MQA is Vaporware

[esldude]

I think someone needs to create a digital cable that sounds DIGITAL.  Something with the crystalline clarity that makes a diamond envious.  The awe inspiring blackness of silence like looking into a black hole.  Total sharp edged super delineation with zero smear, no inherent softness, only the pure digital TRUTH.  Listening to music should be like jacking directly into the neocortex of the musician to experience the agony, ecstasy, the love, the loss, the happiness, the blues everything another person feels with ultimate digital directness. 

 

That is the cable I want someone to develop.

 

Then that cable would reveal MQA for what it is, and what it is not.

 

 

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2 hours ago, Sal1950 said:

I would love to see results of any human hearing tests that show people having positive response to ultrasonic frequencies. Most people don't hear anything much over 15k

You think that has anything to do with the size of the Organ of Corti being such that it really only works to about 15 or 16 khz?   The size being physically related to the sound frequency detected.  The size of the basilar membrane runs out of a place for the sound at 20khz if that.  I mean they gave a Nobel prize to the fellow who figured this out. 

 

So maybe he was wrong or maybe there are additional Nobels in the future of some boutique audio designers.  Maybe they'll win the first Nobel in medicine without even having a lab. 

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1 minute ago, The Computer Audiophile said:

What a great opportunity to help those who lacked the education to understand what they were doing. 

 

I'm guessing you offered some quick tips?

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

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MQA is really its evil twin AQM.  Authenticated Quality Missing.

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13 minutes ago, soxr said:

The problem with the hifi press is that they just copy paste the official versions, or do not understand them, which leads to video's like this, where the admit they were wrong:

 

 

Wow, that video is like a kernel that can unfold into all the ways MQA is a bad idea, how misinformation about it is presented and about half a dozen other angles.  I hardly know where to start.  Bottom line is MQA as it is being sold is nothing at all like what it serves out as a resulting music distribution format.  Fairy tales within fairy tales and still obscuring what it really does. 

 

The one that sticks out to me is on the one hand saying undecoded MQA sounds better because partial deblurring has occurred.  It sounds different when fully decoded.  And may sound better or worse depending upon the choices made by the engineer during MQA encoding.  This is the system that is supposed to fix errors and give us a transparent pipeline to exactly how things should sound and authenticate we are getting exactly what is intended?  Hans seems oblivious to the multiple contradictions in his presentation. 

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20 minutes ago, Fokus said:

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. 

 

 

It does get tiring and disgusting.  Everyone trusts their ears.  They seem to trust them most when you have shown them their ears are full of sh*te.  The slightest hint that someone somewhere under any circumstances hears something important and it is gospel.  Let them demonstrate they can hear no such thing, do so repeatedly, and it has no effect. 

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3 minutes ago, PeterV said:

I am not interested in measurements or graphs or reversed engineered software programs. All I care about is that MQA is contributing positively to the sound and that is just my personal observation. What I want to know is if this is due to the improvement in impuls response and as a result also to the reduction of time-smear in air. If my ears are capable to notice this en MQA claims are very clear about the reason and call this a 'paradigm shift' then all I care about is to get professional and objective confirmation. 

You have a few contradictions in your posting there.  You need to fix them or your post is non-sense.

 

All you care about is professional or objective confirmation.

 

You are not interested in measurements. 

 

Okay.  Good luck with that.

[esldude]

1 minute ago, Fokus said:

 

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

+1 million.

 

They have taken every possible opportunity to respond and side-stepped it with anything other than useful information.

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16 minutes ago, Fokus said:

 

No.

 

MQA's nemesis is the ringing visible before and after the main lobe in the impulse response of a linear phase filter.

 

They solve this by starting from a linear phase high sample rate recording, preferably 4x or higher, and then reduce this to 2x with an extremely leaky downsampling (anti-aliasing) filter, a filter with a very narrow impulse, but, obviously, with a lot of aliasing. They claim they analyse the source signal and then pick a downsampling filter so that the amount of aliasing that effectively hits the audible band does not exceed the natural noise already present in the audible band (i.o.w. the noise is to mask the aliasing). The 2x signal is then folded into 1x with the origami trick, for distribution (streaming, download, MQA-CD).

Upon replay the 1x signal is first unfolded to 2x (inverse origami), and then upsampled to the original rate with the leaky filters documented by Mansr here on CA. These filters obviously cause a lot of imaging, as can be seen here for a '192kHz' example:

 

 

 

====

 

As for the audibility of pre-ringing. You can follow Jud's advice. But even more telling would be this:

 

-reverse the file (i.e. front becomes back)

-convert with a minimum phase filter (see Jud's post)

-reverse the file again

 

Now you have a maximum phase file: all pre-ringing, no post-ringing. Have a listen.

 

 

 

 

Funny is it not.  The solution to ringing that is at an inaudible frequency is all this rigmarole which creates audible band aliasing which we can cover with noise masking, and feel completely okay about as being higher fidelity when played back with leaky imaging filters that might also intermodulate into the audible band. 

[esldude]

I haven't found any info saying the Nightfly was anything except digital all the way.  There were for various releases different masters.  Donald Fagen supposedly made aware of this decided on the master which was used on subsequent DVD stereo and multichannel releases.  Obviously we are all getting our info second, third or sixth hand.  I have never seen anything indicating analog tape was part of the process for any digital releases. I think people are confusing the 1 inch 45 IPS digital tapes with being analog.

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9 minutes ago, Rt66indierock said:

The one I was around and used only had analog outputs. I know the difference.

Which in no way automatically means analog tape was involved. 

With 32 tracks it sounds like they kept it digital till near the end.  Perhaps in some mixing on analog consoles it then had to see an ADC again.  None of that is enough to tell us analog tape was anywhere in the chain. 

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1 hour ago, Don Hills said:

OK. Tracked onto 32-track digital at 16/50.

Analogue out into an analogue desk for mixdown.

Output of the mixdown onto 4-track digital at 16/50.

Analogue out from that deck onto analogue tape at 15 or 30 ips for LP cutting, especially for copies to tape and LP plants around the world. 

Most likely from that analogue tape into an ADC at 16/44.1 for CD.

Just possibly analogue out from the digital deck into the ADC for CD.

 

So it's just possible that the original CDs might be one generation closer to the "definitive master" than the LPs, but unlikely. Most likely the analogue tape will be what we hear today. Does anyone have any hard info to indicate otherwise?

There are lists of people who worked on it, tales of what they used, and so and so forth.  No one mentioned analog tape. My thinking was 32 mixdown to 4 track digital which may have been done digital.  Some tales of how long the digital edits took and how frustrated the crew working on it became.  In those days you pick your edits and hit enter and wait a few hours. Maybe mastered from 4 track thru a mixing desk to 2 track.  May have gone thru an analog desk getting to 4 track.  So maybe as little as two more trips thru analog desks and two more ADCs and no tape in the chain anywhere.  But hey, just reading accounts by others here like all of us.

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1 hour ago, Rt66indierock said:

Take a look a picture of one. It had to be analog outputs. There weren't ways to make a record then without analog tape in 1982. 

I could care less what they made the cassettes and LP from.  I was only interested in CDs and other digital versions.

 

Do I remember rightly that Telarc used Soundstream's system to feed their mastered digital tapes to the cutter heads?  If so that could have also been done with Nightfly though I don't know how it was done.  I don't recall Telarc making an analog tape  master for their LPs and they were making those from digital recordings as early as 1978.

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5 minutes ago, Fokus said:

Given the scarcity of the 3Ms at that time, and the proliferation of competing formats, it stands to reason that for worldwide distribution the one compatible format was used, i.e. Analogue tape. For the first CD releases (plural, because this was presumably a world wide event) they could have used such analogue tape(s), but also, if they were lucky, one of the original 3M masters.

 

At any rate, all copying work was to be done in the analogue domain, as there were no digital interfaces nor sample rate converters. The only digital path existing was within the 3M system.

S-1610 adapter

So that users of the Sony PCM-1610 Digital Audio Processor could take advantage of Soundstream's editing system, the company developed the S-1610 Adapter. The adapter was a bidirectional two-channel format converter. Data from the Sony PCM-1610 were converted to the format used by the Soundstream DTR so that the data appearing at the input to the Digital Audio Interface looked to the DAI as if it had come from a DTR. Similarly, finished (edited) data in Soundstream format were restored to the Sony format by the adapter. Sony data were imported/exported at either of the two sample rates 44.1 kHz or 44.1/1.001 kHz.

 

The DAI is Digital Audio Interface which is where editing was done.  So it seems likely such an adapter would have been used when the CD version was released.  Again I don't know how it was done.  I see a paucity of data about analog tape being somewhere in the chain other than it was usually done that way at the time. Various versions of the Nightfly had the note: Digitally recorded, digitally mixed, and digitally mastered. 

 

I'll shut up now.  Makes no difference anyway.  The sound we can get from downloads or CDs is what it is regardless of how it got that way. 

[esldude]

Deleted. 

 

Maybe it went from the digital 3M to one of these 3M machines.

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10 hours ago, mansr said:

OK, let's take this recording apart. Again looking at track 2 from the Nightfly album, we begin by aligning the starts of the two version and look at the spectrogram of the left channel for the first 20 seconds, Tidal "hifi" on top and decoded MQA below:

The MQA version starts a full 8 seconds earlier, and there is a slight difference at 8-9 seconds. On closer inspection, The first second or so of the files match, then the CD is missing a chunk. Apparently the MQA process can restore content that has been edited out. Very impressive.

 

At the very end of the track, we find this:

The fadeout is clearly different. Less obvious is that here the MQA version is actually lagging by about 20 ms. In other words, it is slightly slower. It should be noted that this difference is far too small to be audible.

 

Now we trim the start and end, leaving only the part containing matching audio and align the beginning. Then for each second of audio, calculate the cross correlation between the two files and plot the lag corresponding to the maximum correlation:

It's a squiggly line. The lag with strongest correlation is increasingly negative which means the MQA file is falling behind. The overall linear nature is consistent with this being a different transfer from analogue using an ADC with a slightly faster clock. No normal digital workflow would introduce such a drift. To get a better look at the squiggles, we do a linear least squares fit and plot the residual:

This shows the relative time difference between the files for each second with compensation for the linear drift. The sudden jump at 182 seconds is a bit odd.

 

Regardless of the production details that have been debated here, it is clear that these two files come from different masters. Attributing differences in sound solely to MQA would be a big mistake.

Did not some early Sony gear run at 44,101 hz? Or am I mis-remembering that?  That would be near a 23 ppm speed difference which also would look like a minor clock speed difference.  That might explain your first graph though not the second.  If they were using an early Sony CD master for one of the versions, and that version was done on 44,101 hz sampling, while an MQA version ran at the proper though slightly slower speed of 44,100 hz. 

 

Its not clear without labels what your graph is showing.  Percent or milliseconds or sample slippage or what nor over what recording time you used.  So I don't know if that result fits the 23 ppm speed differences or not.

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1 hour ago, mansr said:

The average difference here is 92 ppm with the MQA version having more samples per seconds. How that came to be might be interesting, but whatever the explanation, it doesn't alter the fact that different masters are involved. The selling point of MQA (presented to consumers) is that of "de-blurring." Unless this process can magically restore 8 seconds of deleted audio, we're looking at something else entirely.

I suppose that highlights the question that doesn't get asked.

 

MQA=Master Quality Authenticated

 

Nobody asks "Which master?"

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13 minutes ago, Ralf11 said:

it's recursive - MQA is the Master

 

once DRM is propagated all over Skynet

Would have been more obvious is they named it MQAQM.

 

Master Quality Authenticated Quality Master

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1 hour ago, Charles Hansen said:

snip............
 

Three months later and (as usual) More Questions than Answers (MQA), as not one has been answered. Perhaps MQA is like the parakeet and just "resting".

 

Cheers,

Charles Hansen

I only wish it were so.  It could be just stunned.

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49 minutes ago, tobes said:

 

How much more can MQA throw away and still claim to be able to recover the sound of the original master?

I mean if the 24/44 MQA version of a 24/176 file is "Master Quality Authenticated" - how can a 16/44 MQA file be likewise?....or even better than a standard CD?

Future MQA upgrades will allow Scami-Origami-Multi-Euphonic-Multi-Dimensional-Folding.  This will allow a 4kbps stream to unfold without audible loss into a 768 khz/32 bit PCM or 44.8 mhz DSD playback condition.

 

MQA  SOME-MDF

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2 hours ago, darkmass said:

 

Could you show us your arithmetic on that?  Light in your dimension seems a wee bit slow.    

I have it at .65 inches at lightspeed for 55 picoseconds.  

 

186282 miles per second x 5280 ft per mile times 12 inches per foot =  11,802,827,520 inches per second.

 

Divide by 1 trillion and multiply by 55 and you get a bit over .65 inches per 55 picoseconds.

 

Alternatively 299,752,458 kilometers per second times 1000 for meters per second times 39.37 inches per meter divided by 1 trillion and multiplied by 55 results in about the same .65 inches per 55 picoseconds. 

[esldude]

1/(2pi x number of levels x sample rate)

 

Which works out to near 55 picoseconds for redbook.  This without dither as dither works like additional levels between zero and the LSB. 

[esldude]

9 minutes ago, mansr said:

Where did you get that formula? It doesn't agree with my derivation above.

I don't remember for certain.  I think I saw it mentioned first by JJ Johnston.  I also have seen it in a paper by Robert Stuart from the 1990's about the parameters of what was possible in digital recording.  It did seem to me the sample rate was incorrect and should have been Nyquist instead when I did the same derivation you have done. And also that it would be dependent upon the frequency of the signal.  Also that such derivations are for maximum signal levels.  And yes, the values are 65,536 in total, but go from zero to plus 32,768 and minus 32,767.  I did think you end up with 110 picoseconds instead of 220 because once the sample is above half the LSB it will get recorded as one LSB. 

[esldude]

For those wondering if it is for real on the temporal accuracy, I have used real gear and you can run a loopback test with 1 meter of cable and repeat with 2 meters of cable.  The difference in time along that cable is detectable at the proper level in a null test.  I was using 24 bits which effectively had noise levels at about 18 bits with the gear on hand.  One meter is about 3 nanoseconds depending upon the speed of propagation % of the particular cable involved.  

[esldude]

9 hours ago, jhwalker said:

 

According to my good friend Wikipedia

 

"the refractive index of air for visible light is about 1.0003, so the speed of light in air is about 299,700 kilometres (186,200 mi)"

 

So pretty much the same speed.

Does this mean Stuart will next come out with a special video UltraMEGAHiDef video format so the picture has the same blur in the image as caused by 10 meters of air?