Headphone Reviews

Sound Quality
With two pairs of quite similar headphones and four pairs of likewise similar sounding ear pads, listening test for these cans was arduous and somewhat frustrating. Hair splitting isn't particularly fun or easy, especially when faced with the mailability of subjective impressions. I wish I had two pairs of each pad so I could switch more quickly between the PM-1 and PM-2 with the same pads on each. None-the-less, I did find some lasting impressions.

When the PM-1 first appeared it came with two pads: leather and velour. Personally, I preferred the velour pad as it seemed to reduce some low treble glare and seemed to have a more damped sound. With less glare, I heard better bass and treble detail, though I admit it may be a bit too polite sounding for most folks.

When the PM-1 Alt pad came along, it certainly did brighten up the headphones a bit and give them a more neutral sound, but I also heard the treble as being slightly more artificial and sizzly sounding than the leather pad.

Enter the PM-2, now with a little less damping behind the driver and synthetic leather pads with a design similar to the PM-1 Alt pads. For me these cans added a bit more treble sizzle to the mix, along with a bit more sub-bass response. I also heard the PM-2 as a bit more confused sounding—getting a bit more muddled-up—on complex passages than the PM-1.

What I think I'm hearing is that both PM series cans have a bit of an artificial sounding treble. I wouldn't characterize it as harsh, but rather as somewhat artificial. A pure "s" sound takes on a hazy zing sounding a bit more "zth" than ought be. While changing pads around, I found myself oscillating between "too much zing" and "too much damping" without really ever finding a happy medium. It's this character that keeps the PM-1 and PM-2 from being reference level headphones.

I need to remind the reader at this point that while I have put words to my listening impressions and in so doing have drawn out distinctions, those distinctions are in fact substantially smaller than the words might indicate. Regardless, preferences did arrise for me.

My personal preference for a damped, punchy, and somewhat rolled-off sound had me gravitating to the velour pads, but by the end of my comparisons this time around I found myself feeling the were a bit too muffled sounding with both headphones. The velour pads definitely take the edge of any low-treble hardness (not that there's much to start with), but in the end they were just a bit too colored to recommend broadly.

Likewise, the leather pads on the PM-1 seemed a little too damped. In the end I found myself preferring the PM-1 Alt pads on the PM-1 as the best compromise of the various factors.

The PM-2 seems a little brighter than the PM-1 overall to me. As a result I found the PM-2 stock pad and the PM-1 Alt pad slightly brighter than when used with the PM-1, and ended up preferring the PM-1 leather pad on the PM-2.

Comparisons to Other Headphones
Comparing the PM-2 with PM-1 leather pads to the latest Audeze LCD-2 Fazor I found them fairly similar. The LCD-2 had a bit better bass extension and had a bit more treble clarity—though I still find them a bit grainy and unrefined relative to the LCD-3. On the other hand I felt the mid to treble transition a bit more lively on the PM-2. It's a close call, which is a good showing for the $300 less expensive PM-2.

Switching to the venerable Sennheiser HD600 ($399) for comparison, I found quite a bit of similarity here as well. While I found the HD600 mid- and upper-treble a bit hazy and indistinct, it did seem a little less artificial than the PM-2. The lower treble of the HD 600 was a bit more forward and harder sounding than the PM-2; here I think the PM-2 was the better listen being a bit more balanced. The PM-2 bass pretty easily bested the somewhat looser sounding HD 600 to my ears.

I know people will want me to compare these to the HiFiMAN HE-400 and HE-560. I find both these cans too bright by quite a lot for my taste. While I though the HE-560 was possibly my favorite HiFiMAN headphone to date, they are still too far from my tastes to give them a fair review. So, sorry, no significant comparison from me.

Summary
I think Oppo may have gone a bit too far in brightening the PM-2 after the PM-1 introduction and resulting customer impressions of it being too rolled-off. Not to worry though, as purchasing the PM-1 leather pads for the PM-2 puts it right in line with the current PM-1 with Alternate pads. (Don't forget to consider buying the longer mobile cable while you're there.)

The PM-2 ticks all the boxes for a luxury general purpose/portable headphone. Though open, they do provide a little more isolation of higher frequencies than most open cans. Build quality is top-notch, and styling is masculine and understated. Comfort is very good even though the headphones are slightly heavy. And the PM-2 is efficient enough to be easily driven by portable devices, though it will sound better as the quality of gear driving them improves.

For me, the PM-2 is so similar to the PM-1 that I have a very difficult time separating the two. The stock synthetic leather PM-2 pad is too sizzly for me, and were it not for the opportunity to swap it for the PM-1 original leather pad I probably wouldn't put it up on the Wall of Fame. But with the PM-1 leather pad I find it pretty much the equal of the PM-1 with Alternate pads. As such, I see these two cans as part of a system of headphones and pads that lets you mix and match for your personal preferences and price point. So, I'm going to put them up on the Wall of Fame in the same paragraph as the PM-1 with links to the two reviews and pad article and let people looking for a luxury portable sort it out for themselves.

Video

Resources
Oppo Digital home page and PM-1 and PM-2 product pages.
Oppo's page describing the differences between the PM-1 and PM-2.
InnerFidelity review of the PM-1 and article on Oppo pads.
Head-Fi threads for PM-2 and PM-1.
Really good Head-Fi PM-2 review here.