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MQA is Vaporware


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9 minutes ago, Jim Austin said:

In other news, the leading producer of DAC chips will incorporate MQA natively into their DAC chips. That's big news, too, but that's been public for a while, so that's probably not it. 

 

Mobile  chips only for the time being, innit ? ;)

 

9 minutes ago, Jim Austin said:

The listening tests at McGill failed to establish a difference between MQA and PCM at the same rate.

 

Do we know if McGill tested for the uncommon bit depths that @Miska and @mansr's work unearthed ?

 

44 minutes ago, Jim Austin said:

It's apparent to me that you spent hundreds of hours reverse-engineering MQA in order to try to prove that it's invalid. 

 

I'd be a little bit more respectful of @mansr's knowledge, if I were you. But that's just me.

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On 5/18/2018 at 5:34 AM, adamdea said:

The odd thing about Jim Austin's sentence is that the frequency domain and the time domain are mathematically interchangeable. The Shannon's proof of the sampling theorem depends on this. That relationship is immutable. So how can they not be symmetrical and how can anything restore what can;t be lost?

 

Because music in the analog domain is not inherently band-limited. So, one has to apply an antialiasing filter pre-conversion, thus altering the signal that will be "perfectly" reconstructed (ignoring some complications related to amplitude quantization). 

 

It is in the assumption of bandwidth limitation that there is an implicit lack of symmetry. One counts errors in the frequency domain while ignoring errors introduced by antialiasing. In the generalized post-Shannon approach, those errors are counted--integrated into the theory. 

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On 5/18/2018 at 6:01 PM, mansr said:

The Shannon-Nyquist sampling theorem provides a sufficient condition for fixed-interval sampling to fully capture a signal and enable subsequent reconstruction. Later research has defined other conditions allowing certain signals to be accurately captured without fulfilling the Shannon-Nyquist criterion. A search for terms like sparse signal, sparse sampling, compressed sensing, and finite rate of innovation will turn up hundreds of papers spanning decades.

 

None of this is new. The reason it hasn't been applied to audio is that it is unnecessary. An audio signal has such a low bandwidth to begin with that the Shannon-Nyquist requirement is easily met. The data rates involved also pose no problems for processing, transmission, or storage systems. Even if some form of sparse sampling of audio could cut the data rate in half, say, there are good reasons not to do this outside very specific applications. Traditional sampling produces a signal that is easy to process in a multitude of ways (think of all the operations a DAW can do). That isn't necessarily true of sparse sampling. Why should we complicate everything only for the sake of a data rate reduction we don't need? I can't think of a single reason.

 

When, months ago, I started exploring this topic, I did the same Google searches you've apparently done. Yes, the most obvious application of non-Shannon sampling is when you've got a signal with high and low limits. But when you keep reading, you realize there's much more to it than that--but that it has not been applied much to signal processing. 

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3 hours ago, miguelito said:

This is key. I went to a demo in March 2015 and the MQA versions were quite better. But looking back and after all of the experience listening and comparing albums on TIDAL (MQA, TIDAL redbook, ripped redbook, and high res versions I own), it is pretty clear that the MQA gains in some albums are entirely due to remastering and not to MQA itself, and as such it could clearly be accomplished with PCM alone.

 

There certainly are plenty of MQA tracks/albums floating around whose CD-res versions are from different masters, but I have not found that to be the case for high-res versions; generally they appear to be from the same masters. To charge that using different masters in their demos is to suggest that they are engage in the worst sort of fraud. Even if you think them ethically challenged, it's illegal and extremely dangerous strategically. For that reason, I think it unlikely. 

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36 minutes ago, beetlemania said:

True that Ayre’s listen filter is similar to MQA’s filter. But I don’t recall that Ayre intended to engineer a closed system that all would have to adopt, from recording to user. Only one of your articles has addressed some of the downsides of MQA, and gently at that. I kindly suggest you interview some of the MQA critics for future articles. 

 

I have talked to several. Some do not want to go on the record. Others have signed noncompete agreements. Have you noticed that even on this forum most experts use pseudonyms? Doesn't make it impossible however, an it's a reasonable suggestion. 

38 minutes ago, beetlemania said:

Meanwhile, many of us have compared MQA to true hi-res and we’re not impressed. 

 

Fine--good. Thanks for listening with your ears. 

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9 minutes ago, mansr said:

The leading producers of DAC chips are ADI, AKM, Cirrus/Wolfson, and TI/BB. ESS is but a niche player.

 

Yeah, I wonder how a serious journalist like @Jim Austin could've made such an egregious mistake.

 

Ohwait...

 

"Milpitas, California - ESS Technology, the industry leader in audio and analog design, announced today that they will introduce versions of their SABRE®audio DACs that feature integrated MQA rendering. (...) "

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4 hours ago, miguelito said:

Just consider reading Bob's incomprehensible gibberish vs @mansr clear statements. Really, it is not that Bob is speaking at a more complex level. It is gibberish.

 

Do you think you can make a convincing case that this is true? It's a pretty serious accusation. Since some of this work has been published in scientific journals--I mean Bob Stuart's--you're accusing him of scientific misconduct, among other things. I'll point out again that his work has earned him distinction as a Fellow of the Audio Engineering Society. You are welcome to your opinion, but even without such distinction, there should be a high bar for that, IMO. 

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1 minute ago, Jim Austin said:

 

I have talked to several. Some do not want to go on the record. Others have signed noncompete agreements. Have you noticed that even on this forum most experts use pseudonyms? Doesn't make it impossible however, an it's a reasonable suggestion. 

 

Fine--good. Thanks for listening with your ears. 

Pseudonyms are used to protect privacy. Crazy people show up at places of business and call employers of people who’ve used real names. 

 

Pseudonyms are irrelevant when it comes to math. 2+2=4 for Jim Austin and BigBird. 

 

Mansr has frequently given his full name here on CA. Plus, I’m sure Bob has told you he has all the information about the MQA detractors (except archimago). Just ask Bob for some names and contact info b

Founder of Audiophile Style | My Audio Systems AudiophileStyleStickerWhite2.0.png AudiophileStyleStickerWhite7.1.4.png

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33 minutes ago, Mordikai said:

So you understand this stuff but Bruno Putzeys doesn't? Yawn, this is basically trolling at this point.

 

Hardly. Bruno has forgotten more about digital audio than I'll ever know, and as I've said before, I don't understand it either. The point is that as I've learned, it's not necessary for a digital engineer to understand this stuff. If it is what it claims to be, MQA is based on a rethinking of what digital audio engineers consider gospel. The question is whether it makes the music sound better. 

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3 minutes ago, Jim Austin said:

 

Do you think you can make a convincing case that this is true? It's a pretty serious accusation. Since some of this work has been published in scientific journals--I mean Bob Stuart's--you're accusing him of scientific misconduct, among other things. I'll point out again that his work has earned him distinction as a Fellow of the Audio Engineering Society. You are welcome to your opinion, but even without such distinction, there should be a high bar for that, IMO. 

The same AES who published Mayer & Moran and refused to publish articles showing the holes in the “research.”

 

Appealing to authority is a logical fallacy. 

Founder of Audiophile Style | My Audio Systems AudiophileStyleStickerWhite2.0.png AudiophileStyleStickerWhite7.1.4.png

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26 minutes ago, mansr said:

I did it to find out what was really going on. The officially available information seemed too good to be true. Turns out it was, as usual.

 

OK, I stand corrected. I don't know who you are, but you're clearly knowledgeable. I would not presume to label you as some sort of charlatan. 

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5 minutes ago, Jim Austin said:

 

Hardly. Bruno has forgotten more about digital audio than I'll ever know, and as I've said before, I don't understand it either. The point is that as I've learned, it's not necessary for a digital engineer to understand this stuff. If it is what it claims to be, MQA is based on a rethinking of what digital audio engineers consider gospel. The question is whether it makes the music sound better. 

 

Forgive me for being blunt but if you don't understand the technology why are you writing articles about it?

Sometimes it's like someone took a knife, baby
Edgy and dull and cut a six inch valley
Through the middle of my skull

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3 minutes ago, Jim Austin said:

 

OK, I stand corrected. I don't know who you are, but you're clearly knowledgeable. I would not presume to label you as some sort of charlatan. 

Here’s a video of Mans from 2012. The internet is full of more. 

 

P.S. You should read the threads on CA where he schools Gordon Rankin about how Arm chips work. Good stuff. 

 

 

Founder of Audiophile Style | My Audio Systems AudiophileStyleStickerWhite2.0.png AudiophileStyleStickerWhite7.1.4.png

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