"Ortho Wall" for lack of a better term

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

  1. purr1n

    purr1n Finding his inner redneck

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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
     
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  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?
     
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  4. purr1n

    purr1n Finding his inner redneck

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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?
     
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  6. Maxx134

    Maxx134 Friend

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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.
     

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