I quite like the Oppo PM-1 overall. I also have a lot of reservations about it. While I can see why many consider this a disappointing product, I think it has a lot going for it and, at the very least, shows enough signs that future iterations could be damn good.

Presentation, Looks, Comfort

You've all heard about the packaging and the box. It's a very, very nice touch. That all alone makes me want to believe this headphone is truly worth the price. Would I rather have simpler packaging and, hopefully, pay a bit less? The box is so pretty, but, yeah...I think I would.

The headphone itself looks and feels great. The design is simple, modern, and stylish. It looks expensive. The build quality is good. It feels expensive. I quite like the ear pads and how easy they are to replace, but the modder in me is disappointed that the design and implementation is rather unique and would be hard to work with for other pads (I think some deficiencies could be slightly improved with different pads). The cable seems nice, but I'm not sold on the connectors they use in the cups. They feel and look good for being small, but I could see them being a weak spot as well.

Comfort is pretty good. Again, the pads are nice. The headphone isn't too heavy overall, but it could use a bit more cushioning in the headband or perhaps a better shape/fit for weight distribution. The top of my head started to get sore within an hour, but it could be worse. I'm picky in this regard.

Sound

I'm probably in the minority here in that I actually really like how the PM-1 sounds. It's not perfect by any means, but it just so happens it's very agreeable with my ears. I find it to have a very natural and effortless presentation. I generally thought it had a good tone and overall frequency response balance. It has a bit of a warmth and bloom to it, and it is rolled-off at the extremities. That said, it still has decent, but not great, extension and an overall balanced, fairly neutral sound. It's one of the few headphones with a sound I didn't have to adjust to when I pressed play. I could just slip right in and enjoy the music.

But, as I said, not all is perfect with the sound. The center image is good and has decent depth, but the rest of the soundstage seems to wrap right around the side of your head. For some genres, this doesn't matter too much. Thankfully, this isn't an area that bothers me a whole lot. I know some are less tolerant with these sort of issues.

The sound could also use a bit more liveliness and dynamics to it. Part of this is simply due to the rolled nature of the sound signature at either end of the spectrum. They are certainly a laid-back, smooth headphone (something I like). Yet, part of it just sounds like the headphone is stifled and over-damped despite that. The sense of air is lacking, and it seems there is little room for reverb and decay. For a lot of what I listen to, I don't mind it, but sometimes it can get weird. Ignoring the warmth, while the headphone is fairly clean and fast as a whole, it also has a slight limp-dick or ethereal quality to it. They also aren't super resolving and are, if anything, a bit veiled (again, still fast and clean). I don't mind all this so much. In fact, I most often find these traits to be desirable when listening, as I am very quick and easy to develop hearing fatigue. It all comes down to personal tastes. But, still, a bit more oomph in all categories wouldn't hurt. However, sometimes all that matters is if I can melt into a headphone without thinking about it. The PM-1 does this better FOR ME than most other headphones. (I'm really wondering what I'd think of the HD600/650 and LCD-2.)

EQ seemed to help the headphone's resolving abilities quite a bit, and it did help extend the soundsta ge a touch more to the front and sides. It still wasn't great. I'm wondering how much you could change this with mods and, in particular, angled ear pads. EQ in the bass and treble can bring back some of the liveliness, but it still retains that somewhat soft quality before it just starts to sound weird, shrill, and off (EQ can only do so much...).

I know a lot of these downsides can just kill it for some people. Just look at the mixed reactions already available on this site. But, for whatever reason, I simply really like how these sound. They fit my tastes and do well where I need them to, and the downsides just simply don't matter as much to me as they might for others. Do I think they are worth $1K+? Even with the nice box, no. Ditch the box and I'd easily drop $300-400 on the PM-1, though not before demoing the HD600/650 and making sure they wouldn't better fit the bill. If a newer model releases in the future and addresses the downsides I mentioned, I could see myself paying $600-700. Maybe offer the nice packaging and box at an extra cost for those that want it (and I admit, I might...).

Measurements and Analysis (Velour Ear Pads)

Updated measurements using new compensation curve: http://www.changstar.com/index.php/topic,1590.msg44503.html#msg44503

I've attached the following measurement images:

1. Frequency Response
2. Left Channel FR and Harmonic Distortion (ignore dip in D2 from 1-3KHz, as it is an artifact...should be fairly linear line)
3. Right Channel FR and HD (ignore D2 dip again)
4. Left Channel CSD
5. Right Channel CSD
6. Left Channel Raw - two measurements of left channel from left and right ear each, averaged for above FR (before compensation)
7. Right Channel Raw - same process

My measurements indicate that, at least as I hear it, the Oppo PM-1 has a sort of upside down, U-shaped frequency response. Fairly smooth and linear overall, though the balance does explain a lot. I think my measurements overestimate how rolled they sound, subjectively. Channel matching is good. The harmonic distortion from 100-500Hz isn't great, though I don't find this to be too detrimental to the sound. It may further contribute to the warmth and bloom I heard. Other than that, the distortion is low. CSDs are fairly clean, and that matches what I heard. My raw measurements suggest the headphone is relatively insensitive to position and seal (subjectively confirmed), which is nice. It does appear my two ears produce slightly different results, which is why I take measurements of each channel on both ears and average them when I can (PM-1 works well for this, but some headphones simply do not). This seems to work well in the end.

Compare to Ultrabike's measurements at the beginning of this thread (same PM-1) and Tyll's measurements here: http://www.innerfidelity.com/images/OppoPM1VelourPads.pdf

It may be too technical for the masses...

Such a small thing could be easy to overlook though. 

It just trends towards a somewhat light and soft sound due to the rolled nature at either end, that and likely the damping material used. Rolled bass gives it a slight lack of presence, body, weight, impact, etc. The rolled treble is soft and inoffensive. Not the most proper use of "ethereal" based on its definition, but that's just what made sense in my head when listening. That and "limp-dick." The Alpha Dog, in comparison, actually had some balls and could get itself up at the expense of not sounding quite as smooth and natural. Even metal can be relaxing on the PM-1.

It's audio. The terms don't have to make proper sense.   Alternatively, look at my avatar and assume it's better to not try to understand me sometimes.