MQA is Vaporware

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9 hours ago, Fitzcaraldo215 said:

@Sal1950Agreed.  One of MQA's huge problems is that much of its "advantage" relies on psychoacoustics and the science of audible perception, of which Bob Stuart is one of the acknowledged world class masters.

 

 

Really?

 

Where are Stuart's papers and books that deal with original research in psychoacoustics and perception? MQA's premises are that ultrasonics matter and that temporal blur due to filtering at ultrasonic frequencies is a real issue. Yet, they support this by referring to papers that are more than a bit shaky (Oohashi, Kunchur, ...) and to their own papers in which they report in the vein of "Oh, we listened to this ourselves and yes it really matters. Believe us."

Where is the independent validation of this all?

 

If all of this were true, wouldn't it be so easy and so convincing to put a number of comparative  test files in the public domain, with accompanying listening instructions, that clearly and honestly  show what this is about?

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5 hours ago, Rt66indierock said:

 

 George Lydecker of Warner Music Group described the training process to convert files as lengthy. Several Warner employees spent a couple of months to learn the MQA conversion process in Cambridge.

 

Months for a technical training in mastering? To me that seems outrageous and, frankly, not to be believed. More like a finely-crafted message to make one believe that they (MQA) are doing something special.

 

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3 hours ago, Em2016 said:

 the whole folding of the region B (and region C, for completeness although there's not much happening in there) into region A to get a smaller file size looked clever to me.

 

Ironically, that was not even invented by MQA, but by the Japanese, quite a few years ago.

 

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14 hours ago, Fitzcaraldo215 said:

 

http://www.2l.no/hires/documentation/2L-MQA_Comparisons.pdf

 

They state that the MQA version folds recordings done at 352k down 3 times to 44k. That is considerably different from your version.

 

Your position is based on just that short statement, that a 352k recording is folded three times, in a blurb. That's all.

 

1) if you study the MQA patents, you'll find that there is no room for such 3 times folding.

 

2) if you study MQA's technical literature, as was made public since 2014 or so, you'll find that there is no 3 times folding. What you may find is an allowance to encode and decode a small portion of original signal above 48kHz, in other words, a little bit of a 192k recording (up to 56kHz or so). Not a 352/384k one.

 

3) if you understand how MQA works (which is not that hard at all), then you'll see that thruthful three times folding is not possible, unless the original signal has no content above, say, 48kHz.

 

4) there are a few post-MQA DAC spectral analyses on the web from files that are known to originate from 192k originals, which upon playback through an MQA DAC light the DAC's '192k' indicator. These spectra consistently show the result of lazy upsampling above 48kHz. No actual original content is conveyed.

In order for a recorded spectrum to show the fingerprint of this upsampling the signal has to contain a lot of treble. This can come from the music, but also from high-frequency interference (from CRTs and whatever) originally recorded with the music in the studio. In my experience 2L recordings do not contain much treble (at least the ones I tried), and were cleanly recorded so as not to be contaminated. That, and the typical modulation noise bump above 40kHz of many DAC chips and many ADC chips make these recordings hard to fingerprint. But again, AFAIK, all 192k recordings analysed so far show upsampling as the sole mechanism to get back to 192k upon MQA playback.

 

Of course you have the right to keep on dreaming.

 

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More analysis here http://www.pinkfishmedia.net/forum/showpost.php?p=3072610&postcount=619

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Fitz, it is clear that you don't even remotely understand how this works.

 

we have been aware of the precise difference between Core and Renderer from day one.

 

The Bluesound DAC does full decoding. The software does a first unfold, followed with upsampling. The result of that is sent to the DAC chip, whose oversampling is maximally suppressed (as this is now done in the SW). It is all very simple. If you stay clear of MQA Newspeak.

 

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Archimago has published the next stage in MQA deconstruction.

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9 hours ago, Fitzcaraldo215 said:

 only about the Dragonfly Black, which he says may not even have sufficient power to decode the MQA Core.

 

Not 'may'. It simply does not have the capabilities for doing a full decode. That is not a secret(*). Analysing now via a Dragonfly is interesting because it enables one to inject post-core synthetic test signals into a pure render stage. This is not possible with a Meridian Explorer 2 because it appears to contain a bug that prevents it from acting correctly on a core-decoded stream. This aside.

 

 

(* Even though some distributors, magazines, and commentators seem to have been, for a while, under the impression that this was a full MQA DAC. Look at the Beekhuyzen youtube channel for a train wreck.)

 

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9 hours ago, crenca said:

 

Thinking of the Chord vs MQA approach, is it fair to say that the "time domain smearing" IS the ringing, and that the lack of ringing in the MQA filters IS what they allege to be "time domain accuracy"?  I know this has already been described thus a 1000 times but just want to verify:  given this, then MQA trades aliasing for the lack of ringing - noise for ringing whereas the steep filter of the Chord Dave will have ringing but more accurate (i.e. little aliasing distortion) FR.

 

Ok, after all this I am still having a hard time tracking relevance in the audio band as I can't tell which approach as a paper tiger (a graph) is more relevant from 20-20.

...

Also, besides all this you have the question as to what exactly MQA is doing as an encoding process on the ADC side of things which is not addressed at all by your and archimago's work. 

 

Yes. The 'smear' is the 'ringing'. Ironically, from the sampling theorem and from other disciplines that rely on signal discretisation to extract information equivalent to timing accuracy in audio we know that the highest accuracy is reached with the steep filtering in place. It is the act of anti-alias filtering that allows one to convey the precise location in time of an impulse in a band-limited signal. Watts/Chord are correct in saying that their filter is timing accurate (to a degree orders beyond what is necessary for audio), whereas MQA's story is about apparent timing accuracy, purely for PR purposes.

 

As for the ADC: it is indeed almost impossible to asses what they are actually doing. There are many possibilities. For older recordings, like made on a PCM1630 or so, the MQA process could well correct its frequency domain magnitude and phase errors. This is valid, but then any mastering engineer with the knowledge could do so.

For low-rate recordings made with linear phase AA filters MQA could apply the weird all-pass filter they patented, something that imposes a large group delay onto the 18-22kHz band, thereby picking up the pre-ringing and dumping it down after the main impulse. This is rather freaky.

For high-rate recordings MQA simply subsamples with lazy/leaky AA filters. This is clearly stated in the patents and older technical documentation. Their justification is indeed that aliasing is subservient to temporal accuracy, and that with most music there is not enough ultrasonic content, and enough in-band noise, to make aliasing a non-issue.

 

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9 hours ago, Fitzcaraldo215 said:

I just found it difficult to understand how you got there.  I still do.

 

However, your statement does accuse Stuart and MQA of lying and fraud, because they have explicitly and consistently stated to the contrary many times.

 

Unfortunately, I do not find your version of it sufficiently well defined or documented to be able to simply understand your methodology, etc.  so as to be able to go along with you, not yet, at least.

 

It might even humble Stuart and MQA, and cause them very serious credibility issues, if not also lead to serious legal issues.

 

1) It is clear that you don't understand. Let me help you: this is entirely your problem, being either unwilling or not capable of understanding.

 

2) When the MQA ideas were published (end of 2014?) they were more or less clear. A bit later, when launching actual product, things got a bit less clear. Mostly thanks to the (as always) totally inept consumer audio press. In what followed MQA and Stuart have more and more chosen to navigate a path of (what is now clearly deliberate) obfuscation and newspeak. 'Folding' in their book has at least two different meanings. The first meaning is to take a 96k signal, split it into two bands, and fold the upper band in the data space below the lower band. This is a, give or take, non-destructive process and we all agree (and have verified)  that valid and true 96k content can be passed through a 48k channel this way, the origami trick. (As an aside, this method is not an MQA invention, there is Japanese prior art. Funny, actually.) 192k and higher signals are treated by laze subsampling and lazy upsampling. According to MQA the resultant aliasing and imaging is inconsequential. MQA's aim, their only aim, is to prevent steep low-pass filtering to happen anywhere. Their aim is not to pass on valid 192k or higher signal, only 'as-if 192k'. 'as-if' because it was never filtered down to 96k. They call this occasionally 'folding'. Incidentally, the phenomenon of aliasing and imaging is in the literature also sometimes called 'frequency folding'. This has nothing to do with the aforementioned origami folding. It is totally destructive.

 

 

3) Insufficiently documented??????? Did you actually read the body of work presented by Mans and others? Did you even try to understand?

 

4) Legal issues? This is consumer audio. Anything goes. No-one bothers. In the eyes of the real world out there audiophools are morons anyway.

 

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And let me add to 4)

 

Can you imagine a court case revolving around semantics in a niche hobby/consumer domain, a domain where no standard definitions exist for a great many processes and practices? Can you imagine how much fun such a case would be for a private-person plaintiff against a corporation that has spent a few years digging its IP trenches?

 

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5 minutes ago, esldude said:

 one MQA device selects one filter, and another selects differently and they don't all have the same capability upon playback

 

But of course it goes this way. MQA's aim is to optimise and authenticate up until the analogue signal at the output of the replay DAC. Since DACs analogue output filters differ, this implies that the digital input to the last stage of the DAC chips differ too. It makes sense.

 

This, of course, won't keep them from making a mess of it in actuality ;-)

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29 minutes ago, rickca said:

There is no assurance of getting the sound that the artist or recording engineer intended.  That's just marketing hype. 

 

Any such claim will always be marketing hype.

 

Unless one listens with the exact-same monitors, in a room with the exact-same acoustic, at the exact-same level, and with the exact-same amount of illegal substances imbibed.

 

And even then one cannot copy the artist's ears (luckily!) and state of mind.

 

 

 

Fidelity to what exactly?

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Miguelito, you have probably a setup error. There is no way thr core decoder in Tidal can output valid 176k.

 

to me the spectrum of your MQA capture looks like a 48k signal massacred by a badly configured sample rate convertor.

 

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On 28/06/2017 at 3:12 AM, miguelito said:

MQA unfolded to 24/96:

 

Still something not right?

 

Assuming they used the 96k original for the MQA release there really should not be that symmetry around 24kHz, which is telltale of  leaky upsampling from a 48kHz stream.

 

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https://beta.companieshouse.gov.uk/company/09123512/filing-history

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11 hours ago, Rt66indierock said:

This is type of software is only beginning. I seem to remember writing about wanting control of the filters a while back.

 

Not too long ago you could find threads here on CA about people fussing over the parameters for iZotope sample rate conversion, with tiny fractions of changes allegedly responsible for massive changes in sound. These threads were all the more funny because many of these people did not even understand what the parameters meant, and how illegal/invalid many of the filters they generated were. But blacks were blackerder, veils were lifted and then removed totally, the musicians were here and the listeners were there, over and over again, that much closer to the true sound.

 

 

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1 minute ago, esldude said:

Would you posit a guess as to how well that would go?

 

After two decades of attempting such education one tends to give up. At least in certain quarters.

 

 

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11 hours ago, Fitzcaraldo215 said:

If that is so clear and obvious, where is your lawsuit?  Or, how do you spell c-l-a-s-s a-c-t-i-o-n?

 

Thus spoke he who knows how much fun, how uplifting it is to wage a legal war against an entrenched company over something as frivole as consumer audio, with a subject matter that is, well, subjective, or at the best a case of ill-defined semantics.

 

Can you imagine this in front of a Texan judge and jury?

 

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And how would you go about verifying a 'drastically improved impulse response' without access to undoctored-with before and after files?

 

It would have been so easy for MQA to promote their process by putting up a website with short before and after clips. That is, if their invention amounted to anything at all...

 

As an aside, I once did public  listening test with a hires file, and two downsampled versions of it, one of which was filtered with maximum phase, i.e. lots of preringing. The listeners had to use quality equipment. The preference rankings were all over the place. Apparently preringing is not that detrimental to musical enjoyment as some would have us believe.

 

Keith Howard at Stereophile got the same result a couple of years ago. But this is quickly forgotten. The industry needs audible difference to sell. It does not matter that these differences are imagined. 

 

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46 minutes ago, PeterV said:

Well Fokus..let's ask MQA themselves, 

 

Didn't you notice that anything asked of MQA is handled with an expert lesson in obfuscation, handwaving, and newspeak?

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5 minutes ago, PeterV said:

The Nightfly' was released on TIDAL in MQA. Perfect material for me to audition and compare. But how much better is the impuls response ans time Smear of this record in MQA compared to the original (digital) master? Is this measurable or not?

 

The NF is an old digital recording, made at 1x rate and with analogue anti-aliasing filters. It may have ripple in the frequency domain. This could be redressed with inverse eq. It may have some aliasing in the top treble. This could be cut out with eq, at the cost of the top, of course. It sure has a lot of post ringing. This could only be removed with eq gradually filtering the treble. It has phase distortion. This could be corrected with an all pass filter. This would create pre ringing.

Nothing else can be done. There is no magic. None of this requires MQA.

 

But of course one could simply remaster the recording to make it sound nicer, and then slap on the letters MQA. This may sound better. But not thanks to MQA. There are plenty of tracks on Tidal that simply derive from better/different masters. This is sooooo obvious.

 

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That is not a review but a regurgitation of MQA promo material.

 

That a single apodising filter can undercut a chain of orthodox, half band filters and thus totally dominate the impulse response is common knowledge and is not even relevant in this story.

 

did I mention obfuscation?

 

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33 minutes ago, PeterV said:

. With MQA we are talking about the existence of unwanted time-smear in recordings due to (cumulative)  aliasing effects. 

 

The irony...

 

MQA claim that the ringing of ANTI aliasing filters is detrimental to sound quality. They tackle this by introducing aliasing effects in their masters. The opposite of what you stated.

 

 

Now for something objective. Ringing is clearly audible ... IF it happens at an audible frequency. For CD production the filter ringing is at 22kHz. Most adults really cannot hear this. For hires production the filter ringing at two or four times higher a frequency. Not even dogs are bothered.

 

MQA solves a non-problem. This would be perfectly fine, if only it were not a closed standard, excluding a large installed base of hardware and software, if it did not exclude existing DSP, and if it did not include a mechanism for DRM.

 

But this may be too objective for you?

 

 

 

 

 

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Beyonce's Lemonade is another example of a 1x MQA release. And then there is that one 2L recording that came off DAT.

 

The Beyonce is interesting in that even the normal release shows gradual filtering starting well below 20kHz, and there is a big hole from 20k upwards, iirc. Full MQA playback clearly shows the hardly filtered upsampling that is going on, almost like a NOS DAC.

 

This as an aside.