Audio Zenith PMx2 Redux and Quick Impressions

Discussion in 'Headphone Measurements' started by purr1n, Sep 28, 2015.

  1. purr1n

    purr1n Finding his inner redneck

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    12/20/2016 UPDATE: http://www.superbestaudiofriends.or...ux-and-quick-impressions.60/page-2#post-94971

    I'm a little bit late on this, but several months ago, OJ mentioned to me that I should definitely give latest new iteration a try. The jist of it was that Alex (of Audio Zenith) managed to get rid of a most of the PM-1/2's distortion characteristics. I was like whatever, BS.

    Well I'll have to eat my words on that one. I'll steal what Hands described as the "the neutral, generally easy-going tone" at Tyll's Big Sound. Those of you who have spoken to Alex knows that he places the highest priority on frequency response; and I believe that he has accomplished his goal. These are among the most neutral or flat sounding headphones out there with the least tonal issues. One area outside of frequency response where the PMx2 excelled was with transient response and separation in the treble. This can be easily heard with distinct hi-hat techniques where the separation of hits is distinguished rather than the bled together as heard in traditional dynamics. (Although I still feel the best dynamics resolve better.)

    [​IMG]

    I tried this headphone with the EC ZD Super (with a high 20 ohm output impedance, which is not optimal for this 32ohm headphone) and amazingly, the PMx2 didn't have too much of an issue with softness, probably because of the PMx2's super sensitivity. However, I felt the PMx2 was most at home being powered by the Ragnarok, where its extra power, especially into low impedance loads, offered a more slam, articulation, and sustain in the bass.

    There's nothing much else to say, mainly because there is nothing wrong with it. Measurements are forthcoming.
     
    Last edited: Dec 20, 2016
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  2. purr1n

    purr1n Finding his inner redneck

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    Figure 1: Frequency Response and Distortions of the PMx2 (0dBr = 100dbSPL)
    Note how the frequency response is smoother and distortion characteristics are far superior to the early development version of the PMx2 in Figure 3 (bottom)
    PMx2FR.gif
    PMx2 L HD.jpg
    PMx2 R HD.jpg

    Figure 2: CSD of the PMx2
    CSDs are spectacularly clean with no ringing and even decay.
    PMx2 left.jpg
    PMx2 right.jpg

    Figure 3: Frequency Response and Distortions of Early Development PMx2
    Note the early development PMx2 had distortion characteristics not much better than the stock PM-1/2. The peak at 8kHz is also sharper and does not integrate smoothly with the rest of the response.
    PMX.gif
     

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    Last edited: Nov 25, 2015
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  3. Colgin

    Colgin Friend

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    Is soundstage basically the same compared to earlier production version. I haven't heard the PMx2 in a while but the soundstage was already a significant improvement over stock PM-2 and was wondering if there was any further improvement or basically the same.
     
  4. purr1n

    purr1n Finding his inner redneck

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    It's the same as the development version. That is a significant improvement over stock. Lots of air (not reflected by the measurements) which helps the feeling of openness.
     
  5. Hands

    Hands Overzealous Auto Flusher - Measurbator

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    I still think some of the better dynamics and some planars beat it out with transient sharpness, general clarity, air, slam, dynamics, resolving power, etc. Well, usually I find planars to have too many trade-offs with most offerings available, so it's more like some planars beat it in some of those areas, depending. The PMx2 is just slightly soft sounding to me, maybe slightly overdamped. Still not nearly as overdamped as the stock PM-1 or PM-2 and not nearly as soft sounding (excluding PM-2 + stock pads treble etch...dark,veiled, and rough...yuck).

    But, seriously, I can't stress how damn neutral this is. Wonderful tone, even though I myself prefer a bit of extra bass like on the HD650. Yeah, OK, even considering the softness, it does a whole lot less wrong than the vast majority of headphones and runs well from about anything. Works best with a powerful sounding SS amp. I just happen to prefer the HD650 + a really good, powerful, airy tube amp over the PMx2, a combo which you can build for the price of or under the PMx2, but if I had to pick a 2nd headphone for general purpose, long-term-listening, it would probably be the PMx2. That said, if you're more an HD800 type of guy or are willing to sacrifice tone and frequency response for better technicalities, maybe the PMx2 isn't for you.
     
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  6. AustinValentine

    AustinValentine Friend

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    At the Tweak Audio Chicago meet, I got some strange looks when I said that I preferred the PMx2 out of the Yggy/Rag over a (stock) HD800, HE-1000, Ether, and the Pioneer dynamic headphone (the SE Master 1). I still stand by that. Sure, the PMx2 doesn't win on technicalities against a lot of the flagships, but it doesn't do anything at all wrong. It has fantastic tonal balance, impressive blackground, great transient response and AZ's modified pads are easily the most comfortable I've ever worn.

    The PMx2 + Yggy/Rag is probably the best hassle-free audio setup I've ever heard. No tubes to worry about. No DIY headphone modding involved. No worrying about vintage receivers, power amps, or pad swaps. Just plug in all of the components and call it a day.

    If I ever get tired of my HD800s (and I'm always on the fence about them), the PMx2's will probably be the next route I'll go.
     
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  7. Colgin

    Colgin Friend

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    I have the stock PM-2 and while I like a lot about it, let's face it it is not the most resolving headphone. For that I would think a good DAC such as Gumby might be overkill and not money well spent. Just wondering if a good DAC is more worthwhile for the PMx2 (or is it resolution limited due to the limitations of the drivers themselves) or would budget be better spent getting the best SS amp one can afford first with the DAC taking a backseat.
     
  8. keanex

    keanex Martian Bounty Hunter - Friend

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    The pmx2 are the most natural sounding headphones I've heard. I reviewed them on HF, but the gist of it is that I really like them. Easy going and very natural.
     
  9. Hands

    Hands Overzealous Auto Flusher - Measurbator

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    Look, just because the PMx2 might not be as sharp and resolving as an HD800, or sometimes even an HD650 with a good chain, doesn't mean it won't see gains from a better DAC and amp. The Yggy + Rag combo makes a lot of sense for the inherent PMx2 sound. Whether you should focus on the DAC or amp first, I don't know. Amp, probably.

    That said, they'll also sound pretty decent from a phone, so you can get away with that and not worry too much.
     
  10. zonto

    zonto Friend

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    Aren't the pads non-replaceable though? What happens when/if they deteriorate?
     
  11. Hun7er

    Hun7er Dolphin flipper

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    Hi,

    In which area the PMX2 is better than the HD650 ?
     
  12. keanex

    keanex Martian Bounty Hunter - Friend

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    Yes, that was troublesome to me as well. Not sure what'll be done when they do.
     
  13. Colgin

    Colgin Friend

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    Maybe AZ will chime in on this at some point. I do recall he did respond to this point at some time on either Chang or HF. IIRC I think his response was to the effect that pads should last a really long time and if they was an issue they could be sent back to him for fixing. Understand that his pads are special ones. It would be nice if they were user replaceable and then an extra set could be ordered at time of purchase and the user should be good for a long time. But I guess they must be glued in or something. If they were based on the fake leather I wouldn't be too concerned. But AZ works with the velour pads. I would expect those to degrade a bit over time with a lot of use. That said, I have had my Q701s for at least 3 years now and the velour pads still seem in great shape. But then again I don't use them every day and 3 years is still relatively short in the longterm scheme of things.
     
  14. purr1n

    purr1n Finding his inner redneck

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    Better quality less wooley bass. Faster more delineated treble.
     
  15. Hun7er

    Hun7er Dolphin flipper

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    Thank you Purrin. Seems pretty good as I like very much the HD650.

    Did you think it has more bass slam or more physical sound than the HD650 ?
     
  16. Audio Zenith

    Audio Zenith Custom Title KGB

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    Firstly I would like to express my appreciation for starting this thread. Secondly huge thanks to all who decided to chime in.

    Concerns about pads are understandable but, the way I see it sending headphones back at some point for replacement of the original pads could actually be a good thing. This would allow me to replace worn out ones with new perfectly matched to the set in it's current state. In other words, if any component inside somehow changes its original state call it break in or whatever, I would be able to remeasure and make it perfect once again.

    For the overdamping issue I can only say one thing, original OPPO diaphragm is fairly heavy and thick and physically needs more damping than any other ortho but I personally believe it to be one of the reasons why PMx2 sounds so incredibly organic and lifelike. It reminds me of Yggy after proper warm up when you can hear the unmatched liquid smooth and organic sound.

    Here are my 2 cents on the subject of technicalities and scalability. I could be biased since after family these are my life but what good would I be as a designer if I could not attest sound quality professionally and unbiased. Could I be lying to everyone not disclosing the issues I actually hear, read my posts on CS and you will get the idea. Can I simply be mistaken, everyone can.

    Suppose many of you know I value tonal accuracy the most and will take it over fake resolution any day. Correct timbre and tone are the essence of music. No good artist will EVER touch attuned instrument, let alone make a performance with it. What is the point of wasting time on listening to the voices/instruments being attuned/altered by the transducer? Headphone audio system is the same instrument but its main role is to ACCURATELY represent the recording.

    What is the point in a "hyper resolving" headphone whose frequency response has to be corrected by 6db in SEVERAL places going throughout the most sensitive areas of human hearing range? Why should we tolerate hearing Stradivarius violin represented sounding like a plastic Yamaha? How can we tolerate Steinway Grand represented sounding like an electric Roland? I personally can only accept true resolution which is fundamentally based on tonal/timbral correctness. Unfortunately most of the audio systems I personally have ever heard headphone or loudspeaker based were low resolution, to the point of not being able to listen to them at all. Moreover only 3-5% of all the recordings I go through end up being listened regularly, simply because I can not find satisfaction in the the way music on the rest of 95% is being resolved.

    As a matter of fact I feel the same about both recordings and transducers; sound engineers should first figure out how to make a perfectly neutral and transparent recording and only if/when succeeded can try with performing their own interpretations. I feel the right way would be to make two versions and let the listener decide which to prefer. Same goes to engineers of all the transducers, please give me the perfectly neutral signature first and then let's have fun with hyper resolution, elevated bass or treble or any other kind of cool staff. That IMO is the only right way everything in audio reproduction should work, not the other way around.

    Blah blah blah such a bs, no good recordings and no good systems, move to another planet you ....... ........! Right? Sorry, but wrong. When good recording is properly reproduced it sounds absolutely magnificent! Properly constructed system would actually be able to reproduce a content most would actually think is impossible to record! Unfortunately it is extremely difficult to experience just how much can a simple redbook CD hold in itself and what can be heard with a perfectly engineered audio system/listening room combo.

    I shall explain; some form of a mix between loudspeaker and headphone could be a perfect solution for ideal reproduction of properly recorded content. In such a system one will be able to hear both; perfect resolution of timbre and tone possible in ideal headphones ( this comes from the lack of interaction between sounds coming from left and right transducers) and perfect resolution of spatial content ( this comes from the proper interaction of ideal loudspeakers with the listening environment).

    It should be possible to actually hear/feel separate sound waves/air motion initiated in the listening room's specific locations by different instruments/voices perfectly resolved with absolutely correct tonality and this is not all! It should be possible to perfectly hear not only locations but also individual qualities of the microphones and other recording gear involved in the making of a given media. It should be possible to completely eliminate hearing dimensions and qualities of a given listening room but instead feel the correct air density and size of the recording venue. I believe something fairly close to such system actually exists and will try assembling it back in-time for the upcoming San Diego meet for pirates to hear but let's get back to the main topic.

    Subjective resolution of PMx2 vs HD-650 was checked by Hands and me at the 2015 RMAF where we tried to distinguish different power cords in a chain of a decent audio system. Power was distributed from a grid in Marriott hotel in a very complicated manner. Off the shelf extension cord was connected to a 4x splitter in a wall and then power went to off the shelf 6x power strip, after which into another off the shelf short extension cord and then into a power cord costing more than $1000 connected to LPS and then through umbilical cord into a DAC. Costing over $1000 each power cords were connecting other two components of that system. Tyll thought identifying specific sound signature of a power cord in such a mess would be ridiculous and I agreed but.... both me and Hands could do it blind with "unresolving" PMx2 in a noisy conditions of the largest US audio show.

    This experiment was never planned but here is how it happened: Someone at the beginning of the show on Friday has brought me for testing one fairly expensive looking power cord of unknown brand and price (at the end of a show I was told it's cost was $500.00 but brand is still unknown). Having similar reaction to Tyll's, first day I hesitated to test the damn thing but this was already a second show the man was asking for evaluation and Saturday morning I finally decided to give it a try. To my surprise difference between my own expensive power cords and this one was quite noticeable. I swapped them back and forth several times and finally had absolutely no doubts. Few hours later Hands stopped by my booth and I asked if he could help me out and do the same test. After some understandable hesitation he agreed and we started.

    Four swaps was enough to figure it all out and the sound character differences between expensive cables for Tyler were exactly the same with how I noticed them myself. Hands then had to continue with the rest of the show but came back right before the end. I asked to do the same test with HD-650s and 6 swaps later the winning power cord was chosen. This time though sound character variations Tyler described were different from what he and I experienced with PMx2 (this makes me a bit suspicious of the HD-650s but nothing is perfect).

    Despite all the craziness of the above test results IMO are quite telling, Hands was being able to pick the same power cord with both PMx2 and HD-650 headphones absolutely blind. This was my first time testing power cords but I honestly don't remember myself having problems telling apart interconnects and headphone cables from one another with PMx2 based on changes to the sound while blind. The only cables I actually have problems with are USB which I absolutely can not tell from one another.

    How much more of a resolution does one need in a headphone I simply don't know but for me personally PMx2 is more than enough in this department. Not sure if my own experience and the above test could be of any indication of PMx2s resolving powers but wish Tyll was to pick it for the Big Sound blind amp testing instead of HE1000s and feel that results could have been a bit different.

    The point is, maybe for true resolution we should look into headsets that are able to flawlessly reproduce midrange, the heart of music rather than fight with the ones suffering from treble spikes and other anomalies?
     
    Last edited: Oct 7, 2015
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  17. Hun7er

    Hun7er Dolphin flipper

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    I can't agree more with you Audio Zenith. Timbre and tones are the first thing in my checklist.

    About the pads, the issue is when you live outside USA, it's a bit laborious to send the headphone. But yes it's not amp.
     
  18. Cspirou

    Cspirou They call me Sparky

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    Impedance matching really isn't an issue with planar magnetic headphones. The impedance is purely resistive and doesn't have issues with damping that you would have with dynamic headphones. Also since the impedance is even across the entire frequency band, you don't get issues with impedance peaks causing differences between amps with different output impedances. That's why people report no real difference between the voltage and current output of the Bakoon amp when using a HiFiMan or Audeze headphones.
     
  19. Hands

    Hands Overzealous Auto Flusher - Measurbator

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    I actually would have preferred the PMx2 for the ortho blind test at Big Sound. The HE1K's tone gets in the way for me, and I am worried about some of its other characteristics being a limitation. Not that the OPPOs don't have limitations, but it always sounds like the PMx2 gets out of the way more than the HiFiMans. Maybe that's just me.

    Personally, with a really good amp on the PMx2 and HD650 (and both have different amps they match best with), I find the PMx2 is just a slight notch below the HD650 in terms of clarity and resolution. I am sure others that tend to prefer planars will hear the opposite, and that's fine. That said, the HD650 has a bassier sound and is technically less neutral, but I just so happen to prefer that mid-bass boost. I do rank tone higher than other technicalities, but I also just prefer the HD650's tone regardless. PMx2 does have better quality bass regardless of tone or neutrality, but it's not a massive difference. I really find the PMx2 to be perfectly competent and resolving for my tastes...just have a headphone I prefer more is all. It's just when speaking relative compared to other headphones, sure, even if some other headphones have weird tone, I do think there are more resolving, sharper sounding (in a good way) headphones out there compared to the PMx2 and even HD650 in some regards. But hell, they can be as resolving as possible, but if the tone isn't for me, doesn't matter.

    The power cable test was interesting. A big part of me felt like I was guessing, but some part of me thought I was indeed hearing very slight differences. Even though I did a couple more swaps on the HD650, more out of wanting to be sure and feeling less pressed for time, I did remark I thought the differences, if truly there, were more pronounced on the HD650 than PMx2. Though, apparently I heard the opposite effects between the cables on the PMx2 and HD650, but it's not the first time I've heard different headphones respond differently to different source components. I've never heard a PM-2 of any kind sound more different than out of a Lyr 2. Never thought an amp could make a headphone sound so much bassier than it really is! And yet it didn't do the same to the HE560. All comes down to matching, I guess.
     
  20. purr1n

    purr1n Finding his inner redneck

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    You are correct in that it does not affect frequency response because the load is purely resistive. However, damping factor does affect power delivery / non-linear distortion. Amps with higher damping factors will also better control ringing. Keep in mind that I said the PMx2 sounded soft with the ECZDS. I didn't say that the frequency response changed.

    The idea that damping factor (in relation to power) does not matter for orthos because of their purely resistive loads is a completely misguided notion, probably originating from HF.
     
    Last edited: Oct 11, 2015

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