Oppo PM-1: A New Planar Magnetic Headphone!
Apr 16, 2014 at 5:08 AM Post #1,471 of 2,563
Now, for a few criticisms.  The LCD3 sit the drivers further back from your ears, so they have an easier time in some situations of moving the soundstage back and expand it a little over the Oppos, which come close despite their compact size.  The LCD3 are a bit more transparent, while PM1 are more forward and aggressive like my K812, producing snappy textures and deep pounding bass.  I think the two cans are equally realistic but  a bit different in presentation, LCD3 move things back a few rows while PM1 is more intimate.  PM1 are more in your face, but easily wrap the soundfield around your head in all directions.  
 
PM-1 should be a pretty straightforward choice for many.  They don't weigh much, they are very easily driven, they fold flat in a compact case which is something that few flagships can do, they fold up smaller than Edition 8's just about.  The accessories are more than generous.  Even the box that holds the wood box is like microsuede lined, made of heavy stock, it's pretty amazing how much work went into these.  Their price is lower than LCD2, but HE560 should be compared with these to figure out which is the best mid tier mid price ortho.  
 
Apr 16, 2014 at 5:09 AM Post #1,472 of 2,563
  The sound is on par with LCD3, with a bit more bass weight, in terms of wDhat echelon of sound quality we're talking about.  I'm not great at comparing stuff, I just know what I like, and I have enough bad headphones here (about 12 on my Wall of Suck) to know when a headphone deserves to be parked near my amp rack, and this is one, along with Alpha Dogs, LCD3, HD800, and K812.  I think everyone on this board would be honored to own a pair.  I'm having a great time here listening, and if you all actually read the about.com thing it's largely positive stuff except for 6db of distortion in a narrow part of the frequency band.  

Wow. I really do wish OPPO comes to Australia...
 
Does it sound like the DT 880 Pro at all?
 
Apr 16, 2014 at 5:09 AM Post #1,473 of 2,563
  Measurements at stereos.about.com are up now.
 
My expectation for these headphones was really, really high. And the measurement results ....
 
I just hope only the measured sample was defective!!!
 
Oppo must investigate what happened to the review sample measured there. The amount of ringing at 200-300 Hz is unacceptable by any standard for high-performance headphones (In fact, this is unacceptable even for $100 headphones). I measure speakers, so I know how audible this ringing (distortion) would be. This 5~6% THD IS audible. This is a typical amount of distortion I would expect from a low-quality 1 inch driver in a laptop around 300 Hz.

 
Wait, what speakers have you measured that have a cleaner decay around 200-300? How did you even reliably measure that low? It's certainly worth it to take CSD results in headphones below a kilohertz with a huge grain of salt. The 6% THD would likely be audible as a change in timbre for a critical listener provided they are familiar with the source recording (richer but fuzzier vocals, that sort of thing). It's not a deal breaker, but it is a problem.
 
+1 on marv's recommendation to switch from a linear to log graph at 90db and identify the 2nd/3rd harmonics to separate them from the more troubling higher order contributions.
 
  ... Talking about measurements without listening to the sound is almost a complete waste of time, especially to those people who want to read people's impressions and not a bunch of confusing technicalities ...

If you or anyone else is confused about the technical details, then isn't it worth it for participants to elucidate? I thought this thread was a general discussion of the PM-1, not merely an impression thread.
 
Apr 16, 2014 at 5:14 AM Post #1,474 of 2,563
These seem to have the bright midrange and neutral quality of Beyers, but they're a bassy ortho...but if I had to think of a dynamic that they're like, DT880 have plenty in common with these.  
 
Apr 16, 2014 at 6:00 AM Post #1,475 of 2,563
About those reverberations... Could this update explain a lot?
http://stereos.about.com/od/Measurements/ss/Oppo-Digital-PM-1-Headphone-Measurements_4.htm
 
Note that the original chart I posted showed a long decay across the entire audio band; on the original measurement I think I forgot to put damping material over the PM-1's open back, which I usually do with open-back headphones so that their sound doesn't reverberate in my lab.

 
Also, a wall-of-text has been added on the page with the harmonic distortion measurements:
http://stereos.about.com/od/Measurements/ss/Oppo-Digital-PM-1-Headphone-Measurements_5.htm
 
I've seen some commentary and speculation about this measurement on Internet forums, and I want to stress a few things that are necessary to understanding this measurement -- which, like most acoustical measurements, is easy to misinterpret...

 
Apr 16, 2014 at 6:34 AM Post #1,476 of 2,563
This thread is certainly going to oblivion in the not too distant future, again at this rate.
 
Quote:
  Wow. I really do wish OPPO comes to Australia...
 
Does it sound like the DT 880 Pro at all?

 
You can already order them here, on Opposhop.com.au
 
They are $1699
redface.gif
 
 
Apr 16, 2014 at 6:42 AM Post #1,477 of 2,563
  Guys, like I said before: Listen to some music with a pair and correlate that to any measurements. Talking about measurements without listening to the sound is almost a complete waste of time, especially to those people who want to read people's impressions and not a bunch of confusing technicalities. I'd strongly suggest that if you don't have either impressions or something useful to comment or ask about people's impressions then you hold back on posting and I'll open up Jude's original thread for all that discussion. 
smile.gif

 
I agree with you that some people dont want to read about measurements - but others do.  And yet others want to correlate measurements to subjective performance (I am in that camp).    So your idea of splitting the discussion makes sense - thank you for doing that.   
 
Now, re the point highlighted in bold above, with all due respect, I cannot disagree enough with it.  
 
Personally, I think more than half of the subjective opinions posted here are not worth the electrons used to display them, as we have no basis of separating fact from perception from placebo - i dont have a problem with that, but that cannot be the *only* allowed approach.    If people can post statements like being able to hear a different in soundstage (with IEMs, no less) across different firmware versions, then surely pointing out some specific issues with the measurements - a relatively more objective statement - has some value?   A lot of us CAN and are able to make atleast some inferences on the sound based on measurements - eg, looking at a headphone's treble curve sometimes (although not always) does give me an idea of whether i will like its sound or not.
 
I agree with you that measurements do not tell the entire story and there is no point to going only by numbers.    
 
However, there usually *IS* a relationship between measurements and the sound, and for a new headphone, i think a critical discussion of how the headphone measures is very valid.   After all, the purpose of Head-Fi is that people can discuss (not just praise) equipment and make informed choices.    For example, I can look at some measurements and know for a fact that the product isnt for me - that saves me paying for the product and the cost of customs/postage to have it sent to me.    
 
On a side note, it seems to me more and more that people tend to get VERY defensive the moment someone says anything critical of a product.   Take the original discussion - no one had a problem when there were pages and pages of posts going "oh, it is going to be fantastic" or similar stuff with absolutely NO basis in reality.   On the other hand, all it took was a couple of people to point out specific, fact-based issues (or potential issues) with the headphones and suddenly, the whole hive erupted.     What happens is that any critical comment or deviation from group-think gets shouted down/out and the people making those comments are made to feel responsible for derailing the thread - which, IMO, does a disservice to the head-fi community in the long run.
 
Apr 16, 2014 at 8:59 AM Post #1,478 of 2,563
 
I agree with you that measurements do not tell the entire story and there is no point to going only by numbers.    
 
However, there usually *IS* a relationship between measurements and the sound, and for a new headphone, i think a critical discussion of how the headphone measures is very valid.  

 
My point was that some of the discussion about measurements has come without the headphones being on hand, which has gotten out of hand. We've now have a single anomaly in the measurements, that, in the end, turned out to be from the measurement set-up, being called a defect in the headphones. It's not about getting defensive, it's about being sensible.
 
I learned about this long ago in different circumstances. At a party with my friends in high school, one of my good friends was absent. A discussion of which friends he confided in turned into a massive drama, with people accusing him of betrayal. This was purely because in his absence he was unable to set things straight. I've seen the same thing happen to both myself and co-workers, when the absence of a person result in them being demonised over nothing, or a misunderstanding. Substitute a product not in our possession and a bunch of graphs that might (or might not) show a problem and we have the same thing. This is why I wrote in the Posting Guidelines:
 
 [P]lease avoid trashing equipment you haven't used or aren't familiar with

 
There is a difference between saying "I am worried about X I in a measurement." and saying "The headphone has a problem because of this graph." when you don't have the headphones. Now we know one possible "problem" was a measurement anomaly.
 
  For example, I can look at some measurements and know for a fact that the product isnt for me - that saves me paying for the product and the cost of customs/postage to have it sent to me.    

 
You may be able to do this (I could do this with headphones that have certain characteristics too) but a lot of people can't, or end up reading too much into it. Again, I'm not saying don't discuss it, I'm just saying, don't write this stuff as some kind of absolute truth because of graphs without actually listening as well. A lot of this stuff is going to be more severely affected by people's musical tastes and how loud they listen, both of which are actually more critical to begin with.
 
Apr 16, 2014 at 10:02 AM Post #1,479 of 2,563
   
Wait, what speakers have you measured that have a cleaner decay around 200-300? How did you even reliably measure that low? It's certainly worth it to take CSD results in headphones below a kilohertz with a huge grain of salt. The 6% THD would likely be audible as a change in timbre for a critical listener provided they are familiar with the source recording (richer but fuzzier vocals, that sort of thing). It's not a deal breaker, but it is a problem.

 
I meant the THD. Sorry about the confusion due to my word choice. What I meant was not actually "ringing" or resonance, which is a linear phenomenon, although it can induce nonlinear distortion. Of course, CSD obtained from an impulse measurement with gating is not reliable in lower ranges.
 
Apr 16, 2014 at 10:06 AM Post #1,480 of 2,563
 
On a side note, it seems to me more and more that people tend to get VERY defensive the moment someone says anything critical of a product.   Take the original discussion - no one had a problem when there were pages and pages of posts going "oh, it is going to be fantastic" or similar stuff with absolutely NO basis in reality.   On the other hand, all it took was a couple of people to point out specific, fact-based issues (or potential issues) with the headphones and suddenly, the whole hive erupted.     What happens is that any critical comment or deviation from group-think gets shouted down/out and the people making those comments are made to feel responsible for derailing the thread - which, IMO, does a disservice to the head-fi community in the long run.

 
 
This is a VERY good point, with which I can't agree more.
 
Apr 16, 2014 at 10:28 AM Post #1,481 of 2,563
   
My point was that some of the discussion about measurements has come without the headphones being on hand, which has gotten out of hand. We've now have a single anomaly in the measurements, that, in the end, turned out to be from the measurement set-up, being called a defect in the headphones. It's not about getting defensive, it's about being sensible.
 
I learned about this long ago in different circumstances. At a party with my friends in high school, one of my good friends was absent. A discussion of which friends he confided in turned into a massive drama, with people accusing him of betrayal. This was purely because in his absence he was unable to set things straight. I've seen the same thing happen to both myself and co-workers, when the absence of a person result in them being demonised over nothing, or a misunderstanding. Substitute a product not in our possession and a bunch of graphs that might (or might not) show a problem and we have the same thing. This is why I wrote in the Posting Guidelines:
 
 
There is a difference between saying "I am worried about X I in a measurement." and saying "The headphone has a problem because of this graph." when you don't have the headphones. Now we know one possible "problem" was a measurement anomaly.
 
 
You may be able to do this (I could do this with headphones that have certain characteristics too) but a lot of people can't, or end up reading too much into it. Again, I'm not saying don't discuss it, I'm just saying, don't write this stuff as some kind of absolute truth because of graphs without actually listening as well. A lot of this stuff is going to be more severely affected by people's musical tastes and how loud they listen, both of which are actually more critical to begin with.

 
Currawong, I think a reasonable person should have no problem understanding what you are trying to convey. Your take on this is not loosely ground. I think it is merely a perspective difference, not a fundamental difference.
 
No one who has measurement experiences states that any kind of association between measurement results and subjective listening is absolute truth. One thing I agree about is that it may be too much for average readers without technical background to understand discussion about measurements. Obviously, such knowledge requires quite a bit of a earning curve. But just as some (but not all) people want to hear opinions about headphone users's subjective impressions, some (if not all) of them want to hear opinions from knowledgeable people who CAN associate measurements and perceived sound based on experience. With respect to reliability (I am talking about statistical reliability, not a vague term), I firmly believe that the latter is much more reliable. One may doubt validity of such information sources, but the judgment is ultimately the readers'.
 
Apr 16, 2014 at 10:43 AM Post #1,482 of 2,563
 
I don't think it is unfair to say something like "This graph/plot is interesting and a wonder if feature X on it is going to mean a problem with [some or other aspect of] the sound" but the way I've seen some people phrase things (eg: Talk of ringing at 200 Hz meaning a pair must be defective -- I mean really?) is getting a bit over the top. 
smile.gif

 
Sure, when I talk about measurements, I usually add carefully chosen qualifiers so that they may not be misinterpreted. But as a human, I sometimes forget. There is background when I said the pair might be defective. I have seen no planar-magnetic headphones (which cost several hundred dollars) that exhibit 5% THD at 200 - 300 Hz. People just do not know how much this amount of distortion is, and that is why I gave an example. That kind of interpretation of measurements is useful information for people without much background.
 
Apr 16, 2014 at 12:06 PM Post #1,483 of 2,563
  Again, I'm not saying don't discuss it, I'm just saying, don't write this stuff as some kind of absolute truth because of graphs without actually listening as well. A lot of this stuff is going to be more severely affected by people's musical tastes and how loud they listen, both of which are actually more critical to begin with.

 
Fair enough - no disagreements here.  Maybe it is just me, but i get the feeling that sometimes, even when the opinion is being stated as a warning as opposed to a definitive assertion, some people get upset (the X5 thread is a great example - post something that you dont like about it and you get called a whiner/attention seeker or stuff like that).    But i guess that may have something to do with the demographic of the forum.
 
Anyway, i think your solution of splitting the thread works - perhaps that is a model to follow for other, popular products.
 
Apr 16, 2014 at 12:14 PM Post #1,484 of 2,563
   
Currawong, I think a reasonable person should have no problem understanding what you are trying to convey. Your take on this is not loosely ground. I think it is merely a perspective difference, not a fundamental difference.
 
No one who has measurement experiences states that any kind of association between measurement results and subjective listening is absolute truth. One thing I agree about is that it may be too much for average readers without technical background to understand discussion about measurements. Obviously, such knowledge requires quite a bit of a earning curve. But just as some (but not all) people want to hear opinions about headphone users's subjective impressions, some (if not all) of them want to hear opinions from knowledgeable people who CAN associate measurements and perceived sound based on experience. With respect to reliability (I am talking about statistical reliability, not a vague term), I firmly believe that the latter is much more reliable. One may doubt validity of such information sources, but the judgment is ultimately the readers'.

 
I think this sums it up accurately in terms of this not being a disagreement in principles but merely how one interprets a certain post/writing style and/or where one draws the line between "bashing" and "critiquing".    
 
Using Jay's example earlier - i think most people would realize that he wasnt bashing so much, as making a statement based on the published measurements:   I dont remember how it was worded, but when i read it, it didnt strike me as being a "dont buy this headphone, this sucks" kinda post but a "whoa, there is something off about this measurement that bears more study".    A healthy discussion on the validity of those measurements (accuracy of testing, reliability of protocol, etc) would be more productive than eschewing that discussion altogether, IMO.   
 
Anyway, back to the Oppo.   Mine should get delivered to my freight forwarding address in a day or two, and i should get it by early May.    Will post my thoughts here.
 
Apr 16, 2014 at 12:29 PM Post #1,485 of 2,563
   
I meant the THD. Sorry about the confusion due to my word choice. What I meant was not actually "ringing" or resonance, which is a linear phenomenon, although it can induce nonlinear distortion. Of course, CSD obtained from an impulse measurement with gating is not reliable in lower ranges.


Ah, my mistake, should've grasped the context.
 
 
I have seen no planar-magnetic headphones (which cost several hundred dollars) that exhibit 5% THD at 200 - 300 Hz. People just do not know how much this amount of distortion is, and that is why I gave an example. That kind of interpretation of measurements is useful information for people without much background.

Check out the HE400. While the nonlinear distortion from the graphs is apparent if you look for it, it manifests as a mostly benign flavor in casual listening. Despite its ghastly looking graph the 400 is a terrific sounding headphone, I have no qualms recommending it to others.
 

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