Russian measurement site

Discussion in 'Audio Science' started by Madaboutaudio, Sep 24, 2016.

  1. Madaboutaudio

    Madaboutaudio Friend

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  2. Dreyka

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  3. T.Rainman

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  4. sorrodje

    sorrodje Carla Bruni's other lover - Friend

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    Headphone ones look like a mix between uncompensated measurements on a dummy head and usual uncompensated ones on a flat coupler.

    As long we don't know how are built those results, they mean nothing imo.

    a LCD3 looks almost bright :

    [​IMG]



    All measurement show a somewhat normal 20hz to 1/2 khz region and then an odd elevated treble compared to usual measurements ( Tyll's compensated ones or SBAF ones)
     
  5. Hrodulf

    Hrodulf Prohibited from acting as an MOT until year 2050

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    Compare only within the same system. That's the rule of thumb.

    With that said, their compensation isn't too off.
     
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  6. sorrodje

    sorrodje Carla Bruni's other lover - Friend

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    I know the rule thks ;)

    [​IMG]

    Looks like something uncompensated or partially compensated for me. if those are compensated, I'd like to see raw takes as tyll usuall does.

    Same for HD600 . whole treble Looks weird for me.

    [​IMG]


    Compared to each other the two FR makes sense though. :)
     
  7. romanrex

    romanrex Rando

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    Yes, the first measurement was made on personalaudio.ru. Now it is a separate site with new measurements and graphs. For older measurements based personalaudio.ru on the reference-audio-analyzer.pro added additional graphics.

    English version reference-audio-analyzer.pro coming soon
     
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  8. T.Rainman

    T.Rainman Acquaintance

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    When they would apply about 2dB more compensation between 2kHz and 5kHz I think the plots portray pretty well how I hear them.
    They are the first to measure all the way up to 40kHz (for what that's worth) ?
     
  9. anetode

    anetode Moderator

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    Judging from the bass measurements they don't worry too much about getting a proper seal.
     
  10. landroni

    landroni Friend

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    This is their FAQ on headphone measurements (in Russian of course):
    http://personalaudio.ru/detail/tekhnicheskie_stendy_dlya_izmereniy_naushnikov/

    From a cursory look, the stands used are either according to GOST 28728-89 standards (that seems to have been enacted in '89 USSR) or IEC 60268-7 standards. In terms of software they use RightMark Audio Analyzer (RMAA), ARTA and Reference Audio Analyzer (RAA). The FAQ itself was written in Dec 2012.
     
  11. sorrodje

    sorrodje Carla Bruni's other lover - Friend

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    If someone can sum it up accurately it could be helpful. Google translate won't really help on that one.
     
  12. landroni

    landroni Friend

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    Is there something specifically of interest? They don't seem to be talking about nitty-gritty details like compensation schemes. In the software section they just list the programs with very general advantages/disadvantages notes. They do talk more about the headphone stands though...
     
  13. sorrodje

    sorrodje Carla Bruni's other lover - Friend

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    What they used as compensation was what I was looking for . :)
     
  14. landroni

    landroni Friend

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    Right, compensation...
    http://reference-audio-analyzer.pro/amp_comp.php


    Compensation for the influence of the amp when testing headphones using RAA

    Just like the headphones, the amp has its own resistance*. Often, ignoring this factor, when assessing the same pair of headphones the listeners may end up with opposing conclusions on how they sound, concerning their loudness and frequency balance, and the measured headphones superficially exhibit differing FR in identical conditions.

    In a simplified state the electrical scheme contains the source for the charge and two subsequent resistances, one which is the equivalent of the internal resistance of the amp `R (Amplifier)`, and the other the equivalent resistance of the headphones.


    [​IMG]

    When connecting to amps with different output resistance, the FR lowers in level, however the lowering is not constant, in the lower-end register of the frequency band the lowering is maximal, in the higher-end it is less important.

    Thanks to the algorithms in RAA when measuring headphones we compensate the effect of the change in FR from the measured parameters of the amp.

    In the measurements up to 2015 for amping duties we used E-MU1616m, ESI U24XL and ASUS Xonar U7. In all the reports we used the corresponding FR compensation.

    To learn more about the influence of the impedance* of the headphones and amp on the FR check out the Reference Audio Analyzer docs [all links in Russian]:
    http://geektimes.ru/company/soundpal/blog/243447/
    http://geektimes.ru/company/soundpal/blog/248688/
    http://personalaudio.ru/detail/impedans_naushnikov/



    * I should note that in the first case, 'resistance', the Russian word сопротивление is literally translated like this. It might have meant 'impedance', but I don't know. If the prose doesn't make sense to you, substitute "resistance" with "impedance".
     
  15. Drakkard

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    The main cause of this curves is his dummy head. He has medical artificial ears glued on the mannequin, and microphones are installed inside them. So middle ear is not simulated, only outer ear. This artificial ear is also the cause of bad fit of some headphones, which author knows about.
    On some older measurements, he also used flat stand, to highlight a possible bass issue on the first stand. Not sure why he does not use it now.
    For example here - http://reference-audio-analyzer.pro/report/hp/bower-wilkins-p5.php
    HDM1 is the head mannequin, and SF1 is flat stand.

    As I remember, author does not use any additional compensation curves.
    @sorrodje if you want to know something in particular I can ask him directly
     
    Last edited: Dec 28, 2016
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  16. Drakkard

    Drakkard Acquaintance

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    This is the explanation of the feature of the RAA, which simulates the change in FR on amplifiers with different output resistance. It is not the compensation curve he applies to raw FR measurement.
     
  17. sorrodje

    sorrodje Carla Bruni's other lover - Friend

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    Nah Thks. You gave all explanations needed.
     
  18. Drakkard

    Drakkard Acquaintance

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    Ок :) I have a feeling that his system shows 500-3000hz range the most closer to the truth. Meaning that what subjectively perceived as flat, is also flat on the graphs. Higher frequencies are questionable, however.
     
  19. sorrodje

    sorrodje Carla Bruni's other lover - Friend

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    @Drakkard Seems we agree ;)
     

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