MQA Review - Technical Analysis

Discussion in 'General Audio Discussion' started by Woland, Apr 15, 2021.

  1. Yethal

    Yethal Facebook Friend

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    In order for an encoding scheme to be lossless (or lossy for that matter) we first need to have a point of reference. When talking about compression schemes in audio the most common reference point used is the original .wav file exported from a daw at the end of the mixing/mastering and using that reference point flac is lossless as it allows us to reconstruct the original wav file whereas mp3 does not. As GoldenOne's experiment has shown neither does MQA as the MQA encoded flac will no longer reconstruct the original wav file (due to added noise).
     
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  2. crenca

    crenca Friend

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    *.wav is data chunking mechanism used to manipulate LCPM on data level:

    https://en.wikipedia.org/wiki/WAV

    So is .wav an audio encoder? Is not the PCM that is manipulated on a bit/byte level by .wav not that actual quantization of an actual (audio) pressure wave? If this is true, is said PCM lossy or lossless, and what does the .wav (as a data chunking/transmission mechanism) have to do with how we answer this question?
     
    Last edited: Apr 21, 2021
  3. Josh83

    Josh83 Friend

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    Haha. I don't want to get back into the "What is lossy?" question. I think I outlined what I mean by that before.

    But it's worth noting again that Golden's files were just edge cases. MQA went wild on a 1kHz sine.
     
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  4. crenca

    crenca Friend

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    You mean 1khz impulse response right? At what point in the video?

    Edit: I think you mean around 11:00 in the video. Yea that's fucked.

    Edit2: I see around 16:00 mark @GoldenOne points out how he has "musical content all the way to 22khz" (which, hard to tell from the video, looks like it is very loud) in his files. I imagine this is one thing John and Amir are jumping on - this sort of edge case/unnatural/"illegal" content. This will of course break MQA due to the slow roll off "min phase" filter it uses. It would also break regular PCM if you did not use a fast and/or "brick wall" filter, use more headroom (perhaps an 88.2 sample rate), etc.
     
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    Last edited: Apr 21, 2021
  5. spoony

    spoony Spooky

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    The DATA encoded in a FLAC file is lossless as compared to the original PCM-encoded digital file used to produce it. If the original SIGNAL was SAMPLED using another technology (obscure ADCs anyone?) and PROCESSED DIGITALLY without loss (information theory experts here?), then a CONVERSION to a PCM representation could entail signal reconstruction and possible 'loss' of information depending on the methods employed. According to the sampling theorem, PCM @ 44.1 KHz should suffice IF the psychoacoustic model for the 'audioband' is complete.
     
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  6. Josh83

    Josh83 Friend

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    I don’t know if I’d refer to a leaky filter as “breaking” PCM, but point taken. To me, the fact that the user is ultimately in control of filter choice is what makes it less of a concern with PCM. (I personally tend to prefer fast linear phase filters, though.) With MQA, the user locked into their filter if they want to get MQA’s “benefits.” If someone loves the iFi GTO filter, which seems really similar to MQA’s, that’s fine by me. Just don’t make me use it and tie it to a lossy format being sold as lossless.
     
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  7. SSL

    SSL Friend

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    Is it? From MQA: Questions and Answers Temporal Blur In Sampled Systems:
    That was written by Bob Stuart himself. So at least one person is confused in all of this.
     
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  8. Metro

    Metro Friend

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  9. Yethal

    Yethal Facebook Friend

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    What .wav has to do with it is that's the format uncompressed pcm is usually stored in after it has been mastered in the studio and that's the file format all other formats (such as flac and mp3 for streaming services) will be derived from.
     
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  10. bboris77

    bboris77 Friend

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    Like many of us predicted, intelligent ASR members have started calling Amir out on many inconsistencies within his own logic when it comes to MQA which has resulted in him losing some of his cultish aura.

    Huge credits to @GoldenOne for producing the straw that broke the camel’s back. That one video managed to expose Tidal, MQA and Amir all in one. Between this and what happened in the world of soccer with the Superleague fiasco, my faith in the future of the humankind has been restored :) There’s still hope for the little guy.
     
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  11. Thad E Ginathom

    Thad E Ginathom Friend

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    Please excuse a lighter moment.

    It brings to mind one of the greatest sketches by the great British commedians Morcambe and Wise, with guest star Andre Previn. This dialogue...

    "You're playing all the wrong notes!"

    "I'm playing all the right notes, but not necessarily in the right order."
     
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    Last edited: Apr 22, 2021
  12. Hrodulf

    Hrodulf Prohibited from acting as an MOT until year 2050

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    If Amir is on friendly terms with the Chinese number pumper firms, then it's it's pretty evident why he would defend MQA. ESS9068 is out and it's the first DAC chip with a MQA percolator baked in, and Gustard is already happily putting them in their stuff. Just a speculation, of course...

    Have you no shame?
     
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  13. Psalmanazar

    Psalmanazar Most improved member; A+

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    Meanwhile MOTU, the biggest manufacture of pro ESS gear and the maker of some of the best sounding sabre DACs, has only just released their first product with the ES9026!

    The 16a still sounds better than all this Chinese stuff.
     
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    Last edited: Apr 22, 2021
  14. GoldenOne

    GoldenOne Almost "Made"

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    It's been quite....interesting.
    His 180 u-turn on what has been his stance toward measuring products using only steady state tests/ideal conditions, to suddenly 'oh well its not real music so CLEARLY it doesn't count and wasn't fair', was surprising, and as expected a lot of people are a bit confused about that.

    Meanwhile on APS there has also been some information posted which might hint as to why Amir is so defensive of MQA. Obviously his ties to SMSL/Topping who have MQA in everything likely play a part, but also while at microsoft he was trying to push DRM schemes anyway.

    [​IMG]

    From @Josh83 :
    "To provide a little context for this, Zune and MS’s competitor to the iTunes Store used a DRM version of WMA designed by Amir. This was also part of Amir’s vision for MS’s video codecs, which caused him to be taken to task by Cory Doctorow, among others."

    Furthermore, Amir's company Madrona Digital, which its very unclear if it's even a real company or just a shell, received at least $180k in PPP and possibly over $300k

    https://opengovwa.com/labor-industries-contractor/MADROD*877JR
    https://projects.propublica.org/coronavirus/bailouts/loans/hometechusa-llc-6118618500
    Maybe more?: https://www.federalpay.org/paycheck-protection-program/hometechusa-llc-bellevue-wa

    This is despite their license to operate in WA being suspended in Aug 2019 and seemingly their employee list still showing employees that have not been there for years, with absurd job titles and overall very very vague information all round. (What the hell is a "journeyman technician"??)
     
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    Last edited: Apr 23, 2021
  15. GoldenOne

    GoldenOne Almost "Made"

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    Thought I should also post some additional info regarding MQA.
    Since the video has gone up I've had contact with a few manufacturers, who have MQA in their products, are actively not supporting MQA, or are in the process of adding MQA support.

    And a few interesting things have been said.

    Firstly, it seems that MQA MIGHT not actually have quite the level of intellectual property ownership that they appear to have. And the way they are operating may not be entirely legal.
    GPL is an interesting area. I'm looking into this further atm with the information i've been given but with how closed off MQA is it's hard to check for the necessary verification to this. So I want to make clear this is not proven.

    Secondly, Apparently, MQA is becoming very pushy about manufacturers keeping external processing/upsampling in the signal path at all times.
    This is a direct quote from a manufacturer to me recently:

    "Now, the MQA file, un-unfolded, is usually a 44.1kHz or 48kHz file, while unfolded it is played at the highest sample rate supported by the player that is a multiple of these rates (so e.g. 352.8 / 384kHz / 705.6 / 768kHz). There are few to no DACs out on the market that can handle a switch from e.g. 44.1kHz to 705.6kHz without an interruption to the sound, well, I should say I am not aware of any such DAC and certainly none of our company's devices have one, not even sure if it's theoretically possible. This is the reason for the interruptions to the sound many of our users are reporting when beginning to play an MQA track, seeking through it, skipping to another track, basically anything other than playing a whole MQA album in sequence.


    Now, MQA understandably do not want to want this to happen to their audio, so the recommendation to all of us, is to resample all incoming audio to their highest 44.1 / 48 multiple, regardless of whether it's MQA, in a manner consistent with MQA unfolding so that no break in the sound would occur.


    If we followed this recommendation, we would have to abandon the [name redacted for company anonymity] for bit perfect rendering of PCM audio at different sample rates."


    So not only does MQA want manufacturers to add upsampling before the DAC chip itself, they want manufacturers to use THEIR filter....

    This was also mentioned here by Doug Schneider: https://audiophilestyle.com/forums/topic/30381-mqa-is-vaporware/?do=findComment&comment=985782

    I am guessing this might be why ifi in newer products like the iDSD Neo is ONLY using the GTO filter. (which as shown is basically identical to the MQA renderer filter, if someone here has an iDSD neo and a half decent ADC it would be interesting to test. I can provide some standard and MQA-encoded whitenoise and impulse response files if needed)

    This means that with a product like that. You are effectively doing MQA rendering no matter what in order to prevent any interruption. Degrading performance of all standard PCM content just to keep MQA happy.....

    Some manufacturers have either been given strategic exceptions to this rule, such as those who's dacs are otherwise NOS. Or seemingly dCS, likely due to how their digital processing side is proprietary and likely more flexible than the average chip dac implementation and so they can avoid this issue.

    But one of the manufacturers expressed their frustration that they have been given an ultimatum of either NOT being allowed MQA support, or having to do the aforementioned 'upsample everything with MQA filter' approach.

    This is pretty damn concerning
     
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  16. Josh83

    Josh83 Friend

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    Just to clarify, this was actually me posting at AS, not @JoshMorr. I’m “JoshM” over there.
     
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  17. GoldenOne

    GoldenOne Almost "Made"

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    Ah apologies! Corrected the post
     
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  18. crenca

    crenca Friend

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    So about a dozen or so FTE at middle class income. I thought however that this company is real and does "high end" Revel/JBL home theatre installation up in Washington state? If so I am not sure what the relevance of this (essentially doxing) is. PPP was just stimulus for business...


    This would be cool. I am weary of iFi now (though I have older silver nano and iDac2 that I use mostly for travel) because of this issue. For now I can use older firmware to avoid GTO, but for how long, is it worth the effort, and what about the 93.298% of customers who will just put the latest firmware on because that's what your supposed to do right. @iFi audio , your on "the wrong side of history" as they say on this issue.

    This is one of the subtle ways MQA is forcing its ecosytem and has been known for a while, though the "average" consumer has neither the technical knowledge nor the attention span to understand it. Thanks for bringing it to the foreground again.
     
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  19. penguins

    penguins Friend, formerly known as fp627

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    This made me smile.

    Part of me has always wondered if Tidal was just a scheme to move money around or do some other gray area type business stuff one way or another under the guise of "legitimate business" by Jay Z and whoever else benefits from behind the scenes. Not just b/c of potential bad business practices as you mentioned but because too many things about it didn't seem to quite add up. Yes, it's better to keep this stuff under wraps normally, but in this case, I would imagine the publicity would actually help lend to an appearance of legitimacy.

    Similarly, once I realize ASR/Amir was a shill, I have also wondered the same thing. It would be a good cover for whatever he may or may not be doing with said Chinese or other audio mfgs and whatever else he does. Certainly much easier to bill for advertising services or "consulting costs", etc. (esp w/ regards to Chinese gov's capital control laws, the IRS, etc.) vs trying to move capital directly. I suspect the $300k is just icing on the cake in this scenario.
     
  20. Woland

    Woland Almost "Made"

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    They're not popular brands around here, but to be fair and accurate, many Topping DACs have no MQA support or have variants with no MQA support.

    Edit: a quick look at the SMSL website suggests they also don't have MQA in every DAC.
     
    Last edited: Apr 23, 2021

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