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

[astromo]

A great read and a worthwhile addition to the knowledge base to inform the consumer and those who enjoy music.

 

Congratulations to @Archimago for all the hard work to draft the opening essay and to @The Computer Audiophile for engaging with the subject matter.

 

I thought it useful for my own interest to reflect back on Chris' initial listening impressions and views of MQA (with underlining by me for emphasis):

My First 24 Hours With MQA

 

Quote

Overall I am happy with the MQA music I’ve heard. I wish I could render an opinion, that would carry across all MQA products and music, that MQA is always better by a wide margin, but this isn’t the case. The differences I’ve heard so far are subtle and my opinions are limited to the music and hardware I used in the last 24 hours. I also have a suspicion that the MQA process will be more beneficial to recordings that were done under less than stellar circumstances (i.e. lesser quality A to D converters, etc…). The 2L recordings are done with the utmost care using very good equipment and very good engineers. While there is still improvements MQA has made to the original 2L masters, I’m willing to bet there are greater improvements to be made to more traditional popular recordings or very old recordings. On the other hand, it may not be easy to compare an MQA version and non-MQA version of some old recordings because the MQA version has been done with the white glove process. It would be the same as comparing two difference masters of the same album, of course they’ll sound different. There will be clear differences with or without MQA. The real question many people will want answered is, how much of the difference is MQA and how much is the white glove process? But, does this question really need to be answered? I’m not so sure because we don’t have the option of getting new white glove masters of some of our favorite music. If MQA is the impetus to get us better sounding music, that’s all that really matters. In a dream world we may have the option of a white glove MQA and white glove non-MQA, but this is the real world. The options are, MQA or live with what we already have. Anyway, the MQA train is finally leaving the building. I’m cautiously optimistic that everything will work out and we’ll have better sounding music without too much trouble.

 

That final line was telling. Prophecy or an possibly an underlying expectation that trouble would be unavoidable?

 

As with  @Archimago I'm very interested to read the findings of the McGill University work. I'd also be interested to understand the source of their research funding, so hopefully that is made clear at the time of publication.

 

Thanks for your effort and keep it going. There are many who appreciate the input from people who have access to the resources and technical capability that are simply beyond the average Joe.

[astromo]

6 hours ago, Archimago said:

 

"Lossless music registration"? Anyone use this kind of terminology? Is this even a "thing"?

 

Clearly this man has not explored or understood the issues with MQA. Furthermore he has not understood nor does he seem capable of showing that which he speaks of - whether in the "diminished transient response" or his belief in what kinds of "errors in the clock signal (that) cause jitter". He has talked about this as if with authority in the past.

 

All kinds of confusion and conflation to make comparisons that are inappropriate.

 

The crux of the argument for him is essentially this:

"So, like conventional PCM and DSD, MQA is not without losses but to my experience suffers from less loss than regular PCM and DSD, DSD being second best to my ears and over my equipment."

 

Yeah... Real scientific there. His ears. His equipment. How would he know there was "less loss"? I've never seen him give an example of what song or piece of music he's referring to to make such a comparison.

 

One obvious and gross error (along with a jab):

"The technical difference for techies without ears is that where in regular PCM - once digital - every bit remains intact, MQA uses a lossy compression for the signals above 48kHz."

 

Sorry Hans - pardon me if I think that the ears/brain of many of the tech folks including mine might be a tad more perceptive, if not at least younger with better frequency response. Major error there dude setting 48kHz as the boundary!

 

And how does he know that:

"The MQA circuits used in MQA DAC's does even sound better when non MQA sources are used."

 

What "MQA circuits" are you talking about? Again, clearly this man doesn't understand the system itself.

 

Fascinating that he lists a number of negatives about MQA in the latter part of the video, but just lets these issues pass... Seriously, it's not about the "angry mob who don't want to pay the license fee" that's a problem. It's the fact that MQA is not what he thinks it is and the fact that he says these erroneous things in support of folly that (at least personally) creates a sense of disgust ("mad" is not the correct emotional label when I listen to the claims such as the ones in this video these days).

 

So he wants audiophiles to spread the word about his channel at the end so he can keep people "informed". Apologies if I stay away from my PayPal account and Patreon as I have no desire to support misinformation.

 

@Archimago thank you for the "cut through". You saved me the effort of pointing out the flaws that I could spot in the HB presentation. Leaves me at this point with the thought of "bring on the McGill Uni study".

 

If the analytical work by Meyer and Moran are any guide:

Audibility of a CD-Standard A/DA/A Loop Inserted into High-Resolution Audio Playback

Quote

Claims both published and anecdotal are regularly made for audibly superior sound quality for two-channel audio encoded with longer word lengths and/or at higher sampling rates than the 16-bit/44.1-kHz CD standard. The authors report on a series of double-blind tests comparing the analog output of high-resolution players playing high-resolution recordings with the same signal passed through a 16-bit/44.1-kHz “bottleneck.” The tests were conducted for over a year using different systems and a variety of subjects. The systems included expensive professional monitors and one high-end system with electrostatic loudspeakers and expensive components and cables. The subjects included professional recording engineers, students in a university recording program, and dedicated audiophiles. The test results show that the CD-quality A/D/A loop was undetectable at normal-to-loud listening levels, by any of the subjects, on any of the playback systems. The noise of the CD-quality loop was audible only at very elevated levels.

we'll see confirmation of the ABX work you've reported on in your blog.

 

Interestingly, the Meyer Moran paper points to this commentary from another AES Journal Paper as part of the motivation for their study, dating back over ten years now:

Quote

As a licensor asserted in these pages [1],
A long-term audiophile criticism of the CD has been that it lacks the resolution to reproduce all the detail in a musical performance. ... High-quality audio practice now recognizes the CD channel as a "bottleneck" ... Higher resolution audio promises better sound than the CD, and the potential for this has already been demonstrated in carriers that permit a wider frequency response ... and greater dynamic range. ... [E]x-perience shows and anecdotal evidence suggests that higher sample rates "sound better." Typical observation are that with higher sampling rates the sound is clearer, smoother, has improved low-frequency definition, and is more "natural." In the author’s experience higher sample rates can lead to better fore-ground/background discrimination. "Objects" are better separated from the acoustic and therefore sound clearer and more "complete."

The similarity of language used to describe MQA by it's co-inventor with the description above is no coincidence (but it's certainly amusing to reflect upon). I've not fully read the paper that the above quote is extracted from yet but a quick skim made me notice this comment:

Quote

The author uses auditory modeling to illuminate the discussion in this paper, the background for which is fully
explained in [7] and [12].

 

From my own technical background, I know that modelling can only take you so far (George Box's advice is often quoted, "all models are wrong, some are useful" or something along those lines). Without empirical testing and validation, theory and models can quickly lead you down the garden path to leave you dancing around the magic mushrooms with the pixies and the fairies. To take Box's point, if you don't test your models empirically, it's not possible to understand the strengths and weaknesses and ultimately their reliability.

 

If MQA had been subjected to the rigour that Moran and Meyer applied (here's the testing detail from their paper that the abstract above alludes to):

Quote

With the help of about 60 members of the Boston Audio Society and many other interested parties, a series of double-blind (A/B/X) listening tests were held over a period of about a year. Many types of music and voice signals were included in the sources, from classical (choral, chamber, piano, orchestral) to jazz, pop, and rock music. The subjects included men and women of widely varying ages, acuities, and levels of musical and audio experience; many were audio professionals or serious students of the art.

 

Most of the tests were done using a pair of highly regarded, smooth-measuring full-range loudspeakers in a rural listening room with an ambient noise floor of about 19 dBA SPL, all electronics on (see Fig. 2). We also took the test setup to several other locations: a Boston-area mastering facility with very large four-way studio monitors; a local university audio facility, again with large high-powered monitors in a custom-designed listening space (the subjects for this test were students in the recording program); and a private high-end listening room equipped with well-reviewed electrostatic loudspeakers and very expensive electronics and cables. In all venues we performed informal tests of the subjects’ upper hearing limits to see
whether there was a correlation between this parameter and the audibility of differences.

We would already have an answer that would put all this angst and debate from the last couple of years beyond doubt to even the greatest proponents of the format.

 

Thanks again for your efforts.

[astromo]

3 hours ago, firedog said:

The Meyer Moran study has been fairly thoroughly discredited. Even one of the authors said he no longer stands by the conclusions. 

One of the big problems with the study was that they didn't find out the provenance of SACDs they used, and several of them were produced from upsampled Redbook. I wouldn't exactly call that testing "rigour". 

 

 So their study wasn't comparing hi-res recordings to Redbook at all in those cases, it was comparing Redbook source to Redbook source. And somehow they got to the conclusion that there was no discernable difference between Redbook and hi-res.

 

There were also some statistical issues with the study that put the findings in doubt. 

And as far as studies go, see this: http://www.aes.org/e-lib/browse.cfm?elib=18296

And that meta-analysis rejected the Meyer-Moran results for inclusion as being statistically suspect, i.e.,  results appearing to not be statistically random.

 

I'm not actually arguing the point of whether hi-res is audible - I'm just arguing that the Meyer - Moran study isn't where you should go if you want scientific proof it isn't. 

Thanks for pointing this out. Looks like I've got some reading to do.

 

From a quick squiz, this fella Josh Reiss has done a comprehensive piece of work. It provides an example for those pushing MQA to think about.

[astromo]

10 hours ago, sullis02 said:

 

Stuart has been flogging, and seeking ways to monetize, hi rez for two decades.   His "Coding Methods for High-Resolution Recording Systems," was presented at the 103rd AES Convention, New York, 1997, and by 2000 became the Meridian white paper "Coding High Quality Audio", which begat his March 2004 JAES paper "Coding for High-Resolution Audio Systems". ...the latter prompting skeptical comments  to JAES by Meyer, Moran, Roy Allison, and David Hardaway a few issues later.  Meyer and Moran's paper was a direct result of Stuart's ( at the time, virtually unsupported by published blind tests) claims.

 

There is lots of history here.  The AES for much of the past two decades was skeptical of the audible benefits of and 'need' for hi rez at the consumer playback end; but the 'political' tide in the organization  on that, seems to have changed in recent years.  There is likely a story there , too.  

 

 

 

Thanks for shedding light on the back story.

 

I raised the Moran and Meyer work a few posts back to contrast with the lack of transparency and empirical validation being offered by the proponents of MQA. It was pointed out that the M&M work was flawed.

 

I don't see that as a problem.

 

For me, that's still a positive. They published their method, theories and results and in time it was critiqued. To their credit, M&M appear to have acknowledged their shortcomings. Other researchers have gained benefit from those mistakes and it has added to the body of knowledge. That's good science.

 

I still consider that there is a stark contrast between good scientific method and the blurred assertions put forward to support the case for MQA.

 

It's very disappointing that Archimago's identity has been used to detract from the effort he has made. The listening test that he's pulled together deserves due credit, as does the technical analysis. It wipes the floor with the alternate empirical work put forward by the MQA proponents, which, from what I've seen, is meagre at best.

 

I look forward to a robust, evidence based refutation of Archimago's essay. If the previous comments in the negative are any guide, I'll be waiting a good while before I see much of value in that regard.

 

We'll see.

[astromo]

6 hours ago, Thuaveta said:

 

With respect, I generally trust the quality of the reporting in The Economist more than I trust Stereophile, as do I have more faith in The Economists' integrity and independence. Yet...

Thanks for that link.

 

I've always wondered why the Economist didn't run bylines. Now I know and the rationale and the approach has its place.

[astromo]

46 minutes ago, mcgillroy said:

 

Thus the solution to this dilemma offered by @John_Atkinson is to get the Economist to write an article about MQA. 

 

Let‘s all write friendly letters to Mr. Atkinson’s favorite British magazine and kindly ask to investigate the MQA-affair. With some luck it‘ll be out in July, right in sync with Mr. Atkinson’s deblurring article.

 

Gentleman, pls wet your quilts...

There's been limited coverage here:

https://www.1843magazine.com/technology/feel-the-noise

by one of their journos.

[astromo]

49 minutes ago, mcgillroy said:

 

Thus the solution to this dilemma offered by @John_Atkinson is to get the Economist to write an article about MQA. 

 

Let‘s all write friendly letters to Mr. Atkinson’s favorite British magazine and kindly ask to investigate the MQA-affair. With some luck it‘ll be out in July, right in sync with Mr. Atkinson’s deblurring article.

 

Gentleman, pls wet your quilts...

There's been limited coverage here:

https://www.1843magazine.com/technology/feel-the-noise

by one of their journos.

[astromo]

2 hours ago, Archimago said:

 

Again, it comes back to the speculation of what "deblurring" is. If "deblurring" is what makes an undecoded 24/44 or 24/48 MQA file "sound better" as they suggest, then there must be some processing being done during the encoding that affects those upper unencoded bits that they believe improves time-domain performance apart from the min phase/slow roll filter.

 

As I said yesterday about the "Daubert standard", until there is some actual science-based evidence about this, I refuse to believe "deblurring" (at least regarding the time-domain claim) is even a "thing" this scheme is able to improve/fix.

I really enjoyed reading about the "Daubert Standard". I'm not from the U.S., so it was news to me. Reads like very good legal sense.

 

Keep nailing the point of "deblurring" and the lack of scientific evidence to demonstrate that MQA is doing anything of value. It's always been a key issue for me.

[astromo]

3 hours ago, guymrob said:

I’ve a quote from KR March 2018 Stereophile that can probably sum up what most of us think:

 

“Today, I’m less enthusiastic about MQA than I was. High-resolution streaming and downloads are now readily available …. MQA requires the purchase of compatible equipment, and holds the potential to eventually control all signal processing, such as room EQ. I don’t see a need for it, therefore, and I hope it doesn’t force the elimination of high-resolution, non-MQA downloads.” — Kalman Rubinson. “Multichannel MQA”, Stereophile, March 2018

"Beep, beep, beep ..."

 

 - don't you love the sound of a reverse beeper?