The Oppo PM-3 A Competent Comfortable Mobile Headphone Measurements

Measurements
Click on graphs image to download .pdf for closer inspection.

It's worth mentioning at this point that I have now measured three PM-3s. The first one seemed to have erratic behavior at around 6-9kHz. I received a second pair for measurement some months after the first pair; this second pair did measure differently and did not exhibit the behavior. I then grew concerned because I didn't know if I was seeing an early sample that wasn't quite up to snuff or poor manufacturing tolerances, so I requested a third pair be overnighted to me. The third pair did quite closely match the performance of the second pair. My feeling is that I just receive an early pair the first time and manufacture had not been quite dialed in. All charts are available to view: Sample A; Sample B; and Sample C.

I've gone over the frequency response pretty comprehensively in the review itself, but to recap: The raw response shows a headphone not too sensitive to position on the head. Frequency response is very close to the Harman target response, deviating only in the bass rise extending slightly too far into the mid-range; the dip between 4-8kHz; the top octave is slightly too rolled off; and the peak at 3.2kHz might be a few dB too high. Regardless, I'd say this is the closest headphone I've seen to the target curve. See page two of this review for a Harman curve corrected frequency response.

30Hz square wave is a little misshapen by the pad bounce that can be seen in the frequency response curve between 80-200Hz. I've personally never been able to hear any problems due to the propensity of pads to resonate on the springiness of the foam...well, maybe the DT48 which has it to the extreme. Otherwise, the 30Hz wave shape is good staying above zero for its entire duration and with no sway back. Always good to glance over and look for bass distortion at this point, and notice very little evident with the PM-3. The PM-3 has good bass response at a level that doesn't draw attention to itself.

300Hz square wave shows a pretty significant overshoot of the initial edge; I attribute this to the slightly excessive FR peak at 3.2kHz. I would have expected this headphone to have an edgier quality looking at that spike, but I guess the frequency component of the feature is in just the right place for it to sound good even though it's a bit emphatic. There is a small second ring after the initial spike, but very little noise thereafter. Likewise, the impulse response looks a little slow to me, and there is some subsequent stuff, but it's generally pretty clean relative to most headphones. FWIW, I didn't hear any graininess in these cans.

Distortion is very low in the PM-3, and the 100dB curve lies at or below the 90dB curve indicating these cans can play loud well, which I did hear in listening. Impedance and phase are nearly flat, a characteristic common to planar magnetic headphones. Impedance is at 26 Ohms.

Isolation plot shows quite good isolation, these will cut down background noise well and others will have a difficult time hearing your music as leakage is quite low.

At 47mVrms to achieve 90dBspl, the Oppo PM-3 will play at satisfying levels with portable devices.

COMPANY INFO
Oppo Digital
2629 Terminal Blvd., Ste B
Mountain View, CA 94043
(650) 961-1118
ARTICLE CONTENTS

COMMENTS
Claritas's picture

The pads are listed as 60 mm, but they're actually 57 mm! Whereas the average guy's ear in America is 65.9 mm. Their being average size for the industry doesn't change that. The bottom line: this isn't going to be circumaural for *most* people. It's a failure of design, plain and simple.

zobel's picture

These are dead in the water for me for that reason.

Tyll Hertsens's picture
Thanks for your comment. Your numbers look legit. I'm going to have to think about this for a while to know where I come down on it. These cans felt cozy, but not confining to me at all. I don't know that I'd call it a failure of design, there may be mitigating factors---maybe when the pads get bigger they also get less stable on the head, the ears may register the headphone better in place and actually feel more comfortable. Dunno, just saying that I wouldn't be too quick to judge. My ears are 66mm, so about average. The FSP and original Momentum were problematic, though. Anyway, thanks for the poke, I'll keep it in mind.
zobel's picture

They wouldn't work for me. What size ears do they fit?

Tyll Hertsens's picture
Mine are 66mm and they seem fine. So mine are boggier than the opening, yet it doesn't feel that way. Like I say, I'm gonna have to think about this a bit and ask some people some questions. Don't have any good answers right now.
zobel's picture

What size ears will these fit around?

JE's picture

Indeed it is a failure of design. Manufacturers need to understand that these pseudocircumaural designs are not doing any good. If you need portable, go for portable offerings. Circumaural headphones should guarantee big enough pads/cups for the best comfort AND sound quality.

I have discussed this numerous times in recent months on our website (headaudio.weebly.com) or discussion boards because I am really sensitive to pad sizing... It is a much more important topic than people seem to realise. In order to achieve a proper seal and comfort, you not only need large enough diameter but also enough DEPTH. The smaller the pads, the more your pinna or the surrounding area is 'interfering' and ruining the proper seal. Manufacturers then sometimes try to compensate for this using increased clamping force which is something I distaste as well. I sometimes wonder if they are trying to invent a new category of headphones: half on-ear, half over-ear.

I would be somewhat more willingful to accept a bit smaller earpads with dynamic offerings where the sweetspot radius is not ideal (due to the driver's nature => you have to take care about how to position the headphones properly on your head to get the ideal FR) but we are talking orthodynamic here. Look at the Hifiman headphones - extremely consistent despite different positioning. Why? Because they designed the section between driver and your ears properly. No need for smallish earpads with properly designed orthodynamic headphones.

halcyon's picture

Oppo would have easily gotten couple times more sales, had they made the pads user changeable and/or included even slightly bigger/deeper pads to begin with.

Yes, headphone design if full of compromises and so are sales!

TMRaven's picture

When beta testing the headphones, I found that the initial PM3 had very good if not the best vocal performance I've ever seen in a headphone, vocals just seemed so realistic and well imaged. The second version was a tad too forward in the upper midrange, causing it to lose some of that magic, so we settled on something that was a mix of the two. The end result was a headphone that still held the vocal magic of the very first beta PM3, but with some extra liveliness in the upper midrange and treble to 'lift' it off the ground.

The vocal performance just seems to be an inherent strength to the PM3 and its driver/enclosure, even if you tweak its sound somewhat. The ear openings are too small for me to be considered fully circumaural, but the pads are good enough for decent comfort for 30-345 minutes. I'm glad that Oppo and us Beta testers could work together to get a very good end result.

TMRaven's picture

I also prefer the PM3 to the PM1 as well.

money4me247's picture

I've posted a head-fi review on the PM-3 and I agree with the majority of impressions made here. I've always found Tyll's reviews to be pretty spot on if you take into account his personal sound signature preferences. I greatly enjoy the PM-3 and highly recommend people to try them. I also prefer the PM-3 over the PM-1 like TMRaven and Tyll.

I also personally found the PM-3 to also be very representative of neutral to my ears. I thought there was a subtle emphasis on sub-bass over other neutral-oriented dynamic headphones and some slight smoothing of the upper treble. I agree the vocals are a strong suit for the PM-3s with a very organic presentation of the midrange.

re: on the earpads, I've found the PM-3 earpads to actually be more comfortable than the PM-1/PM-2 earpads whose hard surface of drivers lightly brush against my ears. the foam disk that the PM-3 has above their driver really helps. I am one who has a lot of issues with earpad size, but the PM-3 was surprisingly comfortable for me without any issues.

ps: my review is found here for those interested (http://www.head-fi.org/products/oppo-pm-3/reviews/12713)

jcheadphone's picture

I had a chance to listen to the PM-3s at Axpona 2015 and I really liked them for their $399 price point. Of the new headphones I tried at Axpona I liked the PM-3s and Dan Clark's (aka Mr. Speakers) Either the best. Didn't get enough time with the HE1000 to form an strong opinion. I thought the PM-3a offered a better price to performance ratio that the new EL-8 and I own the XCs so I generally like Audeze products.

kman1211's picture

This headphone has been on my must listen list for some time. I can't wait to get a chance to hear it. I am curious how it stacks up against the DT 150 in terms of fidelity and scalability. Having similar levels of sound quality and what seems better neutrality in a more appealing and more portable package will be nice.

Hjelmevold's picture

Judging by the measurements, it should be really interesting to have someone compare the Oppo PM3 to the Soundmagic HP100/150.

The PM3 seems to be more practical due to its size and foldability, it has less harmonic distortion, cleaner impulse response, and more even bass response. On the other hand, the HP100/150 is cheaper (but with some issues with headphone cups breaking off), and has better isolation than the PM3. The frequency responses look fairly similar to me, with the HP100/150 being perhaps a bit more energetic around 10k.

Nomad_Soul's picture

Thanks for the great review, Tyll. How would you compare the comfort of the PM-3 vs the Shure SRH1540?

Tyll Hertsens's picture
The Shure SRH1540 is an amazingly comfortable headphone. More comfortable than the PM-3 and just about everything else in the category.
Long time listener's picture

"This 4-8kHz region can be really horrible sounding if over-accentuated—think piercing sibilance that makes you wince."

That's because THAT is the presence region--actually, it's defined by John Atkinson of Stereophile as roughly 2kHz to 5kHz, but close enough--and it's known as the presence region because that's where our ears can be most sensitive. Hence the piercing sounds if over-accentuated.

The following, I believe, refers to the midrange--and while the midrange has plenty of presence, it's not what is meant by "the presence region":

"I wouldn't characterize this as a big problem in the PM-3 because it means they're not strident—even though their presence region (say 800-3kHz) is a bit forward."

Cheers

Tyll Hertsens's picture
Not sure where you got that idea. From this Stereophile page:

"presence range The lower-treble part of the audio spectrum, approximately 1-3kHz, which contributes to presence in reproduced sound."

Seth195208's picture

..the experts always say "Don't be swayed by the exciting sounding ones, because what sounds exciting for five minutes in the show room sounds irritating and fatiguing for more than five minutes at home" The same thing goes for headphones. The difference between "long term exciting" and "short term exciting" is a very fine line. After listening to these headphones for a couple months now, I can say with confidence that Oppo nailed it!

Tyll Hertsens's picture
Wish I had a "like" button for posts. Yours would get one, you're exactly correct, IMO.
MLegend's picture

So wait.....since there are 3 different frequency response graphs which one represents the final version of the PM-3 available to consumers today?

Tyll Hertsens's picture
Sample B and C. The first one was early production. Samples B and C are quite close.
emelius's picture

Any comments on where the wired version of the Sennheiser Momentum 2.0 Over Ear might fit into the mix?...Forthcoming?...

Tyll Hertsens's picture
Requested numerous times, they just aren't available yet for reviewers. (I think they're pushing the wireless versions ATM.
potterpastor's picture

I'll send you my Sennheiser Momentum 2.0 for two months if you let me use your HD 700 for two months.

Tyll Hertsens's picture
I don't have an HD 700 here.
subguy812's picture

Sennheiser created confusion by releasing a wireless and a wired version so close to each other. Many folks think if they listen to the M2 wireless in passive mode it is the same headphone as teh wired only version...two different worlds. M2 wired is a much better sound signature.

ADU's picture

But what's up with the treble on this puppy?

http://cdn.innerfidelity.com/images/Oppo_PM3_Graph_PM3HarmanCompensation...

It looks like there's a modest rise in volume between 10Hz and 4kHz. But the average dBs appear to take a nose-dive above 4kHz.

I'm looking at the two compensated curves on the top of graph btw.

ELPCU's picture

And you are right about above 4khz IMO.

I won't say there is modest volume rise from 10hz to 4Khz, because frequency below 20hz is virtually not audible. You should look after 20hz, and these slight volume difference from 20~40hz is very very hard to distinguish. And I can still say the bass of this PM-3 is extended extremely well. Yes, extremely.

Considering these information, you will say it is about flat from 30hz to 2khz. and very slight emphasis from 2khz to 4khz.

And from 4khz, it drops. I consider -5dB line on graph is about reference line of this graph. And it drops like 7~8dB.

There is definitely noticeable treble drop in this can. I notice this right away when I started to compare my Sennheiser HD 600 / hidition NT-6. Though it is not terrbie by any mean. Good thing is that around 6khz is frequency range that makes treble harsh. It is range of sibilant sound. having a drop on this region make this PM-3 more relaxing, and much more comfortable sound.

At the same time, you can clearly argue this is a bad thing, and I believe it is the bad part of this can. Probably the biggest complain of mine.

Though I just cannot complain too much, because 7~8dB trench through small region is not a worst thing, and having trench right on sibliant region has some pros; And PM-3 offers everything including overall design, quality & finish, isolation, comfort, uniqueness(hey, the only outdoor planar magnetic), price, and sound quality except that treble portion.

I just cannot complain too much. Overall, I agree with Tyll. Your point is right. It is definitely worth of mention, and it is arguably cons, but it is not too bad.

All I can say is if your are treble geek or treble enthusiast, then you have to think twice before purchasing this can.

ADU's picture

It helps to get some confirmation from another user on this question.

There are some fairly prominent spikes in the 9-10kHz treble range on the Oppo PM-1 and PM-2...

http://www.innerfidelity.com/images/OppoPM1.pdf
http://www.innerfidelity.com/images/OppoPM22014StockPads.pdf

...so maybe that's one reason the treble was dialed back a bit more on this newer PM-3 model? If that's the case, perhaps they overcompensated a little too much.

I was also wondering though if some of Tyll's tweaks to the Harman curve could be slightly exaggerating the falloff above 4kHz in the corrected curves on this PM-3 plot...

http://cdn.innerfidelity.com/images/Oppo_PM3_Graph_PM3HarmanCompensation...

Or does the downward tilt between 4kHz and 20kHz on the upper curves seem about right in people's experience with this headphone?

FWIW, the NAD VISO HP50 still looks a bit flatter to me on its Harman plot (though it has a slightly darker overall tilt than the PM-3, and isn't planar-magnetic)...

http://cdn.innerfidelity.com/images/140321_Blog_HarmanResponseFR_NADVISO...

Since these seem to be two of the top contenders in the "flatness wars", did you give the NAD any consideration before getting the Oppo PM-3?

Also, how different is the sound quality on the PM-3 vs. a regular headphone? And which do you like better?

Appreciate any further thoughts you or others may wish to share on this subject.

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