Article: MQA: A Review of controversies, concerns, and cautions

[miguelito]

Thank you @Archimago. Great piece.

[miguelito]

5 hours ago, Chiger Yelam said:

It always worries me when I see rhetorical tricks being used to enhance an argument. I see no reason to mistrust the audiophile press on this issue as it is their job to give informed and unbiased reviews and there are clear attempts in this article to undermine trust in these reviews. Claiming that past or previous links to the industry in someway mean that they are incapable of doing their current jobs professionally strike me as a stretch. As to whether they "push" (author's quotes) MQA, well only in so much as they "push" any other product they give a good review to. Additionally just because the author has no industry affiliations does not make him/her somehow more trustworthy or unbiased; personally I trust someone more if they make their name and resume known rather than hiding behind anonymity.

If the author is entirely happy with the recent state of computer audio playback then fine, many of us are not and welcome innovative solutions which offer greater choice. This is my main objection to this article. If I want higher resolution sound and am sensible enough to ask my local HiFi retailer to audition new equipment (and can be trusted to make up my own mind) before I buy then what is the problem? The "internet blind test" put forward as evidence by our author is an insult to our intelligence.

I don't see MQA taking a monopoly position here, legacy codec will still be available and alternative improved products may emerge. If MQA and like minded innovators are undermined and ultimately fail then I fear we will be left with genuinely inferior products.

I am not sure what makes you think that the audiophile press has a true commitment to be true to the public and to unbiased reviews. Additionally, their opinions could be manipulated by what exactly is shown to them. I am not a conspiracy theorist, but I think you're being naive.

 

I listened to MQA in March 2015 (I honestly cannot remember the year... it was a long time ago) at Meridian in NYC. They played about 10 different tracks, both in purportedly "original" and MQA formats. The MQA tracks sounded remarkably better. But those were their choice tracks. The most stunning example was a 24/192 track that was then played in MQA format - I asked whether the MQA came from the same master or not, and I got some incomprehensible gibberish. 

 

After listening to a LOT of MQA over TIDAL (I have a dCS Rossini + Master Clock, which fully decodes MQA in hardware) I can tell you it is at best a mixed bag. I have found no instance in which the MQA file was markedly better than the high resolution version I own, in some cases it is a little different (eg Keith Jarrett's Köln Concert - I have a bunch of versions of this album).

 

I found @Archimago's article true to my experience listening to MQA as well as my read of the facts around it.

[miguelito]

2 hours ago, randyhat said:

Characterizations like "drinking the kool-aid" and referring to people you disagree with as being "brain washed" only serve to further polarize people around this issue rather than inform.

I don't think it is the most effective rhetorical instrument to use those words, but... Not every opinion is a valid opinion. The press has had some sort of bent in the last decade to allow for every argument to have the same weight - sometimes referred to bothsidesism. This is nonesense.

[miguelito]

6 hours ago, manisandher said:

You listened to the MQA version of KJ's Köln Concert on Tidal? I've never managed to find it.

 

https://tidal.com/album/77620365

 

I'll go further... I will give you my MQA review and comparison to the 24/96 version I own (from HDTracks)...

 

I find the MQA version to be slightly more "harmonically rich" meaning a bit more fullness to the notes. In fact I have found this in a few cases of solo piano recordings. The catch is I am not sure how true that extra richness is to the original recording. It feels like eq or the impact of the choice of the output filters. Additionally, the MQA version is louder.

 

There are many cases where the MQA versions don't sound any different (eg Morrissey's "Viva Hate") and cases where they sound worse than the better redbook masterings (eg INXS "Kick"). 

 

YMMV... 

[miguelito]

On 3/3/2018 at 1:55 PM, John_Atkinson said:

You omitted a fourth possibility: that the magazines' writers honesty report what they hear.

Possibly... But I have listened to a lot of MQA (see my signature for my system, and it is very carefully set up) and I can tell you some is good, some the same. It is not a panacea or anything of the sort espoused by the audiophile press. Come listen if you like, I live in Chelsea, NYC.

[miguelito]

12 hours ago, mansr said:

Mytek can disable MQA decoding entirely, which unlocks the usual set of filters. With MQA decoding enabled, even non-MQA content is processed with an MQA filter.

Ok that's pretty lame.

[miguelito]

3 minutes ago, ednaz said:

The brain sees things, not the eyes. Every one of those techniques is about changing how the brain perceives things. The same is true about sound - the ears capture but the brain hears. Hence psychoacoustics.

Very true. And we often are firstly drawn to over-sharpened, over saturated images - and one can similarly characterize this in sound. But all those artifacts get old because IMHO they don’t represent reality.

[miguelito]

6 hours ago, mansr said:

It's probably possible to sell old accounts to troll/shill farms.

If only MQA was a russian company...

[miguelito]

2 hours ago, wdw said:

I am concerned that we may just run John A. outta town if we continually post strong negatives about him and his magazine.  Consider that he is posting here and we should welcome his participation whereas R. Harley or any of his group of writers would never dare show up to debate any of these issues.  

Good point, thank you. I do appreciate that John Atkinson would show here and participate in the dialog. Some of us can get pretty rough at times, so hats off. I also appreciate that Stereophile has writers like Kalman Rubinson and Art Dudley who I have followed for a long while. 

[miguelito]

39 minutes ago, The Computer Audiophile said:

One other note about not engaging or not refuting data from an "anonymous" person, this is one of the first things Bob mentioned to me when he called. I'm not saying that Bob is setting JA's agenda or giving him talking points, but I just don't see why JA is sticking to that argument so hard. 

The scientific method is anonymous. There should be no truth value assigned to a statement by a "known authority", but rather if anyone including Bob Stuart disagrees with an analysis, they can come here and refute it with facts.

 

I read with great care Bob Stuart's articles including your Q&A here. I have found all of these quite devoid of details, and including no information that hasn't been assessed here. So I find the argument to "not engage with anonymous critiques" empty and in fact elitist. 

 

I just don't see how MQA can pull this stunt off.

[miguelito]

21 hours ago, John_Atkinson said:

 

With respect, yes, this is a core belief of mine, and has been since I worked in a research lab at the end of the 1960s. You have something relevant o say, hang it on the peg of your actual name. Just as I have done all my life - and even Doug Schneider has done! Until then, while I have read your article, and certainly have opinions on what you have written, I shall keep my thoughts to myself.

 

John Atkinson

Editor, Stereophile

Ok fine. The name is Stormy Daniels. Ok?

[miguelito]

On 3/8/2018 at 5:56 PM, mitchco said:

Wrt what is audible or not,  I would love to see more of this type of audibility testing in the consumer audio industry:

 

 

The best I could do is around 12 bits of resolution before auditory masking became too much.  The experiment posted is repeatable if anyone would like to try, plus files can be downloaded and listened to.

 

When Archimago and I attended the Vancouver Audio Show to listen to MQA files, we had an expectation that we would be presented with some AB testing, so we could hear the difference, as the system was certainly resolving enough :-) However, there were no comparisons and instead listened to some gobbledegook from the MQA sales rep, then a few nice sounding recordings, but no AB comparisons.

 

Given @Archimago's article, we now know why there are no audibility tests.

Actually, I DID get "A/B" played to me at Meridian in NYC around March of 2014 or so (maybe 2015).

 

The MQA versions were substantially better. As I've mentioned elsewhere, the most amazing case was a 24/192 recording and it's MQA version. However, after listening to a lot of MQA in the last couple of months, I realize it MUST have been an MQA version from a different mastering altogether. 

 

On top of it all, I got such gibberish answers to my questions that I was left with the impression of a poorly set up magic trick. Sad.

[miguelito]

53 minutes ago, mansr said:

Interpolation in general means calculating additional values between two given values. Applied to a sequence of samples, this naturally results in an integer multiple.

Also many possible kernels (base functions you use to create the interpolated shape - @mansr: obviously you know). I am not sure how sophisticated this gets in upsampling, but it can get pretty frigging crazy.

[miguelito]

2 hours ago, The Computer Audiophile said:

Who knew we’d hit 500 comments under an article about MQA :~)

It's like in the Young Frankenstein movie when someone says "Blucher"... 

[miguelito]

19 minutes ago, mitchco said:

As far as I know, currently today, this is the only way to achieve fully accurate sound reproduction where the frequency response is flat along with flat phase response and group delay to ones ears. Note this also corrects a loudspeakers timing response, as some 95% of loudspeakers are not time aligned. What would be the point of MQA deblurring if it can't deblur the loudspeaker? Makes no sense.

As you said... Consider what MQA does not account for:

1- DAC's analog stage

2- Pre/Amplifier

3- Speakers

4- Room

 

Moreover, given the design itself, and the restrictions to hardware rendering (ie upsampling with MQA-specified filters), MQA's design explicitly prevents you from applying DSP that would correct for the above.  All in the name of licensing revenues for MQA.

 

I do think people are entitled to get paid for their inventions. This however is a hostage situation sold on false pretenses in my opinion.

[miguelito]

I am still confused by the "temporal deblurring" feature touted around... My interpretation is that the use of the much softer rolloff upsampling filters results in much milder phase shifts at high frequencies, which means that a harmonic (that would have a bunch of frequencies) has the signal arriving in a narrower time interval than if some of the frequencies were phase shifted (phase shifts in the frequency domain are time offsets in the time domain). Is this what this is all about? And if so would this not be incredibly imperceptible?

 

 

@Archimago or @mansr - Can you comment on this? 

[miguelito]

One more thing: I would love to see a transfer function for MQA vs the original file, if at all possible. I suspect some of the sound differences are, basically, eq. Listening to Keith Jarrett's Koln Concert, I get the distinct impression that the MQA version has been eq'd compared to the original high res I have (24/96 from HDTracks).

[miguelito]

3 hours ago, Archimago said:

- Does it require impulse response data from all the ADCs, DSP processing used in the whole production chain, for each track that was affected, to work optimally? (ie. maybe it analyzes all the potential group delays and applies a "correction" filter to the track? One obvious issue with this is that in a multitrack recording, this also implies a need to remix.)

This MQA argument only makes sense in most cases where there is a mix of ADCs used or some tracks in the mix are purely digital like synthesizers, etc. 

 

Quote

- If there is no data about the equipment/process in the production chain, what does it do in a "batch" processing scenario? Important since it looks like the majority of the thousands of albums were not remixed and were not specially "authenticated"/supervised by the original artist/audio engineer.

Consider that about 8,000 albums have been encoded in MQA. Imagine there are 10 teams doing this encoding, and they manage to sort out all of the information of each album (ADCs etc) such that they can encode 1 album a day per team. And these teams work 252 days per year - ie every business day each team cranks out an album. This means that it will take 3.1 years for these teams to do these 8,000 albums. Ponder...

[miguelito]

8 minutes ago, mansr said:

That's 95% of all music, minimum.

Exactly. And I meant to say the MQA argument makes no sense.

[miguelito]

5 minutes ago, crenca said:

 

On the other hand, they are doing something - we all have heard it (i.e. the volume increase, the digitus or "instrument separation" depending on your take, etc.).  So perhaps it "works" to some extent even in a non-idealized situation of 95% of modern recordings:

 

https://www.computeraudiophile.com/forums/topic/38700-article-mqa-a-review-of-controversies-concerns-and-cautions/?page=24&tab=comments#comment-795567

 

at least, to some extent.  What that "something" is on the encoding side is the question.

Perhaps it works is not really an endorsement is it?

[miguelito]

6 hours ago, WiWavelength said:

"...the initial A/D conversion for nine out of every ten CDs is made with this Sony converter."

 

I have no reason to doubt this assertion. 

I wouldn't doubt that either. Using a better ADC, especially in those days, would no doubt render a better result. However, the MQA argument is "we know the ADC so we can fix the artifacts it added to the digital stream". But once you've encoded with a less than optimal ADC, you've lost information. Yes, you might improve it a bit with some processing, but there's no substitution for remastering. I would be very skeptical MQA is able to correct anything in the newest ADC technology.

[miguelito]

1 hour ago, firedog said:

They also claim they've analyzed so many tracks where they do know the ADC's used, that they've developed an algorithm that enables them to make a highly accurate guess about what ADC was used, even if provenance of the track isn't known. 

 

They can then apply the proper correction, and all of this is at least partially automated. 

How is this not the same as DSP at the end of the chain?

[miguelito]

36 minutes ago, firedog said:

How is it the same?

They are claiming to correct the timing errors of the ADC in the recording.DSP at the end of the chain has a different purpose.

Consider an ideal (maybe realistic for an analog recording):

1- mic--> analog mixing console --> ADC

2- PCM stream delivered as a file to you

3- Playback

 

And consider the process in MQA:

a- mic--> analog mixing console --> ADC

b- PCM --> deblurred PCM

c- MQA lossy compression

d- MQA file delivered to you

e- Playback over MQA decoder

 

Why can't I put step 'b' in step '3'? Are you saying that the lossy MQA compression is inextricable from 'b'? Why would that be? And if there's some processing done in 'c' that is part of 'b', why couldn't I still put it in '3'?

 

Explain. Please don't refer back to Bob Stuart BS (pun intended).

[miguelito]

8 hours ago, MikeyFresh said:

10 hours ago, Archimago said:

LOL - perhaps it's precisely because they attended The Shard that they didn't question some of the obvious!

 

Yes, precisely.

I think it is also fair to say that what is presented as "A/B" examples in such gatherings is suspect. When I listened to "A/B" comparisons at Meridian NYC there was no contest - the MQA version were markedly better. After a lot of listening on TIDAL (and full hardware decoding) I can't reproduce those differences. So my conclusion is they were showing cases where the files were not only MQA encoded but fully remastered.

[miguelito]

30 minutes ago, Fokus said:

Because the 'deblurring' requires an input at sample rate higher than 96kHz. Which is something you don't get your hands on at stage 3 under the new order.

Where did you get that from?? So you're saying that deblurring cannot be done on any recording done to redbook format such as Dire Straights's "Brothers in Arms"??? It is precisely in these early digital cases where it would make the most sense.

 

30 minutes ago, Fokus said:

As for any (real or imagined) corrections done to originals of 96kHz and lower: yes, all of these can be implemented anywhere in the flow. These are conceptually not different from any mastering step. For instance, if MQA have a magic plugin that makes any PCM1630 recording better, then they could sell that plugin to each and every mastering studio. Only ... MQA are not interested in this business model.

"Magic" is not in my vocabulary. Maybe you mean "eq"?