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Sun, 11/21/2010

Stereophile covers everything high-end and audiophile audio. Turntables and music servers, to solid-state and tube amplifiers and preamps, to loudspeakers.

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The Dealers' Open House is a section where dealers can post product news and announcements. We ask that dealers do not use this space as free advertising. The forum is not intended to support the buying or selling of goods or services, and those dealers looking to advertise their products or services should contact our publisher, Keith Pray, listed in the masthead of our magazine.

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The Manufacturers' Showcase is a section where manufacturers can post product news and announcements. We ask that manufacturers do not use this space as free advertising. The forum is not intended to support the buying or selling of goods or services, and those manufacturers looking to advertise their products should contact our publisher, Keith Pray, as listed in the masthead of our magazine.

Soundsmith's Peter Ledermann: Building, Mastering, and Giving Back

Six weeks ago, Jana Dagdagan and I visited the Peekskill, New York factory of Soundsmith—her first time there, my second. Although I didn't mention this to the company's President and Chief Engineer, Peter Ledermann, the thing that most impressed me during my second visit was how little had changed since my first, in April of 2015. In particular, all but two of the employees I saw at Soundsmith this year had been there during my first visit; that suggests an experienced workforce—no small advantage in the manufacturing of phono cartridges, where the requisite skills are specialized, to say the least—a setting where people feel sufficiently challenged and appreciated that they stick around for years rather than mere months.
Mon, 05/21/2018

Marc Mauillon: the Leçons of Lambert

Less than a minute into this rare realization of the Leçons de Ténèbres des Mercredi, Jeudi et Vendredi saints by Michel Lambert (ca 1610–1696), I knew I had to review it. Recorded for Harmonia Mundi in 24/88.2 hi-rez by Alban Moraud, who did a wonderful job capturing the resonant acoustic of La Courroie, Entraigues-sur-la-Sorgue, the 2-CD/51-track set showcases the extraordinarily agile, virtually vibrato-less and intentionally nasal bari-tenor of Marc Mauillon.
Sun, 05/20/2018

High-Fi?

"No one thing turned more people into audiophiles than the '60s counterculture," said Bruno, arm flung over his cash register. "It opened up the doors of sonic perception. Even the great audio designers of the day were countercultural mavericks!"

Bruno is the lanky, braided-beard, thirtysomething owner of a small, well-stocked record shop in Montreal, and we stood facing each other on either side of a glass case filled with vinyl paraphernalia. Bruno has made the most of his limited space. Every foot of each wall supports a shelf crammed with music-related merchandise: rock and jazz memorabilia, album covers, refurbished turntables. There's even a rack in the back for music and audio magazines, including Stereophile.

Fri, 05/18/2018

Recording of June 2018: After Bach

Brad Mehldau: After Bach
Brad Mehldau, piano
Nonesuch 7559-79318-0 (CD). 2018. Robert Hurwitz, exec. prod.; Tom Korkidis, prod. coord.; Tom Lazarus, eng., mix, mastering; Brad Montgomery, mix. ADD? TT: 69:24
Performance *****
Sonics *****

That American jazz pianist Brad Mehldau has made a recording of J.S. Bach's music should come as no great surprise to anyone who's followed his extraordinarily varied career. In many ways, it seems a natural progression.

Having become one of the most important jazz pianists of this century, and dabbled in classical-flavored music, film scores, and even performances of popular music (by Oasis Soundgarden and Nick Drake, to name just a few of the artists he's covered), Mehldau has finally gotten around to recording this album of five pieces by one of the greatest keyboard improvisers in history. Mehldau's method here is to play a more or less straight version of a Bach prelude or fugue from The Well-Tempered Clavier, BWV 846–893, followed by his own "After Bach" reimagining of the same piece.

Fri, 05/18/2018

MQA: Aliasing, B-Splines, Centers of Gravity On Karlheinz Brandenburg and MP3

Thu, 05/17/2018

COMMENTS
CG's picture

OK... Just how do you know that the "inaudible" aliasing is not the actual perceived benefit of such filters? The alias content is time synchronous with the program content and is hard to pinpoint when played back by itself. That does not mean that it doesn't have an audible effect.

Go find an amplifier or preamp using loop feedback that has marginal phase margin in the amplifier response. Under a variety of conditions into real loads (cables that are not terminated in their characteristic impedance, which they almost never are, as one example), these amplifiers will often produce low level intermodulation distortion products high in the audio band. These are obviously time synchronous with the program content. What's that sound like? An awful lot like the descriptions I've read of how MQA sounds.

As for "Aliasing cannot be a problem if there are no signals to alias.", well, duh! This is why band limiting filters are used in the original A-D conversion. If there are no signals above half the sampling rate, no "anti-alias" filter is required. (Random noise will alias, but that's at the, ahem, noise floor.)

But, it does beg the question of just why you'd need various folding and encoding schemes to allow for higher sample rates if there is no information there.

What's the point of 96 KHz sample rates if there is no audio information above, for example, 20 KHz?

In the mixed signal world outside of audio, higher sample rates are usually employed to make the filtering easier, mostly because passive filters take up space, cost money, and modern engineers don't like to design them!

I'm probably wrong here, but I thought the same reasoning was true in audio. Well performing filters are difficult to implement with analog components, so you move the sampling rate higher to relax the requirements for these filters. There *may* be little or no program material above that magical 20 KHz, but at least the practical filter implementation is more easily attained. If there are useful signals above 20 KHz, they're captured as a kind of bonus.

Again, I'm probably just showing my ignorance, but I fail to see how this is some "post-Shannon" sampling theory. At best, it's clever management of what signals appear where and at what levels. Psychoacoustics, not sampling theory.

MQA may sound exquisite for all I know. The explanations do not.

CG's picture

One other point...

B-spline and similar filter algorithms have been around for a while.

Wadia was perhaps the first audiophile oriented user of the concept. They were applying it to DACs back in the late 80's. Of the last century. Note that the Wadia products were developed about 35 years after Shannon, Hartley, and Nyquist were publishing papers about signal theory. We're now almost 35 years after Wadia...

https://www.stereophile.com/digitalprocessors/wadia_digital_1000_decodin...

http://www.gammaelectronics.xyz/s_1996-12_Wadia.html

http://www.hifi-advice.com/blog/specials/wadia-digital-company-special/w...

(In the last of these links, there's an article snippet about the ups and downs of Wadia as a corporation. If nothing else, always remember that a lot of audio companies are businesses with investors who expect a profitable return...)

Pioneer had something they called Legato Link that came soon thereafter. Several others followed. A search on Google on these subjects can quickly consume your morning.

Oh! One last thing.

If you look carefully at the Measurements sections of Stereophile reviews of DAC products, there's a couple plots that show distortion products for both harmonics as well as two tone IMD. Yet, you see all sorts of other products that seem to not be related. But, if you do the arithmetic (not complicated math) you quickly learn that these really are simple intermodulation distortion products caused by non-linearities most likely in the analog amplification portions of the DACs. You see, unless you have an analog low pass filter that cuts off just above the audio band, there's all sorts of imaging products that are the result of the digital to analog conversion process.

Here's some really nice pictorials of the process:

http://www.dspguide.com/ch3/3.htm

The takeaway to consider is that linearity outside the traditional audio band matters with digital to analog conversion. (Unless there's that analog filter right after the converter chip itself). If opamps or other amplification with loads of feedback are used, their linearity often deteriorates above the audio band due to the falling open loop gain. "Open loop" amplifiers also deteriorate as you go higher in frequency, but because the designers can't rely on feedback to correct for non-linearity, the amplifiers usually are linear over a wider frequency range. This doesn't mean that high feedback systems can't be made to work - you just have to plan and design accordingly. Keep in mind that the same argument holds for not only whatever amplifiers are in the DAC itself, but in whatever preamp and amplifiers you might be using in the chain as well.

leedom's picture

MQA: A Review of controversies, concerns, and cautions
https://www.computeraudiophile.com/ca/reviews/mqa-a-review-of-controvers...

jherbert's picture

...dann verwirre sie. German saying.

DH's picture

Record at very high sample rates 192K and above. Microphones basically don't pick up anything over 100k and certainly recordings can be made without info with extremely high frequencies.
Problem of band limiting, aliasing, etc eliminated. NO MQA needed.

dalethorn's picture

I read this through a few times, looked up the term equivocation in the dictionary, and thought: hmmmm....

B-splines and the like have a long history in noise reduction, so that part is understandable enough.

"If properly managed, upward imaging need have no negative impact on the sound, especially if the images are beyond the frequency range...." - OK, but is the 'If' always properly managed?

"....In the real world we do not have impulses in air." - hmmmm.

"Even this small error is with a highly unrealistic test signal. With actual music, ...." - hmmmm.

I wonder - even though we can't take possession of a proprietary MQA encoder to test on our own computers, it seems fair that we could get some people to sit down in a closed lab with such encoders to run some independent ad-hoc tests, which would likely reveal weaknesses in the MQA encoder(s). All complex software has bugs, and revealing those bugs - even some of them - would enable us to search more intelligently for specific failures in commercial music releases.

The problem here with MQA is that I'm not getting software to run on my computer on my own data, as when I'm using facebook or a Web browser, etc. In those cases, the public gets to know the bugs. With MQA, I'm getting only the canned output - the music - and the bug list is hidden from all of us.

spacehound's picture

Shannon's sampling theorEM (it's not a theorY as Jim falsely states) is PERFECT. No greater authority than Jim Austin himself just said so. Twice. Even if he did try to con us into this "theorY" nonsense.
And 'perfect' can't be improved on.

And time and frequency 'domains' are exactly the same thing, just looked at in two different ways. Just as saying "Cut this twenty inch stick so one of the two parts is twelve inches long" has the same result as saying "Cut this twenty inch stick so one of the two parts is eight inches long". It's that simple.

So just WHY does Stereophile keep pushing Stuart's/MQA's marketing BS?

dce22's picture

Jim Austin: Is MQA an application of post-Shannon sampling theory to audio coding?

Bob Stuart: Yes, very definitely, it is!

That is it people 2+2 no longer is 4 the king has spoken.

Bob Stuart: The specified level of aliasing is not audible, with a safe safety margin.

GTFO and take your distortion making machines with you.

Anton's picture

"Perfect" has been an ongoing digital code word, like, forever.

spacehound's picture

It's simple mathematics, cleverly figured out by Shannon. And it's as provably correct as Pythagoras' theorem. The only people who call it a theory are those who don't understand it or charlatans trying to sell us something.

Anton's picture

Remember “perfect sound forever?”

It was a lie.

So is MQA.

spacehound's picture

Sure, anyone who does basic tests on MQA quickly finds out its claims are false. Even the 'authentication', which is merely administrative, rarely happens in reality. And there is plenty of proof that the MQA people often 'authenticate' it anyway, even when the artists/producers point blank refuse to have anything to do with it. And a quick look with a 'scope and a spectrum analyser will prove the technical claims to be rubbish.

CDs? Hmmm. The original CDs were extremely good. They do last 'forever'. Well, up till now, at least :-). Philips, then one of Europe's largest corporations, truly believed in this format and placed strict quality controls on the few plants that made them, followed up with regular inspections.

Later, when they became 'mass market', made by all sorts of outfits worldwide, and sold in huge numbers, Philips could no longer control the quality so it gradually deteriorated.
Now, even in the average household room the later ones can corrode quite quickly due to poor application of the protective varnish (which is on the label side) and the now common direct label printing on that varnish, allowing the thin aluminium layer with the 'pits' to become partially unreadable, causing clicks, pops, and skips. And if that occurs on the index it won't play at all.

But 'Shannon' is totally solid. As I said earlier, it's a theorem, not a theory. If used as instructed (sample rate a minimum of twice the highest frequency you want to capture) it actually DOES result in perfect digital capture of all the possible analog waveforms. It's non-intuitive but it's true.
So if people will accept that adult humans simply CAN'T hear above about 20KHz then the 44.1K of CD is fine. Though if I had been 'in charge' I would have gone for 48K simply to eliminate all argument.

dalethorn's picture

I would add a very old saying: "A chain is only as strong as its weakest link". When you consider the number of processes in the recording and playback chain, and the number of hands (or 'bots) the music passes through before it gets to your ears, you'd want to have constant attention on all of that to maintain maximum purity of the data. My biggest (but not only) ongoing concern about MQA is that it appears to me they're trying to make it a truly robotic process so that every album can be 'processed' by automation, with a veneer of human interaction that's just vapor.

Maybe everyone is so used to automation that they aren't concerned about this aspect of it. I'm concerned about *every* aspect of automation that has a potential impact on the music.

In the past few weeks, I've come to the tentative conclusion that no matter how smart they make a filter (MQA), applying it robotically to every album is a bad idea. And I wonder how many people have thought this through, putting aside all of the other arguments for the moment.

Bogolu Haranath's picture

Hello everybody ........Why am I writing this comment on this forum about MQA? Read on ........ I have recently seen an "infomercial" about a new kind of microphone with a "triangular" shaped transducer diaphragm on Pro audio review journal. The company is called Ehrlund Microphones. If you are interested, check out their web site. They have a video posted on the web site how the microphones work. Essentially they say a triangular shaped diaphragm is superior compared to a round diaphragm which is commonly used because of superior "impulse response". They claim that the suboptimal impulse response causes distortion of the audio signal recorded. Again, check out their website for more detailed explanation. Now about MQA ....... Is "blurring", time domain errors caused by microphones? Is some how MQA correcting them as a "side benefit"? Probably JA is reading these comments along with Jim Austin. May be they could comment on this topic. JA is a recording engineer/producer. He may be interested in these triangular diaphragm microphones. May be in the near future somebody could work on triangular shaped loud speaker and head phone drivers as well.

Bogolu Haranath's picture

JVS ........ Great music recommendations. Bought most of them. Keep them coming. Thanks.

Jason Victor Serinus's picture

Not being a recording engineer, I have no comments on these microphones other than to say that words are words, measurements are measurements, and sonic results are more or less related to the same, but in ways that are not entirely predictable due to the limitations of measurements and the fact that, no matter how hard they pretend, human beings do not know everything.

spacehound's picture

Knowing they don't know everything is the very basis of all science. Science is a DISbelief system. Many laymen seem to have difficulty in understanding that.

Another problem is that perfect 'impulses' don't exist in reality so they can neither be measured nor heard.

And there's not much point in measuring imperfect impulses :-)

spacehound's picture

Nobody is listening.

Except for a tiny minority people are either against it or totally indifferent. And that's everywhere, it's not just Stereophile readers.

Is Stereophile too blind to see that?

ok's picture

..aliasing can't be audible since ultrasonic – but ultrasonic content should be audible despite being ultrasonic :-)

CG's picture

Very curious, isn't it? :8^)

spacehound's picture

It is the result of the recording process recording ALL the output of the instruments, audible or not, being recorded. and it's not a 'fault', it's an 'effect'.

Some instruments produce inaudible high frequencies which gets 'reflected' back into the audible range dues to the Shannon sample rate/frequency limitation, and is correctly termed an 'image' or 'imaging'.

Unfortunately MQA relies on weak' filters that don't prevent this imaging for the process to work at all. So on an MQA file this imaging can be heard quite clearly (again depending on the instruments) if you know what to listen for.

It tends to give a fake 'liveliness' to the music that would not have been on the original. Some people, including the Stereophile reviewers seem to like that, or pretend to.

dalethorn's picture

I'd like to build a list of tracks that have audible imaging like that.

Gumbo2000's picture

Stereophile might want to lay low on MQA for a while. Every new article makes MQA look more ridiculous.

Jason Victor Serinus's picture

Is the alternative to calling something "fake news" to now call it "too real news"? After all, what Jim did was to ask Bob Stuart a series of informed, highly technical questions, and then transcribe the answers.

Would the press make you happier if it did not ask questions, or only asked questions about issues that you are comfortable with? I pose these questions not to you in particular, but to everyone reading this.

The fact is, more companies are adding MQA decoding to their devices. That includes some mass market gear. Another batch of MQA CDs has been released in Asia. Major labels are onboard. The entire Warner catalog is going on Tidal in MQA. MQA is making its presence known.

To my mind, asking questions of the co-creator of MQA is essential. Note that there is no effort on Stereophile's part to control the responses to those answers, unless they cross the line to personal attack or downright irresponsible accusations. But everyone reading these comments knows that every time we discuss the acronym MQA, the naysayers will come out in force, posting again and again in hopes that if they say what they have to say enough times, people will ignore everything else and simply believe them. What we are doing is presenting the facts and sharing our experiences, and allowing people to read, listen, investigate, and then decide for themselves.

Gumbo2000's picture

more articles like the current one only continue to muddy the waters with BS (not referring to Bob). To paraphrase "With friends like Stereophile, who need enemies!"

spacehound's picture

The problem is believing the answers you get are true.

Stuart is quite clever. He is careful to not actually lie. He 'dissembles' instead. Some of his answers above are careful dissembling and some are mere gibberish.

Also.
What companies are doing is irrelevant. The buyer, and only the buyer, will decide. See '8 Track', 'DAT', etc.

Buyers are not going for Tidal, which remains 'microscopic' (though I use it myself, not because of MQA, but because of the '44.1' regular stuff).

And to date less than 0.02 percent of Tidal's catalogue is MQA. And it's decreasing, as far more new issue recordings are non-MQA than are MQA.

Warners and others just add MQA on afterwards. So the claimed 'authentication' can't happen. So what's MQA actually for?

Bogolu Haranath's picture

Thanks for responding to my comments .......... No, it is not about measurements ....... It is about "blurring " and about time domain errors caused by round diaphragm microphone "ringing" ....... This phenomenon may be similar to what MQA is supposed to be correcting ....... Since most microphones are made with round diaphragm, which are being used for at least 100 years or more, the so called "blurring" may be a distortion caused by microphones themselves and not entirely digital artifact ........I am not an engineer either ......... As I mentioned, if you visit the Ehrlund microphone web site and watch the video, you will know what I am talking about ......... The video is appox. 30 minutes long ........ Thanks again ..........

T-NYC's picture

... may equal Post - Stereophile. Enough PR BS. Stuart may need the money although his retirement should be secure via Meridian; notably Peter Craven is never part of these infomercials. Please, get back to reviewing magic cables & racks -- at least these do not debase the source material. And for an informed, impartial look at MQA try Archimago's Musings -- he's not selling anything -- not MQA licenses nor advertising.

dalethorn's picture

Archimaga is not selling anything? I dispute that. After all, the head of that site paid for his "article".

T-NYC's picture

Your comment is disingenuous. What does it have to do with his multiple objective reports containing lots of hard experimental data, both measurements and controlled listening tests, by himself and others? I mentioned his site purely because his articles are very well done, and link to many others doing similar experiments and thus are a much faster way to find many sources of hard data than Google. I suggest you read them and then ask him how much he earns from the site. My guess is not enough to pay for test gear; that this is truly an informed enthusiast's passion, unlike Stereophile which stopped being a thought-leader in the 1990s and has primarily served an industry PR function since. I'm okay with that except when it becomes ridiculously blatant as it has with MQA.

dalethorn's picture

Disingenuous you say? No - I challenged your assertion that "he isn't selling anything". Whether he's merely making a living and his employer is the actual seller makes no difference to the issue.

Archimaga had his chance to publish a clean article, but instead packed it with lots of personal angst. Now he can go back and clean all of that up and make it suitable for AES or IEEE or whatever, but the intent was and is clear from the beginning.

And besides, nobody I know is going to take the time to validate any of those "proofs". What we want to know is what effect is has on the sound, and is it likely to become a DRM tool. And as I posted elsewhere on this forum, it would be great if Bob and friends would organize a test event so many of us could test his encoder for bugs. We would NOT need access to any code or algorithms or other secrets - just the computers under Bob's watchful eye so that we can take a non-MQA file to the MQA coded state and see what the possibilities are.

T-NYC's picture

I am going to take your concerns at face value because you are not selling anything ;-0 You need to read his MQA thread and follow the links to others; not one article but roughly twenty. A pain because blogs show them in reverse order. You will find ample evidence that sound is affected. "Bob and his friends" are trying to sell this. If you read my AES post above you'll see -- no controlled listening tests THREE YEARS after the announcement. This is a scam, and if it were just more magic cable type nonsense it wouldn't matter because we can make choices about what we buy. MQA affects the source material. The record companies are enthused because MQA (like DSD) has a theme-song: "Buy It Again, Sam". However, this time around Lo-Fi is built in through a compressive algorithm of very limited application value, originally intended only to improve streaming sound and now being applied to CDs. Why would you compress a CD, adding artifacts?. Money, that's why!

dalethorn's picture

"You need to read his MQA thread..."

Erm, no, because it comes from a source that's not only unprofessional, but has unethical behaviors.

T-NYC's picture

he's a degreed EE and what is unethical about him?

dalethorn's picture

The source, boss, the source...

The CA guy, his "biggest" anti-MQA threads in the Whole World, and the unethical behavior that's been described at length here in previous months' topics.

I'm sure you can easily find what you need.

Archimago's picture

Re: Dale's comment.

1. I have no ties to the industry. My employer services the public and my day job is not audio related though my background training does allow me to say a few things related to this topic matter.

2. The "proofs" were reviewed by 3 others who have backgrounds in audio engineering and computer science.

3. Please... I don't think my writing was all that "packed with personal angst". I expressed what I thought needed to be said based on facts, reasonable opinions and I hope logical conclusions. I think the audiophile public can appreciate my perspective in the service of consumer freedoms amongst the sea of uncritical support from the audio magazines as if this were some kind of true "revolution" rather than an attempt at control, using techniques which actually decreased potential fidelity of playback. If the press actually addressed these issues directly and fostered debate, I would not need to say anything, would I?

dalethorn's picture

The problem here is not your facts. I've seen the charts and graphs and don't dispute them. How they are interpreted could be a problem, and if I remember correctly, your famous article added a lot of interpretation.

Archimago's picture

What's the point of charts and graphs if not for providing insights into the meanings, interpretations and explaining implications?

Whether one agrees with the interpretations I leave to the readers. But if one disagrees then by all means discuss the concerns rather than vague insinuations and insults.

dalethorn's picture

Your interpretations disagree wildly with others who've published articles here, which leads me to think that you'd get more respect for your articles if you could build some info-bridges to the customers here who might read those articles. I don't find them useful, albeit I am a tech person. [Flame deleted by John Atkinson]

Archimago's picture

Dale, the "info-bridge" has always been there. While there are elements to the purely subjective philosophy that I do not agree with, I can appreciate the opinions of those who hold on to that stance even if I disagree. No need to get angry.

The issue with MQA has to do mainly with the product itself and the way it's promoted. Just because it exists doesn't mean it's any good.

Flames are unnecessary Dale.

dalethorn's picture

Info-bridge means getting around the fact that your opinions disagree wildly with what I see published here. Anger and emotions have nothing to do with your disagreements, it's about the facts only.

Archimago's picture

Yeah I got a few buck for writing the article. It was the standard amount Chris gives for headline articles.

I don't think I need to divulge the exact amount just like I don't think anyone here should need to divulge how much they get for their writing.

I can however tell you that I make about 4x the amount per day at my day job. It took many hours to research that piece and time to double check with others 'in the know'.

No sir, money is NOT my motivation.

dalethorn's picture

Your motivation was never in question. Your interpretations of the graphic data can be questioned, not so much your motivation. The biggest problem is where the call for that article came from, and their motivation was made crystal clear as anti-MQA, end of sentence.

Personally, I see a lot of credibility on the pro-MQA side, and some - even if not an equal amount - on the anti-MQA side. My impression is that you're fighting a losing battle, and a big factor in that losing effort is alienating good people who also have serious reservations about it.

Archimago's picture

We'll see ultimately which side of history the debate settles on in the not too distant future I think.

I got a PM about writing an article to summarize concerns raised by a very long thread. Many have been critical of MQA for months if not years. I got a small amount of money for the review article. So what?

argyle_mikey's picture

How about a poll ?
Choices :
a). A monthly MQA article
b). A regular monthly review of a “budget” component (in the last year you’ve reviewed just 7).

Mike

jimtavegia's picture

better is better, but I could only hear the music starting at about 1:19 or the 1:20 point. As someone who does much recording and owns over 16 microphones, some with only 5db of self noise, I work very hard at the venue to listen for room noises and artifacts than can ruin my efforts.

It still seems to me that MQA is more about master control, but if it does ultimately sound better then the market will decide. The problem here is that if most of the major labels subscribe then WE don't get to choose other than buying a MQA capable DAC or not. I am not sure if this is the same as a DSD recording session mixed down for rebook sale. All of my SACD releases do have a rebook layer so I don't need an SACD player unless I want to hear the most. The price of entry into SACD player land is not cheap anymore and certainly not as cheap as gaining entry to hear MQA files. There is still much to be sorted here.

Ortofan's picture

... the Pioneer Elite BDP-80FD DVD unit will play SACD discs and costs about $300. Otherwise there are SACD capable audio players available from Marantz, Yamaha and Denon for about $1200.

adamdea's picture

I think Jim deserves some praise for putting to Bob Stuart some points which others have raised for some time.
I don’t know why Bob eschewed the opportunity to respond to Archimagos article but this filled in some of the gaps.
I have criticised Jim for not asking probing questions in the past, and so it’s only fair to give credit for getting Bob Stuart to address some of the issues. One might I suppose go as far as to draw an analogy with the Frost Nixon interview where, in advance Frost was seen by many as being too soft and lightweight.

In many ways I see Bob’s Stuart’s answers as a remarkable mix of evasion and white flag. Is that lack of pressing follow up questions a weakness or a strength? Perhaps Bob would only go on the record if he had confidence that his responses would be received uncritically.

Well, anyway I thought it was useful. Is it safe to assume that we now know what time smear is? Is it uncharitable to point out that this could not possibly justify the hype? Or that it is somewhat difficult to accept that this could be what Bob meant all along? Or to point out that if quantisation is the issue then cutting 16/44 to noise shaped 13 bit seems an odd sort of progress?

T-NYC's picture

https://www.researchgate.net/post/Is_Nyquist_Shannon_sampling_theorem_no...

Note: compressive sampling based on prediction NOT high-fidelity; very useful for mobile phone and similar where intelligible results not complete data reconstruction (AKA fidelity) is the goal.

T-NYC's picture

At AES 2017, Bob Stuart was asked if there had been any scientific listening tests performed on MQA. The question was from Bruno Putzeys, mathematical physicist & accomplished audio designer. The answer three years after the launch of MQA was no. The room got very quiet.

dalethorn's picture

A far better test (as I noted elsewhere) than merely listening to whatever "output" Bob would lay on the testers' desks would be to allow the testers to apply the codec to PCM files themselves (in Bob's lab of course), then listen to the before and after right there.

Bob would retain all secrets, and the testers would not only be able to validate the before and after results, they'd be able to try different things (within whatever are the allowable encoding parameters) to see what bugs might be hiding in the encoding software.

Archimago's picture

Controlled pre and post-MQA processing is what the supposedly upcoming study from McGill University is addressing. That will be interesting (if the results surface).

I don't think it's about bugs. Rather the differences we can already find on analysis of the decoded signal is by design and clearly are the results of a lossy process necessary for data reduction and the upsampled reconstruction.

dalethorn's picture

It's about bugs at some level if the industry becomes less demanding of quality, which is likely. Bad enough to have bad intent (if that's the case) in applying potential DRM, but it's even worse if further corruption creeps in due to bugs.

T-NYC's picture

DT, there is no interest in this (your proposition) at Meridian / MQA. It's been three years (see my post above). This is merde served fresh. BTW, again note Dr Peter Craven long ago disassociated himself from MQA. He has not been publicly involved since AES 2014. Ever wonder why? I do not know of a single physicist nor cognition-researcher who's work is with high-fidelity audio or touches on it who buys into this; quite the opposite.

dalethorn's picture

As Bob Stuart comes from audio and Peter Craven from math, is there something I should look for to tell me why Craven should be involved in MQA beyond the tech aspect of the code? I do recall that there were problems with early MQA releases and noise levels that was fixed, and many albums were remastered to accomodate that fix. I imagine Craven would have been involved in that. So I wonder - has Craven disassociated himself from MQA to the extent that if the codes need more work, he will not do any of that work?

Bogolu Haranath's picture

Since you wrote on this forum that you own many microphones and do many recordings, you may be interested about Ehrlund microphones. The transducer diaphragm in these microphones is "triangular" in shape. Probably the microphones you use have round diaphragm, which is very common. The company claims that their new type of microphone has superior "impulse response" and is better suited for recording. If you are not already aware of it, check out their website. They have a appox. 30 minute video posted on their website which explains the concept in more detail. Again, the name is Ehrlund microphones.

jimtavegia's picture

I am sure that due to high quality engineering that these new mics will sound good, acceptable, but I am concerned that the pistonic action with equal pressure being the driving force behind circular diaphragm designs. Until I had heard and used one I would pass no judgement other than it not being tried or used by other established companies, but that was a choice by their engineers and does in any way alter the performance of a new choice in design. The automobile industry has often had to result in differing speaker driver shapes due to space limitation and most often sound excellent.

I will try and find a dealer for an audition as changes and improvements are always welcome in trying to capture more in a recording event. Thanks.

Bogolu Haranath's picture

Hello ...... Me again ........ There is a new album by artist Morgan Agren, "Through the eyes of a Morgchestra" which I think is recorded using Ehrlund microphones ........ Check it out if you want to ......... I think it came out recently in 2017 .......... I did not explore all the new recordings by all the artists using these microphones (yet) ...................

jimtavegia's picture

The MP3 format will not allow much of a test. Is there a CD version for sale that you know?

Bogolu Haranath's picture

Thanks for responding to my comments ........ I don't know whether the recording is available in CD or not. You can check the Hi-Res download websites and streaming websites like Tidal ......... I downloaded it from iTunes ........ Well ...... It sounds good even with 256Kbs resolution ..........

dalethorn's picture

The artist says that the album you reference was created with a MIDI, but will be performed later by a symphony orchestra. So how can a person relate the quality of the microphones if there is no real acoustic sound?

Bogolu Haranath's picture

I don't know all the details of the recording ...... From what I understand the drums were recorded using Ehrlund "triangular" diaphragm mics ........ The artist Morgan Agren is a drummer .......... He has a video posted on You Tube and Google search .............

dalethorn's picture

I have a drum recording by 'Tutt-Keltner' that has a variety of high quality drum sounds suitable for evaluating the mics used for the recording. Listening to the album you've referenced, I don't get enough sense of drum "skins" in real space that I could make a judgement with. It just sounds electronic to me, unless you have a specific track from that album in mind that reveals acoustic drum sounds very clearly.

Bogolu Haranath's picture

You probably have lot more experience listening to music and drum sounds and various mics, than I do ...... There are several tracks I can hear drums ........ I can't recommend just one or a few tracks with good drum sound ......... You may wanna check the artist's website and videos and decide for yourself ...... I got this recommendation from a friend ..........

dalethorn's picture

I played quite a few tracks from the various Morgan Agren albums, but didn't hear anything I thought unusual.

On the other hand, Stereophile has (or had) a test CD that has Gordon Holt reading text into a dozen different pro mics, and the differences in their sound has to be heard - fascinating stuff.

Bogolu Haranath's picture

There is another album by the same artist released couple of years earlier ....... It is called "Batterie Deluxe" ....... It has drum sounds .......... I don't know whether it was recorded with the new mics ......... You may wanna check that one too .........

Bogolu Haranath's picture

Yes .... I do have that CD which I got many years ago ........... Sadly JGH is not around ......... So, we don't know how he sounds with these new microphones .......... If you can find any other albums of any other artists using these new mics, let us know .......... I sure will be interested .........

Bogolu Haranath's picture

This type of triangular diaphragm transducer would be great for headphones too .......... The diaphragm is supposed to cover very wide band width ......... This type of diaphragm could also be used for a single driver loudspeakers .......... Imagine that .........

Bogolu Haranath's picture

Till those types of headphones and loudspeakers are available, we may not be able to fully appreciate the full potential of these new types of microphones ............ I am all excited about the future of audio reproduction ............

dalethorn's picture

I've reviewed several hundred headphones, and published EQ curves (i.e. the inverse of a response curve) for most of those. Headphone response (ignoring in-ear types) varies pretty radically between the different models, and that's assuming a perfect fit with no issues.

While the advantages of better drivers (for example, the Focal Utopia) can be heard through the choppy frequency responses, the sonic differences in drivers are a very small factor compared to the ragged responses.

Note that this is not mere perception - if you check Innerfidelity's measured curves, you can even see large response differences between different samples of the same headphone! With speakers, you have much more flexibility in adjusting the speakers, the listening position, and the room treatments (including drapes, curtains, etc.)

Bogolu Haranath's picture

The ragged and choppy frequency response you mentioned is the ringing, I think ........... The round diaphragm may be the reason for this ........ Most of the headphone measurements show this kind of response usually from 1 KHz going up .......... For most of the loudspeakers the crossover is in this region between midrange and tweeter .......... Some of the harshness, smearing etc. audiophiles talk about happens in this region .......... some people attribute this to metallic tweeters ......... Also, some people blame this to digital recording .......... A square diaphragm shows less of this ringing phenomenon than a round diaphragm .......A triangular diaphragm shows even less of this ringing phenomenon than a square diaphragm .......... You can see all this being demonstrated in several videos on Ehrlund website ........ Some of the people listening to MQA, reported that they hear "smoothness" to the sound in this crossover region ........ Probably the MQA DSP is donig this .........Ehrlund website does not talk about MQA of course ...........

Bogolu Haranath's picture

This ringing probably is coming from the center of the round diaphragm, because round diaphragm starts "beaming" like a flash light as the frequency goes up ............ Round diaphragm has a wider area of sound dispersion and coverage at the periphery than the center portion ........ You probably already know all about this sound dispersion phenomenon ..........

dalethorn's picture

Take a look at this Stereophile article on a single-driver speaker. Note especially the reviewer's listening comments on page 2, for example: "The conclusion I eventually reached was that the tension I felt with speakers other than the ClairAudient 2+2 arose from subtle distortions caused by the crossovers and dissimilar drivers."

https://www.stereophile.com/content/audience-clairaudient-22-loudspeaker...

https://www.stereophile.com/content/audience-clairaudient-22-loudspeaker...

Bogolu Haranath's picture

I read that review a while back ...... The jagged and choppy response you mentioned is probably coming from the ringing ........... As you can see in the headphone measurements this kind of jagged response is higher in frequency say from 1 KHz and up .......... This is usually the crossover region between the midrange and tweeter .......... The ear is very sensitive in this region ........ This jagged frequency response does not happen with a triangular diaphragm, as shown on those videos .........

Bogolu Haranath's picture

One of the comments I made somehow disappeared from this forum ( I did not use any profanities) ........ Anyway .......... The comment is about ringing of the round diaphragm versus a square diaphragm versus a triangular diaphragm .......... The triangular diaphragm shows the least amount of ringing ......... All this information is available on Ehrlund microphones website ...........

dalethorn's picture

There's enough confusion here to make some things disappear, and part of that is because we're kinda off-topic with the microphone stuff. I am going to look closer at the Ehrlund microphone site to see how they're progressing.

dalethorn's picture

OK - taking a long look at the Ehrlund mic reviews, some by people I know like the Tapeop and Gearslutz guys, the overall impressions are an excellent mic, comparable to the best, with the most obvious differences from perceived neutrality being the emphasized top end and possibly a slight shyness in the lower treble/presence region. Based on what I know about current mastering and some of the high-end headphone tunings like the Focal series or AudioQuest models use, the Ehrlund looks like a great mic for piano, organ, percussion etc.

One reviewer noted his difficulties with trying to record acoustic guitar with the Ehrlund, and apparently gave up. But another reviewer noted similar difficulties and how he fixed the problem, so perhaps the Ehrlund can work well with acoustic guitars if the right pickup is used. In any case, I was looking for specific gotchas, and didn't find any fatal weaknesses from those reviews.

Bogolu Haranath's picture

Thanks for your response ......... I was trying to connect all the dots ........ We all know that the two weakest links in the audio chain are the microphone at one end and the headphone/loudspeaker at the other end .......... What if ultra low distortion diaphragms are used for both? ......... Won't that be great for audio recording and reproduction .......... Think about it ..........

Bogolu Haranath's picture

Agreed ....... I own Focal Utopias which I purchased about a year ago ........ I very much enjoy listening to them ........ I also own Audeze Lcd -4, Lcd-x and recently acquired Lcd-Mx-4 .......... I also own AQ Night owls .......... Lcd-4 is the best in bass reproduction ........... Others are also good in various other ways especially in easy drivability ........ I am a frequent visitor to Innerfidelity website ......... None of the headphones available today have "flat" frequency response from 20Hz to 20 KHz ........ For that matter none of the loudspeakers available today have "flat" frequency response from 20 Hz to 20 KHz ......... These new microphone "triangular" diaphragm transducer is supposed to have "flat" frequency response from below 20 Hz to well above 20 KHz ........... That is why I am excited, if and when some company(s) come up with the "triangular" or some other different shaped transducer(s) for the headphones and loudspeakers we may not experience the full potential of audio recording and reproduction ........ To paraphrase the great JGH, "down with the round", may be not down with "flat" ........

Bogolu Haranath's picture

I forgot to mention ........... I also own a pair of Westone W-60 in-ear universal fit model .......... I am working on a custom fit model ............

Bogolu Haranath's picture

When the ultra low distortion transducers become available, we can always use external EQ and DSP to suit personal listening tastes and preferences ......... It is like putting icing on a great cake ........ The cake has be great to begin with .........

Bogolu Haranath's picture

Think about it ........ "Perfect sound forever" is possible in the very near future ......... If you can believe it ..........

mrkaic's picture

Is this MQA algorithm published anywhere? I'd like to see the equations and analyze it myself.

dalethorn's picture

It's more closely guarded than the schematic for the NASA warp drive.

Indydan's picture

You're confusing NASA with Star Trek...

Bogolu Haranath's picture

It is proprietary DSP I think ........ They have patents for it .........

Bogolu Haranath's picture

Do we need a "special counsel" appointed to investigate this? .......... Is there some kind of "collusion" between the audio press and MQA? .............

Pages

MQA: Aliasing, B-Splines, Centers of Gravity Improved MQA Encoding

Thu, 05/17/2018

COMMENTS
CG's picture

OK... Just how do you know that the "inaudible" aliasing is not the actual perceived benefit of such filters? The alias content is time synchronous with the program content and is hard to pinpoint when played back by itself. That does not mean that it doesn't have an audible effect.

Go find an amplifier or preamp using loop feedback that has marginal phase margin in the amplifier response. Under a variety of conditions into real loads (cables that are not terminated in their characteristic impedance, which they almost never are, as one example), these amplifiers will often produce low level intermodulation distortion products high in the audio band. These are obviously time synchronous with the program content. What's that sound like? An awful lot like the descriptions I've read of how MQA sounds.

As for "Aliasing cannot be a problem if there are no signals to alias.", well, duh! This is why band limiting filters are used in the original A-D conversion. If there are no signals above half the sampling rate, no "anti-alias" filter is required. (Random noise will alias, but that's at the, ahem, noise floor.)

But, it does beg the question of just why you'd need various folding and encoding schemes to allow for higher sample rates if there is no information there.

What's the point of 96 KHz sample rates if there is no audio information above, for example, 20 KHz?

In the mixed signal world outside of audio, higher sample rates are usually employed to make the filtering easier, mostly because passive filters take up space, cost money, and modern engineers don't like to design them!

I'm probably wrong here, but I thought the same reasoning was true in audio. Well performing filters are difficult to implement with analog components, so you move the sampling rate higher to relax the requirements for these filters. There *may* be little or no program material above that magical 20 KHz, but at least the practical filter implementation is more easily attained. If there are useful signals above 20 KHz, they're captured as a kind of bonus.

Again, I'm probably just showing my ignorance, but I fail to see how this is some "post-Shannon" sampling theory. At best, it's clever management of what signals appear where and at what levels. Psychoacoustics, not sampling theory.

MQA may sound exquisite for all I know. The explanations do not.

CG's picture

One other point...

B-spline and similar filter algorithms have been around for a while.

Wadia was perhaps the first audiophile oriented user of the concept. They were applying it to DACs back in the late 80's. Of the last century. Note that the Wadia products were developed about 35 years after Shannon, Hartley, and Nyquist were publishing papers about signal theory. We're now almost 35 years after Wadia...

https://www.stereophile.com/digitalprocessors/wadia_digital_1000_decodin...

http://www.gammaelectronics.xyz/s_1996-12_Wadia.html

http://www.hifi-advice.com/blog/specials/wadia-digital-company-special/w...

(In the last of these links, there's an article snippet about the ups and downs of Wadia as a corporation. If nothing else, always remember that a lot of audio companies are businesses with investors who expect a profitable return...)

Pioneer had something they called Legato Link that came soon thereafter. Several others followed. A search on Google on these subjects can quickly consume your morning.

Oh! One last thing.

If you look carefully at the Measurements sections of Stereophile reviews of DAC products, there's a couple plots that show distortion products for both harmonics as well as two tone IMD. Yet, you see all sorts of other products that seem to not be related. But, if you do the arithmetic (not complicated math) you quickly learn that these really are simple intermodulation distortion products caused by non-linearities most likely in the analog amplification portions of the DACs. You see, unless you have an analog low pass filter that cuts off just above the audio band, there's all sorts of imaging products that are the result of the digital to analog conversion process.

Here's some really nice pictorials of the process:

http://www.dspguide.com/ch3/3.htm

The takeaway to consider is that linearity outside the traditional audio band matters with digital to analog conversion. (Unless there's that analog filter right after the converter chip itself). If opamps or other amplification with loads of feedback are used, their linearity often deteriorates above the audio band due to the falling open loop gain. "Open loop" amplifiers also deteriorate as you go higher in frequency, but because the designers can't rely on feedback to correct for non-linearity, the amplifiers usually are linear over a wider frequency range. This doesn't mean that high feedback systems can't be made to work - you just have to plan and design accordingly. Keep in mind that the same argument holds for not only whatever amplifiers are in the DAC itself, but in whatever preamp and amplifiers you might be using in the chain as well.

leedom's picture

MQA: A Review of controversies, concerns, and cautions
https://www.computeraudiophile.com/ca/reviews/mqa-a-review-of-controvers...

jherbert's picture

...dann verwirre sie. German saying.

DH's picture

Record at very high sample rates 192K and above. Microphones basically don't pick up anything over 100k and certainly recordings can be made without info with extremely high frequencies.
Problem of band limiting, aliasing, etc eliminated. NO MQA needed.

dalethorn's picture

I read this through a few times, looked up the term equivocation in the dictionary, and thought: hmmmm....

B-splines and the like have a long history in noise reduction, so that part is understandable enough.

"If properly managed, upward imaging need have no negative impact on the sound, especially if the images are beyond the frequency range...." - OK, but is the 'If' always properly managed?

"....In the real world we do not have impulses in air." - hmmmm.

"Even this small error is with a highly unrealistic test signal. With actual music, ...." - hmmmm.

I wonder - even though we can't take possession of a proprietary MQA encoder to test on our own computers, it seems fair that we could get some people to sit down in a closed lab with such encoders to run some independent ad-hoc tests, which would likely reveal weaknesses in the MQA encoder(s). All complex software has bugs, and revealing those bugs - even some of them - would enable us to search more intelligently for specific failures in commercial music releases.

The problem here with MQA is that I'm not getting software to run on my computer on my own data, as when I'm using facebook or a Web browser, etc. In those cases, the public gets to know the bugs. With MQA, I'm getting only the canned output - the music - and the bug list is hidden from all of us.

spacehound's picture

Shannon's sampling theorEM (it's not a theorY as Jim falsely states) is PERFECT. No greater authority than Jim Austin himself just said so. Twice. Even if he did try to con us into this "theorY" nonsense.
And 'perfect' can't be improved on.

And time and frequency 'domains' are exactly the same thing, just looked at in two different ways. Just as saying "Cut this twenty inch stick so one of the two parts is twelve inches long" has the same result as saying "Cut this twenty inch stick so one of the two parts is eight inches long". It's that simple.

So just WHY does Stereophile keep pushing Stuart's/MQA's marketing BS?

dce22's picture

Jim Austin: Is MQA an application of post-Shannon sampling theory to audio coding?

Bob Stuart: Yes, very definitely, it is!

That is it people 2+2 no longer is 4 the king has spoken.

Bob Stuart: The specified level of aliasing is not audible, with a safe safety margin.

GTFO and take your distortion making machines with you.

Anton's picture

"Perfect" has been an ongoing digital code word, like, forever.

spacehound's picture

It's simple mathematics, cleverly figured out by Shannon. And it's as provably correct as Pythagoras' theorem. The only people who call it a theory are those who don't understand it or charlatans trying to sell us something.

Anton's picture

Remember “perfect sound forever?”

It was a lie.

So is MQA.

spacehound's picture

Sure, anyone who does basic tests on MQA quickly finds out its claims are false. Even the 'authentication', which is merely administrative, rarely happens in reality. And there is plenty of proof that the MQA people often 'authenticate' it anyway, even when the artists/producers point blank refuse to have anything to do with it. And a quick look with a 'scope and a spectrum analyser will prove the technical claims to be rubbish.

CDs? Hmmm. The original CDs were extremely good. They do last 'forever'. Well, up till now, at least :-). Philips, then one of Europe's largest corporations, truly believed in this format and placed strict quality controls on the few plants that made them, followed up with regular inspections.

Later, when they became 'mass market', made by all sorts of outfits worldwide, and sold in huge numbers, Philips could no longer control the quality so it gradually deteriorated.
Now, even in the average household room the later ones can corrode quite quickly due to poor application of the protective varnish (which is on the label side) and the now common direct label printing on that varnish, allowing the thin aluminium layer with the 'pits' to become partially unreadable, causing clicks, pops, and skips. And if that occurs on the index it won't play at all.

But 'Shannon' is totally solid. As I said earlier, it's a theorem, not a theory. If used as instructed (sample rate a minimum of twice the highest frequency you want to capture) it actually DOES result in perfect digital capture of all the possible analog waveforms. It's non-intuitive but it's true.
So if people will accept that adult humans simply CAN'T hear above about 20KHz then the 44.1K of CD is fine. Though if I had been 'in charge' I would have gone for 48K simply to eliminate all argument.

dalethorn's picture

I would add a very old saying: "A chain is only as strong as its weakest link". When you consider the number of processes in the recording and playback chain, and the number of hands (or 'bots) the music passes through before it gets to your ears, you'd want to have constant attention on all of that to maintain maximum purity of the data. My biggest (but not only) ongoing concern about MQA is that it appears to me they're trying to make it a truly robotic process so that every album can be 'processed' by automation, with a veneer of human interaction that's just vapor.

Maybe everyone is so used to automation that they aren't concerned about this aspect of it. I'm concerned about *every* aspect of automation that has a potential impact on the music.

In the past few weeks, I've come to the tentative conclusion that no matter how smart they make a filter (MQA), applying it robotically to every album is a bad idea. And I wonder how many people have thought this through, putting aside all of the other arguments for the moment.

Bogolu Haranath's picture

Hello everybody ........Why am I writing this comment on this forum about MQA? Read on ........ I have recently seen an "infomercial" about a new kind of microphone with a "triangular" shaped transducer diaphragm on Pro audio review journal. The company is called Ehrlund Microphones. If you are interested, check out their web site. They have a video posted on the web site how the microphones work. Essentially they say a triangular shaped diaphragm is superior compared to a round diaphragm which is commonly used because of superior "impulse response". They claim that the suboptimal impulse response causes distortion of the audio signal recorded. Again, check out their website for more detailed explanation. Now about MQA ....... Is "blurring", time domain errors caused by microphones? Is some how MQA correcting them as a "side benefit"? Probably JA is reading these comments along with Jim Austin. May be they could comment on this topic. JA is a recording engineer/producer. He may be interested in these triangular diaphragm microphones. May be in the near future somebody could work on triangular shaped loud speaker and head phone drivers as well.

Bogolu Haranath's picture

JVS ........ Great music recommendations. Bought most of them. Keep them coming. Thanks.

Jason Victor Serinus's picture

Not being a recording engineer, I have no comments on these microphones other than to say that words are words, measurements are measurements, and sonic results are more or less related to the same, but in ways that are not entirely predictable due to the limitations of measurements and the fact that, no matter how hard they pretend, human beings do not know everything.

spacehound's picture

Knowing they don't know everything is the very basis of all science. Science is a DISbelief system. Many laymen seem to have difficulty in understanding that.

Another problem is that perfect 'impulses' don't exist in reality so they can neither be measured nor heard.

And there's not much point in measuring imperfect impulses :-)

spacehound's picture

Nobody is listening.

Except for a tiny minority people are either against it or totally indifferent. And that's everywhere, it's not just Stereophile readers.

Is Stereophile too blind to see that?

ok's picture

..aliasing can't be audible since ultrasonic – but ultrasonic content should be audible despite being ultrasonic :-)

CG's picture

Very curious, isn't it? :8^)

spacehound's picture

It is the result of the recording process recording ALL the output of the instruments, audible or not, being recorded. and it's not a 'fault', it's an 'effect'.

Some instruments produce inaudible high frequencies which gets 'reflected' back into the audible range dues to the Shannon sample rate/frequency limitation, and is correctly termed an 'image' or 'imaging'.

Unfortunately MQA relies on weak' filters that don't prevent this imaging for the process to work at all. So on an MQA file this imaging can be heard quite clearly (again depending on the instruments) if you know what to listen for.

It tends to give a fake 'liveliness' to the music that would not have been on the original. Some people, including the Stereophile reviewers seem to like that, or pretend to.

dalethorn's picture

I'd like to build a list of tracks that have audible imaging like that.

Gumbo2000's picture

Stereophile might want to lay low on MQA for a while. Every new article makes MQA look more ridiculous.

Jason Victor Serinus's picture

Is the alternative to calling something "fake news" to now call it "too real news"? After all, what Jim did was to ask Bob Stuart a series of informed, highly technical questions, and then transcribe the answers.

Would the press make you happier if it did not ask questions, or only asked questions about issues that you are comfortable with? I pose these questions not to you in particular, but to everyone reading this.

The fact is, more companies are adding MQA decoding to their devices. That includes some mass market gear. Another batch of MQA CDs has been released in Asia. Major labels are onboard. The entire Warner catalog is going on Tidal in MQA. MQA is making its presence known.

To my mind, asking questions of the co-creator of MQA is essential. Note that there is no effort on Stereophile's part to control the responses to those answers, unless they cross the line to personal attack or downright irresponsible accusations. But everyone reading these comments knows that every time we discuss the acronym MQA, the naysayers will come out in force, posting again and again in hopes that if they say what they have to say enough times, people will ignore everything else and simply believe them. What we are doing is presenting the facts and sharing our experiences, and allowing people to read, listen, investigate, and then decide for themselves.

Gumbo2000's picture

more articles like the current one only continue to muddy the waters with BS (not referring to Bob). To paraphrase "With friends like Stereophile, who need enemies!"

spacehound's picture

The problem is believing the answers you get are true.

Stuart is quite clever. He is careful to not actually lie. He 'dissembles' instead. Some of his answers above are careful dissembling and some are mere gibberish.

Also.
What companies are doing is irrelevant. The buyer, and only the buyer, will decide. See '8 Track', 'DAT', etc.

Buyers are not going for Tidal, which remains 'microscopic' (though I use it myself, not because of MQA, but because of the '44.1' regular stuff).

And to date less than 0.02 percent of Tidal's catalogue is MQA. And it's decreasing, as far more new issue recordings are non-MQA than are MQA.

Warners and others just add MQA on afterwards. So the claimed 'authentication' can't happen. So what's MQA actually for?

Bogolu Haranath's picture

Thanks for responding to my comments .......... No, it is not about measurements ....... It is about "blurring " and about time domain errors caused by round diaphragm microphone "ringing" ....... This phenomenon may be similar to what MQA is supposed to be correcting ....... Since most microphones are made with round diaphragm, which are being used for at least 100 years or more, the so called "blurring" may be a distortion caused by microphones themselves and not entirely digital artifact ........I am not an engineer either ......... As I mentioned, if you visit the Ehrlund microphone web site and watch the video, you will know what I am talking about ......... The video is appox. 30 minutes long ........ Thanks again ..........

T-NYC's picture

... may equal Post - Stereophile. Enough PR BS. Stuart may need the money although his retirement should be secure via Meridian; notably Peter Craven is never part of these infomercials. Please, get back to reviewing magic cables & racks -- at least these do not debase the source material. And for an informed, impartial look at MQA try Archimago's Musings -- he's not selling anything -- not MQA licenses nor advertising.

dalethorn's picture

Archimaga is not selling anything? I dispute that. After all, the head of that site paid for his "article".

T-NYC's picture

Your comment is disingenuous. What does it have to do with his multiple objective reports containing lots of hard experimental data, both measurements and controlled listening tests, by himself and others? I mentioned his site purely because his articles are very well done, and link to many others doing similar experiments and thus are a much faster way to find many sources of hard data than Google. I suggest you read them and then ask him how much he earns from the site. My guess is not enough to pay for test gear; that this is truly an informed enthusiast's passion, unlike Stereophile which stopped being a thought-leader in the 1990s and has primarily served an industry PR function since. I'm okay with that except when it becomes ridiculously blatant as it has with MQA.

dalethorn's picture

Disingenuous you say? No - I challenged your assertion that "he isn't selling anything". Whether he's merely making a living and his employer is the actual seller makes no difference to the issue.

Archimaga had his chance to publish a clean article, but instead packed it with lots of personal angst. Now he can go back and clean all of that up and make it suitable for AES or IEEE or whatever, but the intent was and is clear from the beginning.

And besides, nobody I know is going to take the time to validate any of those "proofs". What we want to know is what effect is has on the sound, and is it likely to become a DRM tool. And as I posted elsewhere on this forum, it would be great if Bob and friends would organize a test event so many of us could test his encoder for bugs. We would NOT need access to any code or algorithms or other secrets - just the computers under Bob's watchful eye so that we can take a non-MQA file to the MQA coded state and see what the possibilities are.

T-NYC's picture

I am going to take your concerns at face value because you are not selling anything ;-0 You need to read his MQA thread and follow the links to others; not one article but roughly twenty. A pain because blogs show them in reverse order. You will find ample evidence that sound is affected. "Bob and his friends" are trying to sell this. If you read my AES post above you'll see -- no controlled listening tests THREE YEARS after the announcement. This is a scam, and if it were just more magic cable type nonsense it wouldn't matter because we can make choices about what we buy. MQA affects the source material. The record companies are enthused because MQA (like DSD) has a theme-song: "Buy It Again, Sam". However, this time around Lo-Fi is built in through a compressive algorithm of very limited application value, originally intended only to improve streaming sound and now being applied to CDs. Why would you compress a CD, adding artifacts?. Money, that's why!

dalethorn's picture

"You need to read his MQA thread..."

Erm, no, because it comes from a source that's not only unprofessional, but has unethical behaviors.

T-NYC's picture

he's a degreed EE and what is unethical about him?

dalethorn's picture

The source, boss, the source...

The CA guy, his "biggest" anti-MQA threads in the Whole World, and the unethical behavior that's been described at length here in previous months' topics.

I'm sure you can easily find what you need.

Archimago's picture

Re: Dale's comment.

1. I have no ties to the industry. My employer services the public and my day job is not audio related though my background training does allow me to say a few things related to this topic matter.

2. The "proofs" were reviewed by 3 others who have backgrounds in audio engineering and computer science.

3. Please... I don't think my writing was all that "packed with personal angst". I expressed what I thought needed to be said based on facts, reasonable opinions and I hope logical conclusions. I think the audiophile public can appreciate my perspective in the service of consumer freedoms amongst the sea of uncritical support from the audio magazines as if this were some kind of true "revolution" rather than an attempt at control, using techniques which actually decreased potential fidelity of playback. If the press actually addressed these issues directly and fostered debate, I would not need to say anything, would I?

dalethorn's picture

The problem here is not your facts. I've seen the charts and graphs and don't dispute them. How they are interpreted could be a problem, and if I remember correctly, your famous article added a lot of interpretation.

Archimago's picture

What's the point of charts and graphs if not for providing insights into the meanings, interpretations and explaining implications?

Whether one agrees with the interpretations I leave to the readers. But if one disagrees then by all means discuss the concerns rather than vague insinuations and insults.

dalethorn's picture

Your interpretations disagree wildly with others who've published articles here, which leads me to think that you'd get more respect for your articles if you could build some info-bridges to the customers here who might read those articles. I don't find them useful, albeit I am a tech person. [Flame deleted by John Atkinson]

Archimago's picture

Dale, the "info-bridge" has always been there. While there are elements to the purely subjective philosophy that I do not agree with, I can appreciate the opinions of those who hold on to that stance even if I disagree. No need to get angry.

The issue with MQA has to do mainly with the product itself and the way it's promoted. Just because it exists doesn't mean it's any good.

Flames are unnecessary Dale.

dalethorn's picture

Info-bridge means getting around the fact that your opinions disagree wildly with what I see published here. Anger and emotions have nothing to do with your disagreements, it's about the facts only.

Archimago's picture

Yeah I got a few buck for writing the article. It was the standard amount Chris gives for headline articles.

I don't think I need to divulge the exact amount just like I don't think anyone here should need to divulge how much they get for their writing.

I can however tell you that I make about 4x the amount per day at my day job. It took many hours to research that piece and time to double check with others 'in the know'.

No sir, money is NOT my motivation.

dalethorn's picture

Your motivation was never in question. Your interpretations of the graphic data can be questioned, not so much your motivation. The biggest problem is where the call for that article came from, and their motivation was made crystal clear as anti-MQA, end of sentence.

Personally, I see a lot of credibility on the pro-MQA side, and some - even if not an equal amount - on the anti-MQA side. My impression is that you're fighting a losing battle, and a big factor in that losing effort is alienating good people who also have serious reservations about it.

Archimago's picture

We'll see ultimately which side of history the debate settles on in the not too distant future I think.

I got a PM about writing an article to summarize concerns raised by a very long thread. Many have been critical of MQA for months if not years. I got a small amount of money for the review article. So what?

argyle_mikey's picture

How about a poll ?
Choices :
a). A monthly MQA article
b). A regular monthly review of a “budget” component (in the last year you’ve reviewed just 7).

Mike

jimtavegia's picture

better is better, but I could only hear the music starting at about 1:19 or the 1:20 point. As someone who does much recording and owns over 16 microphones, some with only 5db of self noise, I work very hard at the venue to listen for room noises and artifacts than can ruin my efforts.

It still seems to me that MQA is more about master control, but if it does ultimately sound better then the market will decide. The problem here is that if most of the major labels subscribe then WE don't get to choose other than buying a MQA capable DAC or not. I am not sure if this is the same as a DSD recording session mixed down for rebook sale. All of my SACD releases do have a rebook layer so I don't need an SACD player unless I want to hear the most. The price of entry into SACD player land is not cheap anymore and certainly not as cheap as gaining entry to hear MQA files. There is still much to be sorted here.

Ortofan's picture

... the Pioneer Elite BDP-80FD DVD unit will play SACD discs and costs about $300. Otherwise there are SACD capable audio players available from Marantz, Yamaha and Denon for about $1200.

adamdea's picture

I think Jim deserves some praise for putting to Bob Stuart some points which others have raised for some time.
I don’t know why Bob eschewed the opportunity to respond to Archimagos article but this filled in some of the gaps.
I have criticised Jim for not asking probing questions in the past, and so it’s only fair to give credit for getting Bob Stuart to address some of the issues. One might I suppose go as far as to draw an analogy with the Frost Nixon interview where, in advance Frost was seen by many as being too soft and lightweight.

In many ways I see Bob’s Stuart’s answers as a remarkable mix of evasion and white flag. Is that lack of pressing follow up questions a weakness or a strength? Perhaps Bob would only go on the record if he had confidence that his responses would be received uncritically.

Well, anyway I thought it was useful. Is it safe to assume that we now know what time smear is? Is it uncharitable to point out that this could not possibly justify the hype? Or that it is somewhat difficult to accept that this could be what Bob meant all along? Or to point out that if quantisation is the issue then cutting 16/44 to noise shaped 13 bit seems an odd sort of progress?

T-NYC's picture

https://www.researchgate.net/post/Is_Nyquist_Shannon_sampling_theorem_no...

Note: compressive sampling based on prediction NOT high-fidelity; very useful for mobile phone and similar where intelligible results not complete data reconstruction (AKA fidelity) is the goal.

T-NYC's picture

At AES 2017, Bob Stuart was asked if there had been any scientific listening tests performed on MQA. The question was from Bruno Putzeys, mathematical physicist & accomplished audio designer. The answer three years after the launch of MQA was no. The room got very quiet.

dalethorn's picture

A far better test (as I noted elsewhere) than merely listening to whatever "output" Bob would lay on the testers' desks would be to allow the testers to apply the codec to PCM files themselves (in Bob's lab of course), then listen to the before and after right there.

Bob would retain all secrets, and the testers would not only be able to validate the before and after results, they'd be able to try different things (within whatever are the allowable encoding parameters) to see what bugs might be hiding in the encoding software.

Archimago's picture

Controlled pre and post-MQA processing is what the supposedly upcoming study from McGill University is addressing. That will be interesting (if the results surface).

I don't think it's about bugs. Rather the differences we can already find on analysis of the decoded signal is by design and clearly are the results of a lossy process necessary for data reduction and the upsampled reconstruction.

dalethorn's picture

It's about bugs at some level if the industry becomes less demanding of quality, which is likely. Bad enough to have bad intent (if that's the case) in applying potential DRM, but it's even worse if further corruption creeps in due to bugs.

T-NYC's picture

DT, there is no interest in this (your proposition) at Meridian / MQA. It's been three years (see my post above). This is merde served fresh. BTW, again note Dr Peter Craven long ago disassociated himself from MQA. He has not been publicly involved since AES 2014. Ever wonder why? I do not know of a single physicist nor cognition-researcher who's work is with high-fidelity audio or touches on it who buys into this; quite the opposite.

dalethorn's picture

As Bob Stuart comes from audio and Peter Craven from math, is there something I should look for to tell me why Craven should be involved in MQA beyond the tech aspect of the code? I do recall that there were problems with early MQA releases and noise levels that was fixed, and many albums were remastered to accomodate that fix. I imagine Craven would have been involved in that. So I wonder - has Craven disassociated himself from MQA to the extent that if the codes need more work, he will not do any of that work?

Bogolu Haranath's picture

Since you wrote on this forum that you own many microphones and do many recordings, you may be interested about Ehrlund microphones. The transducer diaphragm in these microphones is "triangular" in shape. Probably the microphones you use have round diaphragm, which is very common. The company claims that their new type of microphone has superior "impulse response" and is better suited for recording. If you are not already aware of it, check out their website. They have a appox. 30 minute video posted on their website which explains the concept in more detail. Again, the name is Ehrlund microphones.

jimtavegia's picture

I am sure that due to high quality engineering that these new mics will sound good, acceptable, but I am concerned that the pistonic action with equal pressure being the driving force behind circular diaphragm designs. Until I had heard and used one I would pass no judgement other than it not being tried or used by other established companies, but that was a choice by their engineers and does in any way alter the performance of a new choice in design. The automobile industry has often had to result in differing speaker driver shapes due to space limitation and most often sound excellent.

I will try and find a dealer for an audition as changes and improvements are always welcome in trying to capture more in a recording event. Thanks.

Bogolu Haranath's picture

Hello ...... Me again ........ There is a new album by artist Morgan Agren, "Through the eyes of a Morgchestra" which I think is recorded using Ehrlund microphones ........ Check it out if you want to ......... I think it came out recently in 2017 .......... I did not explore all the new recordings by all the artists using these microphones (yet) ...................

jimtavegia's picture

The MP3 format will not allow much of a test. Is there a CD version for sale that you know?

Bogolu Haranath's picture

Thanks for responding to my comments ........ I don't know whether the recording is available in CD or not. You can check the Hi-Res download websites and streaming websites like Tidal ......... I downloaded it from iTunes ........ Well ...... It sounds good even with 256Kbs resolution ..........

dalethorn's picture

The artist says that the album you reference was created with a MIDI, but will be performed later by a symphony orchestra. So how can a person relate the quality of the microphones if there is no real acoustic sound?

Bogolu Haranath's picture

I don't know all the details of the recording ...... From what I understand the drums were recorded using Ehrlund "triangular" diaphragm mics ........ The artist Morgan Agren is a drummer .......... He has a video posted on You Tube and Google search .............

dalethorn's picture

I have a drum recording by 'Tutt-Keltner' that has a variety of high quality drum sounds suitable for evaluating the mics used for the recording. Listening to the album you've referenced, I don't get enough sense of drum "skins" in real space that I could make a judgement with. It just sounds electronic to me, unless you have a specific track from that album in mind that reveals acoustic drum sounds very clearly.

Bogolu Haranath's picture

You probably have lot more experience listening to music and drum sounds and various mics, than I do ...... There are several tracks I can hear drums ........ I can't recommend just one or a few tracks with good drum sound ......... You may wanna check the artist's website and videos and decide for yourself ...... I got this recommendation from a friend ..........

dalethorn's picture

I played quite a few tracks from the various Morgan Agren albums, but didn't hear anything I thought unusual.

On the other hand, Stereophile has (or had) a test CD that has Gordon Holt reading text into a dozen different pro mics, and the differences in their sound has to be heard - fascinating stuff.

Bogolu Haranath's picture

There is another album by the same artist released couple of years earlier ....... It is called "Batterie Deluxe" ....... It has drum sounds .......... I don't know whether it was recorded with the new mics ......... You may wanna check that one too .........

Bogolu Haranath's picture

Yes .... I do have that CD which I got many years ago ........... Sadly JGH is not around ......... So, we don't know how he sounds with these new microphones .......... If you can find any other albums of any other artists using these new mics, let us know .......... I sure will be interested .........

Bogolu Haranath's picture

This type of triangular diaphragm transducer would be great for headphones too .......... The diaphragm is supposed to cover very wide band width ......... This type of diaphragm could also be used for a single driver loudspeakers .......... Imagine that .........

Bogolu Haranath's picture

Till those types of headphones and loudspeakers are available, we may not be able to fully appreciate the full potential of these new types of microphones ............ I am all excited about the future of audio reproduction ............

dalethorn's picture

I've reviewed several hundred headphones, and published EQ curves (i.e. the inverse of a response curve) for most of those. Headphone response (ignoring in-ear types) varies pretty radically between the different models, and that's assuming a perfect fit with no issues.

While the advantages of better drivers (for example, the Focal Utopia) can be heard through the choppy frequency responses, the sonic differences in drivers are a very small factor compared to the ragged responses.

Note that this is not mere perception - if you check Innerfidelity's measured curves, you can even see large response differences between different samples of the same headphone! With speakers, you have much more flexibility in adjusting the speakers, the listening position, and the room treatments (including drapes, curtains, etc.)

Bogolu Haranath's picture

The ragged and choppy frequency response you mentioned is the ringing, I think ........... The round diaphragm may be the reason for this ........ Most of the headphone measurements show this kind of response usually from 1 KHz going up .......... For most of the loudspeakers the crossover is in this region between midrange and tweeter .......... Some of the harshness, smearing etc. audiophiles talk about happens in this region .......... some people attribute this to metallic tweeters ......... Also, some people blame this to digital recording .......... A square diaphragm shows less of this ringing phenomenon than a round diaphragm .......A triangular diaphragm shows even less of this ringing phenomenon than a square diaphragm .......... You can see all this being demonstrated in several videos on Ehrlund website ........ Some of the people listening to MQA, reported that they hear "smoothness" to the sound in this crossover region ........ Probably the MQA DSP is donig this .........Ehrlund website does not talk about MQA of course ...........

Bogolu Haranath's picture

This ringing probably is coming from the center of the round diaphragm, because round diaphragm starts "beaming" like a flash light as the frequency goes up ............ Round diaphragm has a wider area of sound dispersion and coverage at the periphery than the center portion ........ You probably already know all about this sound dispersion phenomenon ..........

dalethorn's picture

Take a look at this Stereophile article on a single-driver speaker. Note especially the reviewer's listening comments on page 2, for example: "The conclusion I eventually reached was that the tension I felt with speakers other than the ClairAudient 2+2 arose from subtle distortions caused by the crossovers and dissimilar drivers."

https://www.stereophile.com/content/audience-clairaudient-22-loudspeaker...

https://www.stereophile.com/content/audience-clairaudient-22-loudspeaker...

Bogolu Haranath's picture

I read that review a while back ...... The jagged and choppy response you mentioned is probably coming from the ringing ........... As you can see in the headphone measurements this kind of jagged response is higher in frequency say from 1 KHz and up .......... This is usually the crossover region between the midrange and tweeter .......... The ear is very sensitive in this region ........ This jagged frequency response does not happen with a triangular diaphragm, as shown on those videos .........

Bogolu Haranath's picture

One of the comments I made somehow disappeared from this forum ( I did not use any profanities) ........ Anyway .......... The comment is about ringing of the round diaphragm versus a square diaphragm versus a triangular diaphragm .......... The triangular diaphragm shows the least amount of ringing ......... All this information is available on Ehrlund microphones website ...........

dalethorn's picture

There's enough confusion here to make some things disappear, and part of that is because we're kinda off-topic with the microphone stuff. I am going to look closer at the Ehrlund microphone site to see how they're progressing.

dalethorn's picture

OK - taking a long look at the Ehrlund mic reviews, some by people I know like the Tapeop and Gearslutz guys, the overall impressions are an excellent mic, comparable to the best, with the most obvious differences from perceived neutrality being the emphasized top end and possibly a slight shyness in the lower treble/presence region. Based on what I know about current mastering and some of the high-end headphone tunings like the Focal series or AudioQuest models use, the Ehrlund looks like a great mic for piano, organ, percussion etc.

One reviewer noted his difficulties with trying to record acoustic guitar with the Ehrlund, and apparently gave up. But another reviewer noted similar difficulties and how he fixed the problem, so perhaps the Ehrlund can work well with acoustic guitars if the right pickup is used. In any case, I was looking for specific gotchas, and didn't find any fatal weaknesses from those reviews.

Bogolu Haranath's picture

Thanks for your response ......... I was trying to connect all the dots ........ We all know that the two weakest links in the audio chain are the microphone at one end and the headphone/loudspeaker at the other end .......... What if ultra low distortion diaphragms are used for both? ......... Won't that be great for audio recording and reproduction .......... Think about it ..........

Bogolu Haranath's picture

Agreed ....... I own Focal Utopias which I purchased about a year ago ........ I very much enjoy listening to them ........ I also own Audeze Lcd -4, Lcd-x and recently acquired Lcd-Mx-4 .......... I also own AQ Night owls .......... Lcd-4 is the best in bass reproduction ........... Others are also good in various other ways especially in easy drivability ........ I am a frequent visitor to Innerfidelity website ......... None of the headphones available today have "flat" frequency response from 20Hz to 20 KHz ........ For that matter none of the loudspeakers available today have "flat" frequency response from 20 Hz to 20 KHz ......... These new microphone "triangular" diaphragm transducer is supposed to have "flat" frequency response from below 20 Hz to well above 20 KHz ........... That is why I am excited, if and when some company(s) come up with the "triangular" or some other different shaped transducer(s) for the headphones and loudspeakers we may not experience the full potential of audio recording and reproduction ........ To paraphrase the great JGH, "down with the round", may be not down with "flat" ........

Bogolu Haranath's picture

I forgot to mention ........... I also own a pair of Westone W-60 in-ear universal fit model .......... I am working on a custom fit model ............

Bogolu Haranath's picture

When the ultra low distortion transducers become available, we can always use external EQ and DSP to suit personal listening tastes and preferences ......... It is like putting icing on a great cake ........ The cake has be great to begin with .........

Bogolu Haranath's picture

Think about it ........ "Perfect sound forever" is possible in the very near future ......... If you can believe it ..........

mrkaic's picture

Is this MQA algorithm published anywhere? I'd like to see the equations and analyze it myself.

dalethorn's picture

It's more closely guarded than the schematic for the NASA warp drive.

Indydan's picture

You're confusing NASA with Star Trek...

Bogolu Haranath's picture

It is proprietary DSP I think ........ They have patents for it .........

Bogolu Haranath's picture

Do we need a "special counsel" appointed to investigate this? .......... Is there some kind of "collusion" between the audio press and MQA? .............

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