let’s also not forget the possibility of product variation, though I get the feeling OPPO is pretty consistent. You can see that trying to understand varying opinions can get tricky quickly.

The midrange as a whole on the PM-3 is relatively clean, clear, and neutral. With the strong bass and slightly emphasized treble, it might sound a little recessed to some. I don’t necessarily hear it that way, but there are a couple different ways you could look at the PM-3. I think it could be slightly better integrated with the bass and treble, to a lesser extent, but that’s just me nitpicking.

Treble on the PM-3 is interesting. Throughout the entire range, it never quite reaches the strength of the bass output, so any extra emphasis still doesn’t stick out too much. And emphasis or not, the treble is smooth and clean sounding. So, sure, it can be a touch brighter in spots than normal, but it rarely sounded harsh or too fatiguing even for someone with laid-back tastes like myself. The general treble emphasis on the PM-3 lies in that upper-mid to lower-treble transition area, not too unlike what I heard on the HD600. It’s not lit up quite like the K7XX, for those familiar with that headphone. If anything, the upper-treble on the PM-3 is a tiny bit rolled-off. I don’t hear anything as missing on the PM-3, but relative to some other headphones, it might lack that tiny last bit of sharpness, sparkle, and clarity you get from the upper-treble.

The PM-3 will never be the airiest or most expansive sounding headphone. It’s closed and on the intimate side of things. The soundstage is well integrated but a bit small. There’s not a ton of depth to the sound, but layering is thankfully not particularly blurred.

Sure, the PM-3 might not be quite as balanced tonally as the PM-1 or 2. It’s a bit cooler sounding and has a more “fun” sound signature. But, damn, it’s fun, engaging, and addicting to listen to! I can see this working really well in a louder environment, which I have not yet had an opportunity to really test it in yet.

In fact, the PM-3 actually has some improvements over the PM-1 and 2 to my ears regardless of having a more “fun” sound or not. For one, it seems to have more clarity across the frequency spectrum than its predecessors do. Transients seem faster and cleaner. Low-level details aren’t quite as masked. The PM-1 and 2 just have an inherently slower sound in comparison. No doubt, the PM-3’s frequency response plays into this perception, but I think it has some genuine improvements outside of that. For one, distortion seems better on the PM-3, but I’ll get into this in a bit. The PM-3 just seems to sound a bit cleaner and clearer in most ways than the PM-1 or 2. Snappier, if you will. Simple as that.

All in all, I think OPPO came close to nailing what they were aiming for. The PM-3 is not inherently meant to be the most neutral headphone ever, and that’s fine. It has a really engaging sound and seems to make some technical strides over the PM-1 and 2. Ideally, I think the treble response could be evened out a bit more so it’s not quite as bright sounding, and the mids could sound a bit thicker and better integrated, but I’m really nitpicking and don’t have much room to complain when you’re already getting so much at $400.

Let’s take a look at how they measure for me.

Measurements...Well, Notes First on Rig and Results, Then Measurements

First, I would like to mention a couple things about my measurement setup and methods:

- I use an in-ear mic for measurements, and my results only compensate for an inherent bass roll-off from my mic’s PSU. As such, these results are meant to at least somewhat match what I hear, given the coupler is my own head and ears. Since your ears and head likely aren’t physically identical to mine, you may hear things differently. My results are more meant to emphasize my point of view, not be some sort of averaged or absolute truth for all. Also note that flat on my setup generally means flat. No need to over complicate reading these.

- If possible, I take measurements of each channel from both ears. Given the PM-3 has a flat style ear pad, this is possible. I take four measurements of each channel from each ear, totaling to eight measurements per channel. These are then averaged.

- Harmonic distortion results are inherently limited in my setup and really only good for showing major problems. Results below 100Hz can be hit and miss as well and are the most limited or bottlenecked portion of my measurements.

- If you’ve seen any of my other measurements floating around on the internet, the PM-3 measurements are only comparable with other results from this year. Why? Because I got a new in-ear mic that I can fit deeper into my ear canal. This generally means I get more treble in measurements with my new mic. So, if you see anything from me that I measured last year, just make note that it’s not entirely comparable to results of anything I’ve measured from this year. There are more similarities than not, but for the sake of keeping things simple, try not to worry about comparing ’14 and ’15 measurements.

Now, with that said…

Frequency response results show a strong bass emphasis that is about 8 or 9dB up from the 1KHz point at 20Hz. It has a fairly linear decrease to the 300Hz point. I think the PM-3 could use a bit smoother transition from bass to mids, even if it meant you get more warmth in the midrange. It’s not that the bass sound disconnected, because it doesn’t, but the tuning does make the midrange sound a bit thinner than it could otherwise. The midrange is largely pretty good, though you can see that upper-mid through lower-treble emphasis I heard during listen ing tests. Personally, measurements are what they are, but I didn’t hear the PM-3 as rolled sounding at the top end as the graph makes it look like. Lacking air, yes, but not particularly rolled.



If you look at Tyll’s measurements for the PM-3, you can see how one might hear parts of the midrange as a bit depressed and disconnected relative to everything else. And depending on how you look at his results, especially the raw results, you might be able to see a bit of that upper-mid through lower-treble emphasis relative to some other headphones.

Here’s a quick look at how the response changes when I wear thin glasses. As you can see, even a small leak in the pads, and I do mean small, causes a noticeable drop in bass. Ignore that the response doesn’t look exactly like the graph above. This was just one quick measurement take for easy comparison’s sake, not a full set of averaged measurement takes.



Harmonic distortion results are pretty good as a whole. Keep in mind that the bass distortion creeps up because the response as a whole becomes more and more elevated as you go down the spectrum. It’s all relative. But, still, my setup is limited here and generally is the bottleneck for bass distortion results in low-distortion headphones. Tyll’s harmonic distortion results look pretty good and, interestingly enough, get very low at 100dB! Oh, and what’s this? No 300-500Hz distortion spike like the PM-1 and 2! Might play into the PM-3’s clean sound.





CSD results for the PM-3 are pretty good. Not the absolute best I’ve seen, but nothing to complain about. Naturally, the treble spots that are a bit emphasized aren’t going to decay as quickly as other spots.





Next up is the eight measurement takes that I averaged together to get the full frequency response measurement. Differences in various takes are largely due to in-ear mic insertion depth, though the headphones placement and fit does play a bit of a role too. Whereas Tyll moves the headphone to account for different placements, I have tactile feedback to let me know if a headphone is fitting right and like I’d normally wear it. Maybe you’ll find these raw results useful, and maybe not. But here they are.





Conclusion

I think the PM-3 does really well for its targeted, on-the-go sort of sound and price point of $400. I find them very fun and engaging to listen to, if not a touch brighter than I’d like at times. Think of them a treading that line between being somewhat neutral and natural sounding and the typical U-shaped, fun sound signature. It’s more the bass emphasis that makes them less than neutral than the slight treble emphasis, but, hey, the bass can actually be pretty fun. Measured results look pretty good for my setup. No terrible surprises or anything of the sort.

With the generally good sound quality, sleek looks, strong build quality, and overall premium presentation, I think the OPPO PM-3 is a great headphone and worth your consideration if you’re in the market for this sort of headphone. Sure, I’d like to tweak a few things before calling them perfect, but I highly recommend the PM-3.

 

Most likely unit-to-unit variance. Tyll measured 3 different pairs, I believe. All had slight differences. Being a beta tester myself, you could hear a mix of tuning and driver differences, especially when moving to a production unit. I doubt they changed anything post-production in terms of tuning.

Haven't heard Sine to compare. Would be interested (someone send me a pair, please? ).

I've heard all sorts of comments on the PM-3. Could be how well they fit or seal (or not) on your head. Even hair plays a role, and certainly glasses or the like. Some of it is general ear size, shape, and features that affect sound. Some of it is what other headphones we're used to relatively. Some of it is source and amp. Some of it is personal tastes. Some of it is hearing ability (could have hearing damage, be older than some and have natural hearing loss, etc.). Some of it is what you listen to. The list goes on and on and on and on. And then product variability as well, which is a problem with planars.

 

I think one of these (A?) was an early sample, but you can see some variation here:

http://www.innerfidelity.com/images/OppoPM3.pdf
http://www.innerfidelity.com/images/OppoPM3SampleB.pdf
http://www.innerfidelity.com/images/OppoPM3SampleC.pdf

 

They are less similar when you consider Tyll's dB scale. You're looking at spots with a good 2-3dB difference in a decent sized area of the spectrum.

You should ask @Audio Zenith about OPPO planar variance to see if he's noticed it or not. He has probably measured and modded more OPPO planars than anyone else.

FWIW, Tyll's HD800S measurements are much closer to each other. I can't speak for HD800 measurements, but pad differences might be at play from different pairs. I know my modded HD650 measured surprisingly similar to his stock HD650 (subtle differences because of the mod, not the headphone variance) when using the exact same pads.

 

See, this PM-3 was very bassy compared to the HD650. We're talking TH-X00 levels of bassy here.

 

I would take a modded Creative Aurvana Live over these after some recent experiences with the E-MU Walnut.