Yggdrasil A2 Measurements - Deconstructing ASR / Amir's Hack Job

Discussion in 'Source Measurements' started by purr1n, Jun 7, 2018.

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  1. bobsherman

    bobsherman Acquaintance

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    Before becoming the grand mystic ruller he is now, the amir began his ass-ent to star-dumb as Major Tom.

     
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  2. Torq

    Torq MOT: Headphone.com

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    Personally, I really enjoyed the not-yet-called-out irony in Amir insisting he didn't think it relevant to measure the Yggdrasil's balanced outputs (or at least not to publish them), but making DAMN SURE he did for the Benchmark 3.

    Double standards and hypocrisy are excellent indicators of bias.
     
  3. ultrabike

    ultrabike Measurbator - Admin

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    Amir gives me the impression of a very energetic and motivated upper manager that fashions himself as an engineer. A bad combination.

    From a corporate perspective, he claims responsibility for the development of the Zune player, which sucks: https://www.engadget.com/2007/01/20/microsoft-made-the-zune-because-partner-hardware-sucks/

    He also claims responsibility for the development of WMA and a bunch of different DRM stuff, along with Windows Media Player all of which suck:
    https://www.linkedin.com/in/amir-majidimehr-0014a75/

    He has a very high and perhaps comical opinion of himself:
    "I started Madrona Digital after getting frustrated with working with the local companies on the control and entertainment aspects of my new home due to their low level of technical knowledge."

    Putting people down to propel himself up.
     
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  4. dmckean44

    dmckean44 In a Sherwood S6040CP relationship

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    He also claims responsibility for HD-DVD, which fell flat on it's face. If he was management at the time, he's probably responsible for there ever being a high def format war in the first place.
     
  5. Clemmaster

    Clemmaster Friend

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    Everything he did at microsoft, for audio, ended up DEAD. He's a failure.
     
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  6. svperstar

    svperstar Acquaintance

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    I just recently stumbled onto all of this and I just want to say I love Amir for no other reason then all of this drama has been highly entertaining to read. lol.
     
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  7. astromo

    astromo Rando

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    Then you'll love the added enjoyment that has been worked up over at his site where there's a comparison done against the results posted by @atomicbob

    I'll leave it to others with better knowledge than myself but I thought I could see (quick glance) a difference in measured values, even though the graphics appeared to have similar shape. I'm not convinced that there has been a valid cross-validation.
     
  8. ultrabike

    ultrabike Measurbator - Admin

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    Oh FUCK!

    "As you see, his "FFT meters" are declaring that there is 121+ dB of Signal to noise ratio. That data directly conflicts what the FFT is actually showing."

    Blah blah blah. Plot. Blah blah blah.

    "The dedicated meter in Audio Precision is reporting about 60 dB of dynamic range above our noise and distortion which matches more or less the manual math I performed on AtomicBob's graph."

    All here in ASS-R:

    https://www.audiosciencereview.com/...hiit-yggdrasil-v2-dac.3607/page-22#post-88259

    That is not Dynamic Range you moron! Read this page 2 of this Intersil app note:

    https://www.intersil.com/content/dam/intersil/documents/an97/an9789.pdf

    Here. Let me hand guide you child:

    Dynamic Range

    Dynamic range, or DR, is a ratio of the greatest magnitude(undistorted) signal to the quietest(discernable) signal in a
    system as expressed in dB. For audio applications, DR is a ratio of the full scale RMS signal level to the RMS sum of all other spectral components over the specified bandwidth using a -60dB FS amplitude signal. DR differs from SNR in that a -60db FS signal is used. To refer the measurement to full scale, 60db is added to the resultant measurement. In this way, the device is being excited, but the harmonic components, which are generated with a full scale input, are now typically well below the noise floor. DR is often used to estimate SNR. However, if a device operates in such a way that the level of the noise floor increases with increased input level, then a measure of the Dynamic Range is no longer a good estimation of the actual SNR.

    EDIT: This is an example of what really annoyed me about Amir's post:

    "As usual, his charts are impossible to read."

    "The meter used in AtomicBob's graph to derive the Signal to Noise ratio is simply wrong and not configured correctly."

    He is basically pissing on Bob. And doing so w out proper understanding of the measurements in question. This is an example of Amir jumping the gun for not so noble purposes, and doing so completely wrong. He is going to be called on it.
     
    Last edited: Jul 24, 2018
  9. atomicbob

    atomicbob dScope Yoda

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    I say more Schiit, less shit (you all know what and who I mean.)


    This is yggdrasil A2 rather than jotunheim and probably should be moved to a different thread, but the principles of borked measurements by the A-man apply. More context in post by @ultrabike above .

    Oh and for benefit of the audience (A-man doesn't appear to read standards) directly from AES17-2015

    6.4.1 Dynamic range

    This test measures the ratio of the full-scale level at the output of the EUT to the weighted noise and distortion level in the presence of a low-level signal. It includes all harmonic, inharmonic, and noise components. NOTE This characteristic is also known as signal-to-noise ratio. The test signal shall be a 997 Hz sine wave with a level of -60 dB relative to the maximum input level (see 6.2.1). The output of the EUT shall be filtered with the standard low-pass filter (see 5.2.5) and the standard notch filter (see 5.2.8), whose center frequency is set to 997 Hz. The output of the standard notch filter shall be filtered with the standard weighting filter (see 5.2.7). The rms level of the final filter output shall be measured. The dynamic range shall be the ratio of the maximum output level (see 6.2.6) to this measured level. It is reported as dB CCIR-RMS.

    Now here is the graph to which A-man refers in his rant:

    Dynamic Range
    20180219-14 Yggdrasil Bal dynamic range - spdif.PNG

    Reading the AES17-2015 method above this graph shows stimulus set at -60 dBFS as described. All the noise spurs are below -120 dBFS but when summed correctly (must convert from log to linear before adding and result converted back to log) a result of -62.2 Left and -61.2 Right dB below -60 dBFS is obtained. Then, and this is very important, it is necessary to add 60 dB, given use of a -60 dBFS signal from MAXIMUM OUTPUT LEVEL, as described in the AES17-2015 method for Dynamic Range above. The meters accurately report the final result.

    A-man missed this final step and proceeded to declare the dScope misconfigured. Also hard to read. No bother to fact check, read standards, consider that his thinking might not be correct. Nope, it is always someone else that is wrong. Never mind being at odds with the entire AES and EE community.

    Sorry A-man, you borked it again.

    So anything A-man has to say about any measurements should be viewed with a high degree of skepticism as he demonstrates with this rant his misunderstanding of standard measurements, and unwillingness to fact check before launching into immediate discredit mode. He has only managed to discredit himself.

    *edit* to provide better context
     
    Last edited: Jul 24, 2018
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  10. atomicbob

    atomicbob dScope Yoda

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    Provided more details about borked measurements above .
     
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  11. Biodegraded

    Biodegraded Friend

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    Well, obviously he missed that only because your graphs are so hard to read!

    Seriously though, maybe his prescription is old? Evidently he missed 'click this image to show the full-size version', as well as the text above the extra hole in the front of the iFi unit. Guess there's no chance he'll be able to read this bit either...
     
  12. purr1n

    purr1n Finding his inner redneck

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    On Amir using @atomicbob's measurements as of late:

    He is using misdirection again. No one here is disputing the higher distortion, the "multibit harmonics" of Schiit's or others' multibit DACs, compared to delta-sigma designs. For many of us here, (16-bit limit of -96.35db) it's good enough. For others, on ASR, it may not be, or it's a "total rip off". Fine. To each his own.**

    The disputes were always about the measurements that Amir severely borked on the Yggdrasil A2 that three other people (Bob, Jude, and myself) did not get: 1) 60Hz hum, 2) excess high distortion, 3) shelved frequency response below 200Hz, and 4) early deviation from linearity. Amir never responded to these.*

    In addition, Amir also hid Topping results that showed 60Hz harmonics. Note that my own results for Modi 2U vs Topping D30 in an attempt to replicate Amir's were also different, slightly in favor of Modi.

    The essential problem with Amir is his opportunistic style combined with his bias and improper or hasty operation of his measurement gear. Amir shows or hides measurements (borked it not) only when they suit the narrative he wants to present. Amir doesn't consistently present a standard suite of measurements, like @atomicbob with DACs, or I will headphones. Neither @atomicbob nor I show you only want we want to show you because we happen to like or dislike a vendor's product.

    *A simple "I screwed up" would have sufficed, but that would have dented the image of infallability that Amir wants to portray. (Kind of scary if you think about it.)

    **It's interesting that Amir isn't chasing after multibit DACs in general; but chooses to pick on Schiit.

    Let's also not forget the "Amir hum issues" on Jotunheim. x2 Jots from me and x1 from @atomicbob do not exhibit these results.
     
    Last edited: Jul 24, 2018
  13. ultrabike

    ultrabike Measurbator - Admin

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    Moved Amir's Yggdrasil Dynamic Range brain fart discussion here.
     
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  14. Screwdriver

    Screwdriver Rando

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    I will say y'all are calm over here.....The squirrels on ASR are rattling the storm doors and scaring the young'uns.
     
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  15. Elnrik

    Elnrik Super Friendly

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    The nut lovers can go climb a tree.
     
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  16. astromo

    astromo Rando

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    @atomicbob thanks for sharing the excerpts of AES17-2015. I can only locate old versions of that standard, so my reference point is dated.

    One of the critical shortcomings with the "analysis" over at ASR (unless I've missed it) is a lack of reference to recognised standards - be they industry, national, international or vendor based. If that was evident, I might be less sceptical of reported results and associated claims.

    Thanks for sharing some real audio science.
     
  17. msommers

    msommers High on Epipens

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    I'm glad you guys know what you're talking about and can lean on you for this technical expertise. Someone PM'd me the other day asking about my PS DSJr. vs. Yggdrasil A2 and mentioned poor measurements of the latter from Amir. Given your guys' knowledge here, I could easily tell this person to promptly avoid anything Amir states.

    So as much as I mentioned before "why talk about Amir because he's an idiot", I take that back given he really is swaying people's opinions of products.

    So thank you.
     
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  18. Screwdriver

    Screwdriver Rando

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    There are posts on ASR where people liked a DAC they own, found ASR and now want to sell it because it tested poorly. I don't know for a fact, but my Spidie Sense tells me that Schiit has probably lost sales because of Amir.......Yet, I also bet Topping has made a killing off his test. And if he is off on his tests, who is to say that the Toppings deserves it.
     
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  19. wormcycle

    wormcycle Friend

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    Hey if anyone there wants to sell high end Schiit DACs I am buying, the worse measurements the better the price I guess.
     
    Last edited: Jul 26, 2018
  20. insidious meme

    insidious meme Ambivalent Kumquat

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    Hard to do when they're nut hugging Amir over there.
     
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