"Ortho Wall" for lack of a better term

Discussion in 'Measurement Setups, Systems, and Standards' started by purr1n, May 19, 2016.

  1. purr1n

    purr1n Desire for betterer is endless.

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    Most planars have some tension to the diaphragm. In the case of orthos (SE or not), there's something on the CSDs which show how tightly tensions the diaphragms are. If you guys remember, I did an analysis of the LCD3 a while back, comparing "veiled" LCD3s to "good" LCD3s. I've also added an HE-400 CSD measurement for better comparison. Gurubai (the resident ortho expert) among others surmised that the "Ortho Wall" ringing was probably indicate of the diaphragm. Whatever it is, I think it's safe to say that this "wall" can be seen on ortho CSD measurements.

    The most crucial point I will make is that I don't hear any of of this "ortho wall ringing" with any of the headphones below. I mean I would hope that none of us here look at the LCD3 CSDs and go "Wowza! POS! OMG! WTF for $2000?" (And it's certainly possible that some people might hear this more than I can.) As John Atkinson pointed out in his PPT slide at THE SHOW 2012: "Measurements Lie." Now what's interesting is that flat plate coupler will push down the ortho wall, in some cases, making it not visible in the current CSDs with a -36db floor. An open or semi-open foam coupler will tend to make the effect more visible.

    The results (and subjective impressions) would certainly jive with Joe's (JPS Labs / Abyss) explanation to me:

    With CSD's, we've found the decay around 8-9 kHz to not be the driver, but acoustics. I chased this down for quite some time when going through various gasket materials and cut dimensions just to find I was chasing a ghost; taught me all about the wonderful world of CSD's-:)

    Or this one (from a post deleted from HF):

    In fact, I chased the CSD's for a good week or so prior to release only to come full circle to determine that this measurement, at least as it pertains to this design, was of no use in improving upon the final sonic character...

    Examples of the "Ortho Wall":
    he-4007b9c.png
    x Abyss Rce10.png
    LCD3g2 L.txt3df4.jpg
    LCD3n2v R.txt18b4.jpg
     
  2. Armaegis

    Armaegis Friend

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    Have there ever been manufacturer comments on diaphragm tension and how it moved (if at all) the wall?
     
  3. n3rdling

    n3rdling Friend

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    Does the wall change (shift or amplitude) with different couplers? Different model mics?
     
  4. purr1n

    purr1n Desire for betterer is endless.

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    Lower amplitude with sealed coupler. Higher amplitude with open or semi-sealed. FR doesn't seem to change.
     
  5. n3rdling

    n3rdling Friend

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    Interesting. Are there any orthos that don't exhibit this behavior? Any that are extreme?
     
  6. Maxx134

    Maxx134 Dunning–Kruger effect poster boy

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    I have experimented on the HEKV2 and found the diaphram seems also have an acoustic air pressure tension from the internal clamp made by the pads to ear,
    so I have relieved this pressure to note tonality and soundstage dimensionailty has increased,
    causing me to wonder if this altered the "ortho wall" effect,
    but then I realize the "ortho wall" seems dependant on actual surface reflection/absorbtion of the face and diaphram resonance/ringing right?
    I assume the sonic effect of ortho wall would be an overall coloration or added tonality which I wonder if double sided magnets would control better than single sided designs.

    In any case, the sensitivity and congested or pressure/air damping effect of the HEK pad to head, is probably due to diaphram being more sensitive and thin.
     
  7. nobodyNoot

    nobodyNoot New

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    Yea, I've noticed velour earpads on my two planar cans (Fostex mk3 and 400SE) increased not only the soundstage width but also lifted the veil on a lot of microdetail that wasn't there before, which also made 3D spatial positioning that much more accurate... (I use this nifty Unity demo i downloaded from here: http://matthewkerswill.com/creative-work/realspace-3d-audio-demo/ )
    Only downside is it also made them that much more sibilant in the mid-highs, which my cat-ears don't like >w<)
    Surprisingly tho, despite what measurements online seemed to indicate, there was also a noticeable INCREASE in Bass, I'm assuming from the increased forward driver excursion.

    A good compromise between smoothness and clarity are actually these fluffy sort of "Replacement Bevel Long Velvet Cushion" earpads i found on AliExpress:
    [​IMG]
    The fur extends halfway down then it's leather again, but that leather has 6 perforations spaced out in a circle all around its circumference, which lets the drivers flex outwards more and make the sub-bass feel Tangible.
    Unfortunately they're too warm to wear during summer and I don't have Air-Conditioning xC
     
    Last edited: Jul 22, 2021
  8. Woland

    Woland Friend

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    Did you notice you're replying to a discussion from early 2016...?
     
  9. Elnrik

    Elnrik Super Friendly

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    Let the necromancer do his thing.

    All he wants from life is to raise a family.

    Buh dum tiss...
     
  10. rhythmdevils

    rhythmdevils MOT: rhythmdevils audio

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    Another perspective… I hate those pads on every ortho I’ve tried them on. Closed in and dull.
     
  11. dBel84

    dBel84 Friend

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    The premise of the original discussion was a good one. So many interesting experiments to consider when investigating this phenomenon and not untimely with much of the discussion being generated around orthos at the moment.

    dB
     
  12. Philimon

    Philimon Friend

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    That might mean more damping (tightening up airflow to restrict driver movement) results in less ringing.

    Which ortho / planar have the cleanest CSDs? What patterns might we find? So many variables…

    A fun trial would be incremental CSD measurements of an increasingly dampened driver.

    Assuming low driver ringing would need high damping (amount dependent on driver etc), then you would lower the amount of excursion that driver can achieve which would result in less bass spls and/or macrodynamics (there are plusses but ignoring for moment). So many variables. To counter this you would need a larger driver that wouldnt need to move as much to produce those lower tones louder. Makes sense, aligns with general dynamic driver rule: larger diameter driver equals less distortion and more bass etc.

    Then then are design goals which can be limited by costs etc settled by preferred compromises. Very vague because Im very guessing.

    And then in dynamic drivers you have different cone materials which effect much. The vintage JBLs I just picked up have 15” woofers made of paper, they sound quick (but at what costs). My Manzanitas have 15” woofers that are much thicker and denser and they sound much less micro and macro dynamic but sound more even and work in an open baffle. So many variables. There are probably tons of books that we can read about speaker design, but how much translates to headphone design and particularly planars.

    I am obviously way over my head. Just want to try and spur discussion. Reading textbooks or even diyaudio is so boring because im dumb.

    @dBel84 mentions recent ortho / planar activity, because there is a headphone on loaner tour that has two versions which are identical except for the driver membrane. The different driver membrane material is tensioned to a different amount for whatever reason. What can be gleaned from comparisons. The headphone in question is the vintage ortho NAD RP18 / Fostex T50.

    There is some discussion about planar CSDs in these threads.:

    https://www.superbestaudiofriends.o...-hifiman-he5xx-review-and-measurements.10082/
    https://www.superbestaudiofriends.o...all-of-he-5xxs-bullshit-that-i-noticed.10120/

    ^ @takato14 is the only person I know of who has extensive experience with both versions of vintage T50. Fun to speculate.

    Could lessons learned by vintage ortho manufacturers benefit today’s renaissance. We saw Final Audio appear to source vintage ortho engineers and stamping to make their D8000. We saw Hifiman continue to push the envelope on driver membrane thinness to mixed results. We saw Verum go the opposite route and went thick and loose to interesting results, @Voldemeort himself saying that thick and loose is just more reliable … vintage orthos are a testament to that.

    @rhythmdevils is the resident planar historian and has heard more planars than all of us here. Would love for him to think out loud on the subject.
     
  13. Philimon

    Philimon Friend

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    I remember @purr1n modded the Verum One by removing 1/2 layers of felt damping. Was there a shift in the CSD measurements? What about burst response? Etc
     
  14. rhythmdevils

    rhythmdevils MOT: rhythmdevils audio

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    I'm definitely not, @dBel84 and @gurubhai are brilliant. The 3 of us should be seen as equals. They just aren't as active modding anymore and have settled with vintage orthos and I'm still obsessed and relentlessly trying to reach nirvana through making the perfect ortho. But the two of them actually probably know more about the history than I do. And @dBel84 has more technical understanding of ortho drivers than I do.

    My understanding is more intuitive and non verbal. I get feelings and hunches about what to do based on my experience. Ideals just come to me. But the three of us used to have long chats about ortho modification and we all see things very similarly, and they're both two of the most knowledgeable people in the world about orthos.
     

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