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MQA Deep Dive - I published music on tidal to test MQA

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raistlin65

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It could have trivially done that as well. But the market doesn't want that. The market wants the files as created in the "studio" as that sounds like it is better. What you are saying is why the hotel customer doesn't drink tap water instead of paying $5 for the Fuji bottle on the table. Even if they taste the same, some want the Fiji water thinking they are in a paradise for a minute or two. :) Don't change the value prop and then ask why they did this. They did it because there is market demand.
That's an apt analogy, but your analysis is incorrect. The expensive bottle water demand wasn't addressed. It was invoked by the beverage industry who created the demand. There's no health benefit to it for consumers over inexpensive bottled water. But the beverage industry makes money off of it. And I wonder how many people have done blind tasting tests to see if they can tell the difference between the more expensive bottle water and less expensive brands?

Sounds like MQA, right? MQA created the demand. And there's no benefit to consumers, but MQA is certainly going to make their money off it.

And by the way, it's Fiji water, not Fuji water. I'm not really into playing grammar Nazi. But this stuff has an absolutely awful carbon footprint and other issues, so it really shouldn't be described lightly with a smiley face: https://www.newuniversity.org/2021/03/10/the-dark-secret-of-fiji-water/
 

artburda

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That's an apt analogy, but your analysis is incorrect. The expensive bottle water demand wasn't addressed. It was invoked by the beverage industry who created the demand. There's no health benefit to it for consumers over inexpensive bottled water. But the beverage industry makes money off of it. And I wonder how many people have done blind tasting tests to see if they can tell the difference between the more expensive bottle water and less expensive brands?
Actually, I participated in a blind water testing a few years ago at university. It was part of a presentation on the subject of "green washing", so not really a controlled study or something like that. The waters were in identical plastic glasses. However, you really could differentiate the different waters, especially the Fiji water. A lot of participants in the audience could point out which one was the Fiji water. But to this day I have never bought a Fiji water, so that's that.
 

tmtomh

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New member here, involved in a long running parallel thread on pinkfishmedia.

I think this simple look can elucidate the great lossy/lossless debate. We are leaving MQA's "deblurring" process out for now, since this a separate debate/controversy.

Let's put some numbers on the distortion expected in the types of codecs helpfully explained by Amir. In engineering, a useful excercise is called "order of magnitude analysis." It allows one to get approximate understanding of system behavior.

Mathematically Lossless Codec:

Mathematically perfect algorithm running on a real-world computer and network, will still have an error once in a great while. Let's pick a really tiny value - 1 in a billion or 1E-9. This results in the error against the original file of -180dB. Great performance!

Lossy codec:

Let's stipulate a very good algorithm that delivers an error of 1/10 of 1% or 0.001. This results in the error against the original file -60dB. Not bad at all!

MQA:

From graphs posted at PFM and elsewhere, "eyeball" MQA null against LPCM looks like -120dB, or 1 in a million (1E-6). This is clearly better than an excellent lossy codec but clearly not as good as mathematically lossless one.
https://drive.google.com/file/d/1o79kijUug1Rg3Ne0aHM35oibMMPbWRK6/view?usp=drivesdk
(Red and Blue curves used for conservatively deriving 120dB number. Yellow vs. Green maybe more relevant and seem to overlap up to 35 KHz even more. If properly averaged and weighted the final number is likely to be smaller - i.e better null).


Let's consider what above numbers mean in the context of consumer audio replay:

Leaving aside a question of when do deviations become audible, one still needs a sound system that has amplification with low enough distortion and noise to actually playback these differences.

I own modern amplifiers with very low distortion and very high power - Emotiva XPA-1 gen.2. Their specifications list Signal to Noise at 89 dB at 1 watt and 117dB at full power (600w). Let's take an average of 103dB. Added distortion, though very small (-80dB), will make the total number worse.

So on my very low distortion system, I could at least theoretically be able to hear distortion in the lossy codec. However, both mathematically lossless and MQA distortion will be below the system's noise/distortion floor and, therefore, inaudible.

They will be entirely indistinguishable from one another to the listener and are, therefore, identical. The big debate about MQA lossy/lossless status is entirely meaningless for consumer reproduction.

I note that a lot of MQA criticism is essentially someone showing you some hard to see plots and insinuating that *something* is bad. In engineering we call it "arm waving." Once you put some numbers on the observed phenomena and place it in the context of actual system operational usage, one can make informed conclusions. Simple excercise above shows that mathematically lossless and MQA are identical in the context of home listening.

I welcome mansr and others to offer a competing simple analysis that challenges above numbers in a meaningful and substantial way.
First off, welcome to the forum!

As to your analysis and argument here, I personally lack the technical expertise to evaluate it definitively. I will say that it certainly seems reasonable, and the idea that we must evaluate measurable sonic differences in the context of audibility is one that is routinely used and agreed to here - in other words a measurable difference between two things (pieces of equipment, codecs, whatever) is not significant or important if we can be confident that the measured difference is below the level of audibility.

Where your argument runs into a problem, though, is when we come to the next question: Let's say MQA is audibly indistinguishable from conventional PCM. I am not ready to concede that definitively, but let's concede it temporarily for the sake of discussion.

If MQA is sonically identical for all intents and purposes, then two questions naturally present themselves:

  1. Is there any non-sonic reason to prefer MQA over other formats? In other words, do we need MQA?
  2. Is there any non-sonic reason that MQA might actually be actively detrimental? In other words, does MQA create problems for music consumers that could be effectively addressed if MQA disappeared?

To the first question, your analysis clearly shows that the answer is No - we don't need MQA. It solves a problem that doesn't exist, it produces none of the audible benefits MQA (the company) claims for it, and so on.

After we have answered question #1, we are essentially at a point where we share @amirm 's position: MQA is of no great consequence sonically and of no great consequence non-sonically - it's just another codec/format, so why bother worrying about it or trying to get people to come down strongly for or against it?

The problem is question #2, to which the answer is clearly Yes. There are several reasons that MQA's existence and presence in the marketplace can be seen as not simply neutral or unnecessary, but actively negative and problematic:

  • It pollutes the audiophile streaming pool. It has been shown that Tidal's lossless, non-high-res tier includes MQA files, which in that subscription tier cannot be decoded. And whatever one thinks about the audible performance of unfolded or fully rendered MQA content, undecoded MQA content plays back at a bit depth that is inferior not only to 16-bit redbook, but based on the analysis of @mansr, @Archimago and others, apparently even worse than Philips' original 14-bit proposal for the format. With 13 bits of effective depth, undecoded MQA is basically taking things down to the level of high quality analogue reel to reel tape (albeit with better speed accuracy of course). This makes a complete mockery of the entire purpose of this site - if you are regularly playing 13-bit content, then who cares if a DAC's SINAD and linearity are 16 bit vs 21 bit? Using the principle - voiced by Amir and others in many contexts and threads - of 10dB of headroom, a DAC that provides only 15 bits' worth of SINAD and linearity is perfectly sufficient to play 13-bit digital content. You can get a DAC that Amir would describe as a broken implementation and still not come anywhere close to reducing the fidelity of an undecoded MQA file. That is, to put it politely, an undesirable scenario for 99% of the members here - and I would say most people would call it simply unacceptable.
  • It creates new, mostly hidden costs for equipment. Except for some Topping gear that's available with and without MQA capability, MQA raises the price of equipment because it imposes licensing fees. Whether we pay more for the product or companies absorb the cost is irrelevant. We pay more, or else companies have less to spend on R&D, engineering, build quality, other features, or whatever. If it adds cost and provides - per point #1 above - no sonic benefit, then it's parastic and undesirable.
  • It potentially compromises the sonics of everything that goes through an MQA-enabled DAC. For those DACs that keep MQA's digital reconstruction filter permanently engaged, MQA means that all of your music is locked into using that filter. Slow, leaky filters like MQA's are detrimental to the sonics of the audio band because they increase aliasing, which creates needless distortion. Amir consistently points this out - and his recent claim not to want to comment on MQA's filtering makes no sense since he routinely comments quite clearly on MQA-style filtering; he quite rightly condemns it.

Now, for whatever reason, Amir has chosen to take all of these objections to MQA and lump them under the heading of "people who are not in the industry waving their hands and not understanding how the business works and not understanding technology." That is not a persuasive argument, and I'm honestly mystified as to why he is so insistent on making it.

Regardless, the issues mentioned here - and not stupidity or ignorance - are why the MQA discussions persist.
 
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tmtomh

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It could have trivially done that as well. But the market doesn't want that. The market wants the files as created in the "studio" as that sounds like it is better. What you are saying is why the hotel customer doesn't drink tap water instead of paying $5 for the Fuji bottle on the table. Even if they taste the same, some want the Fiji water thinking they are in a paradise for a minute or two. :) Don't change the value prop and then ask why they did this. They did it because there is market demand.
Yes - but you need to continue the analogy. If you were the founder and operator of a web site called Water Science Review and your entire purpose was running scientific tests on different brands of water and you found that the $5 premium water bottles contained water that was no purer - and in some cases even less pure - than tap water from properly designed, properly maintained municipal systems, you would say so.

And when members of your forum pointed out the flaws in those premium water brands' claims, you certainly wouldn't dismiss those flaws as unimportant and claim that your members were raising them only because they were ignorant and didn't understand the water market.
 

abdo123

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Yes - but you need to continue the analogy. If you were the founder and operator of a web site called Water Science Review and your entire purpose was running scientific tests on different brands of water and you found that the $5 premium water bottles contained water that was no purer - and in some cases even less pure - than tap water from properly designed, properly maintained municipal systems, you would say so.

And when members of your forum pointed out the flaws in those premium water brands' claims, you certainly wouldn't dismiss those flaws as unimportant and claim that your members were raising them only because they were ignorant and didn't understand the water market.
this is not the same at all to be honest, it's more like comparing distilled water to chlorinated water and saying that both are completely healthy, and are both absolutely clean from life threatening germs. but distilled water is obviously the 'clean lossless' version.

and when MQA says they're better than lossless they are indeed better (not necessarily to the consumers) because they're smaller and easier to maintain on servers and give perceptually the same thing anyway.

but when they advertised their chlorinated water as distilled water that's a big no no. even if it is in practice no harm done.
 

voodooless

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this is not the same at all to be honest, it's more like comparing distilled water to chlorinated water and saying that both are completely healthy, and are both absolutely clean from life threatening germs. but distilled water is obviously the 'clean lossless' version.
Disclaimer here: don’t drink distilled water, it’s not healthy and can cause dehydration ;)
 
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I saw a number of points/questions written about things that I'd see referenced in MQA's material (including how they treat the various ranges being discussed on this page). So I figure, why not go straight to their videos on YT and see what they have to say, so we're talking apples to apples, here, and in a format that is easily readable and provides direct quotes.

Transcribing some of Bob Stuart's answers from a recent YouTube video posted May 1, 2021:

MQA (Master Quality Authenticated) explained (sponsored): youtube.com/watch?v=8L8Vo8_gKQQ
(Bob Stuart)

06:03+:


7:29+


8:21+





14:02+



MQA – An Introduction: youtube.com/watch?v=3i69U69pqu0
(Spencer Chrislu)

What is MQA?


What is the science behind MQA?


What is blurring?


What makes MQA such a small file?


What is authentication?



MQA Music Origami: youtube.com/watch?v=BrgjycGhoSM
(Bob Stuart)











MQA - Ringing and Filters: youtube.com/watch?v=drv9ESli5yI
(Bob Stuart)







From MQA's previous version of "Is MQA Lossless?" https://web.archive.org/web/20210515030602/https://www.mqa.co.uk/newsroom/qa/is-mqa-lossless






It has been since updated to:


With the elaboration:
Horrifying and hilarious at the same time. Thank you for spending the time and effort to transcribe all of that.
 

tmtomh

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this is not the same at all to be honest, it's more like comparing distilled water to chlorinated water and saying that both are completely healthy, and are both absolutely clean from life threatening germs. but distilled water is obviously the 'clean lossless' version.

and when MQA says they're better than lossless they are indeed better (not necessarily to the consumers) because they're smaller and easier to maintain on servers and give perceptually the same thing anyway.

but when they advertised their chlorinated water as distilled water that's a big no no. even if it is in practice no harm done.
For 99% of its existence, MQA has said - falsely - that it is lossless. They only changed to "better than lossless" in the last week or two, obviously in response to the discussion prompted by @GoldenOne 's video and posts, which both Stuart and Amir have dismissed largely with ad hominem attacks on GO as a "blogger" seeking "sensationalism." So let's acknowledge first of all that the goalposts were moved by MQA, not only long after all of the criticisms against it were made, but also because of those criticisms.

Putting that aside for the moment, you've corrupted the analogy because you removed the extra cost of the "premium" product. If the chlorinated water were more expensive and claimed to be superior to the "clean lossless" water, it would be a bad deal. And if the chlorinated water company claimed it were "cleaner than clean," we would rightfully call BS on that - and so would Amir.
 
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amirm

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That's an apt analogy, but your analysis is incorrect. The expensive bottle water demand wasn't addressed. It was invoked by the beverage industry who created the demand. There's no health benefit to it for consumers over inexpensive bottled water. But the beverage industry makes money off of it. And I wonder how many people have done blind tasting tests to see if they can tell the difference between the more expensive bottle water and less expensive brands?

Sounds like MQA, right? MQA created the demand. And there's no benefit to consumers, but MQA is certainly going to make their money off it.
No it doesn't sound like MQA. Demand for high-res audio has existed for decades. Remember SACD and DVD-A formats? They died and got replaced with lossy audio online. Fidelity went down instead of up. Tidal took the initiative to push high-res online and did so with MQA. That likely had an influence on big guys trying to now offer high-res. And they are offering it without MQA. So no way you can put the market demand at the feet of MQA. They are providing a solution just like MPEG-2 AAC did by enabling high sample rates and bit depths decades back. And unlike Fiji water, they are not trying to charge $5 for a penny worth of water. People selling massive DSD and PCM files online are doing that to some extent and again, without MQA.

MQA's pitch is that it is a more efficient way of doing the delivery.
 

tmtomh

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No it doesn't sound like MQA. Demand for high-res audio has existed for decades. Remember SACD and DVD-A formats? They died and got replaced with lossy audio online. Fidelity went down instead of up. Tidal took the initiative to push high-res online and did so with MQA. That likely had an influence on big guys trying to now offer high-res. And they are offering it without MQA. So no way you can put the market demand at the feet of MQA. They are providing a solution just like MPEG-2 AAC did by enabling high sample rates and bit depths decades back. And unlike Fiji water, they are not trying to charge $5 for a penny worth of water. People selling massive DSD and PCM files online are doing that to some extent and again, without MQA.

MQA's pitch is that it is a more efficient way of doing the delivery.
Can you please clarify whether or not you think undecoded MQA is an acceptable or desirable format for digital music delivery for hi-fi purposes?
 

amirm

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If MQA is sonically identical for all intents and purposes, then two questions naturally present themselves:

  1. Is there any non-sonic reason to prefer MQA over other formats? In other words, do we need MQA?
  2. Is there any non-sonic reason that MQA might actually be actively detrimental? In other words, does MQA create problems for music consumers that could be effectively addressed if MQA disappeared?

To the first question, your analysis clearly shows that the answer is No - we don't need MQA. It solves a problem that doesn't exist, it produces none of the audible benefits MQA (the company) claims for it, and so on.
Huh? I just showed you how MQA cuts file size substantially relative to Flac:



The MQA version maintains the music content instead of all the ultrasonic noise and is able to achieve much better compression ratio. And contrary to what someone says, it is absolutely comparable to 176 kHz because there is nothing to encode above 88 kHz so it just does a resample to get the DAC to play at that sample rate.

You didn't just go through downloading those files to see the large difference in wait time as I did. Try to download some of the monstrosities out there like DSD256. We are talking insane file sizes there. MQA convinces the high-res seeking audiophiles that MQA is all they need. If they succeed it means that we don't have to distribute those insane file sizes for high sample rate PCM and DSD. This is pro consumer and pro music distributors. It is the reason MQA has gotten the design wins it has.

Your premise that MQA is sonically the same is also incorrect and not backed by any science. As I post, Stuart et. al. published peer reviewed paper that demonstrated audibility of filtering high sample rates to lower. You don't have anything like that. So no way you can make that claim.

Now, for whatever reason, Amir has chosen to take all of these objections to MQA and lump them under the heading of "people who are not in the industry waving their hands and not understanding how the business works and not understanding technology." That is not a persuasive argument, and I'm honestly mystified as to why he is so insistent on making it.
You just demonstrated why. We keep reading these talking points the anti-MQA camp has put together as if they are true and well-researched. They are not in the slightest.

Then comes the bit about me. You do realize that all of my dashboard tests for DACs uses 24-bit signals, yes? If I did not, the highest SINAD would be 97 dB! Look at my SINAD graph:



The cut off for orange to green is 100 dB. If I used 16 bit format, nothing to the left of the orange bucket would exist and part of that bucket would be truncated as well. All the work that is put in there to achieve transparency and reduce noise and distortion would be thrown out the window. As much as I advocate best in class hardware execution, I also advocate best in class content format and 16 bit 44.1 is NOT it. It never has been.

Anyone who wants to make these arguments needs to first get educated by reading and understanding Bob Stuart's paper I cited before:
Coding for High-Resolution Audio Systems*
J. ROBERT STUART, AES Fellow

And pay attention to graphs like this:

1622396573563.png


You see how threshold of hearing is exceeded with 16 bit content? See how the threshold of hearing is there which is created using psychoacoustic research and listening tests?

Is 16/44.1 'good enough?' Sure. It is. So is a $9 dongle. We could close the forum and that will be that. But personally I like us to strive for excellence. It costs nothing in most cases. Why on earth do we make content owners filter down 24 bit to 16 bit for example? What possible need is there for them to continue to do that in the age of online delivery as opposed to fixed CD standard?

Most video production is done at 48 kHz. Why do we force that converted to 16 bit if we want to release that soundtrack?

A 16 bit/44.1 kHz channel was wonderful and great for its time in CD. It was a massive improvement over analog formats. But time has come to let go of it and let the original content be delivered. If it is PCM format, I take it. If it comes in MQA, I take it. I feel better either way knowing that someone in some place did some format conversion that was a) never documented and b) who knows if it is optimal.

Bottom line, you have built a bunch of arguments on faulty, non-researched positions. Don't use them as assumptions and then run with them. This has been the problem from day one on these MQA arguments. Learn the topic and don't run with talking points. Above all, don't repeat them over and over again when they have been addressed.
 

amirm

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Can you please clarify whether or not you think undecoded MQA is an acceptable or desirable format for digital music delivery for hi-fi purposes?
I have not done controlled testing of undecoded MQA versus original to know the sonic effect. Objectively it is a degradation.

Decoding MQA though is free both in Tidal app and in Roon. So the question is, does it matter? MQA says the process of adding MQA bits to baseline layer is reversible and lossless. If so, then we are getting more, not less with that addition if you decode the MQA. Which again, those of us who consume MQA do.

Has anyone who complained about the impact on undecoded streams done listening tests? If not, why not? You are making that a huge part of your argument. Why don't we have listening test data to back your complaints as far as impairment?

Note that I have done my complaining on the objective side in my youtube video.

Let's see a few ABX test outputs on who can pass it and what they are hearing different. Don't wait on me on that. You don't need me for any of this type of testing.
 

tmtomh

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Huh? I just showed you how MQA cuts file size substantially relative to Flac:



The MQA version maintains the music content instead of all the ultrasonic noise and is able to achieve much better compression ratio. And contrary to what someone says, it is absolutely comparable to 176 kHz because there is nothing to encode above 88 kHz so it just does a resample to get the DAC to play at that sample rate.

You didn't just go through downloading those files to see the large difference in wait time as I did. Try to download some of the monstrosities out there like DSD256. We are talking insane file sizes there. MQA convinces the high-res seeking audiophiles that MQA is all they need. If they succeed it means that we don't have to distribute those insane file sizes for high sample rate PCM and DSD. This is pro consumer and pro music distributors. It is the reason MQA has gotten the design wins it has.

Your premise that MQA is sonically the same is also incorrect and not backed by any science. As I post, Stuart et. al. published peer reviewed paper that demonstrated audibility of filtering high sample rates to lower. You don't have anything like that. So no way you can make that claim.


You just demonstrated why. We keep reading these talking points the anti-MQA camp has put together as if they are true and well-researched. They are not in the slightest.

Then comes the bit about me. You do realize that all of my dashboard tests for DACs uses 24-bit signals, yes? If I did not, the highest SINAD would be 97 dB! Look at my SINAD graph:



The cut off for orange to green is 100 dB. If I used 16 bit format, nothing to the left of the orange bucket would exist and part of that bucket would be truncated as well. All the work that is put in there to achieve transparency and reduce noise and distortion would be thrown out the window. As much as I advocate best in class hardware execution, I also advocate best in class content format and 16 bit 44.1 is NOT it. It never has been.

Anyone who wants to make these arguments needs to first get educated by reading and understanding Bob Stuart's paper I cited before:
Coding for High-Resolution Audio Systems*
J. ROBERT STUART, AES Fellow

And pay attention to graphs like this:

View attachment 132753

You see how threshold of hearing is exceeded with 16 bit content? See how the threshold of hearing is there which is created using psychoacoustic research and listening tests?

Is 16/44.1 'good enough?' Sure. It is. So is a $9 dongle. We could close the forum and that will be that. But personally I like us to strive for excellence. It costs nothing in most cases. Why on earth do we make content owners filter down 24 bit to 16 bit for example? What possible need is there for them to continue to do that in the age of online delivery as opposed to fixed CD standard?

Most video production is done at 48 kHz. Why do we force that converted to 16 bit if we want to release that soundtrack?

A 16 bit/44.1 kHz channel was wonderful and great for its time in CD. It was a massive improvement over analog formats. But time has come to let go of it and let the original content be delivered. If it is PCM format, I take it. If it comes in MQA, I take it. I feel better either way knowing that someone in some place did some format conversion that was a) never documented and b) who knows if it is optimal.

Bottom line, you have built a bunch of arguments on faulty, non-researched positions. Don't use them as assumptions and then run with them. This has been the problem from day one on these MQA arguments. Learn the topic and don't run with talking points. Above all, don't repeat them over and over again when they have been addressed.
Will look forward to reading your tests of undecoded MQA and unfolded MQA to see what the noise floor of each format is and how that compares with 16-bit PCM and 16-bit PCM with noise-shaped dither.

As for 16 bits not being sufficient to reach the limits of human hearing, no need to remind me of that - I'm fully aware, as is every other halfway technically literate member of this form who is critical of MQA. The question is whether MQA files - undecoded and unfolded - achieve a true 120dB noise floor with at least 20 bits' worth of noise-free depth (or 20 bits' worth in the frequencies where we're most sensitive, if you prefer).

Also, when we compare the file size of MQA and 24/48 PCM FLAC - a format with sufficient bit depth/noise floor and plenty of ultrasonic room for any decent filter - what is the file size savings of MQA compared with that?
 
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