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

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Jimbob54

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Rich,
You need to read the papers of MQA to understand why they are capturing ultrasonics (some of them a bit dubious, I recognize, such as the non-audible perception of these frequencies). And, btw, this argument would invalidate any sample rate higher than 44.1 Khz... I bet everybody here do believe HD files sound better than Redbook.

Actually, of the people that are vocal on here , I think the majority would say they see (hear?) no need for HD. Personally, I'll take it if I can get it, but I havent gone to the extent of doing any proper testing. I do know I struggle to tell between higher rate aac/mp3 and redbook.
 

levimax

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I see no way of being able to maintain full unfold capability, and applying PEQ in the digital realm for MQA. Unless I'm missing something blatantly obvious here or whatever.
MQA does not need room EQ. Since it can read dead peoples minds about their "original intentions" it is Childs play to know what EQ your room needs.
 

mieswall

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Are you feeling OK? That amount of nonsense in one person can't be healthy.
Perfectly fine, thank you for your concern.
Are you listening too much to Jethro Tull? 'Living in the Past' perhaps? Are you aware you are living in 2021 and not in Rouen, France, year 1431?
 

Raindog123

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You may need, say, 15 bits to capturing all the dynamics happening at 30 Hz, but only a fraction of that at 15 Khz (4, 5 bits perhaps?). What MQA does is, again, regain that wasted bit-depth to store relevant information coming from upper folds.
While at the core of your explanation, this is a rather simplistic and naive interpretation: "Unconditionally", it is only applicable to constant (test) signals, single or multi-tone. That yes - can be represented by a constant Fourier spectrum, with various frequencies assessed against the energy present in them. However. The "actual music" (regardless of genre) changes all the time - thus produces constantly changing Fourier "waterfall". (With the time-constant of this change is defined by the Fourier transform window used - as the actual music dynamic is typically higher.) The "envelope" of this spectrum (eg, through the duration of the music piece) is actually rather uniformly distributed. While instantaneous "time slices" - those ultimately defining the dynamic range - being all over the map, from non-existent (at noise floor) to the max. So, without a clearly defined [MQA] algorithm and the time-scale it operates on, the above statement - of 15bit at 30Hz vs 5bit at 15kHz - is just a "nice conceptual hand-waving".

That "slice" or "window" of relevant information, btw, is not static, but dependent on the content to be packaged. ... could be problematic with a very limited kind of music throwing persistent high frequency energy (only possible with artificially generated tones), but for the 99.99% of the rest of music content, it is perfectly good... and lossless in its content.

Again, I would recommend you (and all of us) to look at the spectrum-as-a-function-of-time (“the waterfall graph") of a symphonic orchestra recording. Or of any complex-enough music piece, for that matter. Both at its envelope and dynamics (defining the dynamic range). It is rather eye-opening - as many of us are only custom to simple single-tone (sine) responses, or such... Eg, there are examples of such waterfalls in @GoldenOne's analysis.

... How does MQA assumes what is relevant from what is not? ... it is not difficult to envisage even if you don't read them: Any Fourier decomposition of the music signal gives a clear statistic of the amplitudes you need to capture. But even without it (as in analog-to-digital capture in real time), you know in advance that ALL instruments (with except of some tones of synthesizers) have lower amplitude harmonics.

See my points #1 and #2... And don't even get me started about complexities of [additive or subtractive] multipath, interference, resonances, intermodulation (and other very real effects in recordings at indoor & outdoor venues), and even Doppler (yes, Doppler, in some very real recording cases!) :)
 
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RichB

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Rich,
You need to read the papers of MQA to understand why they are capturing ultrasonics (some of them a bit dubious, I recognize, such as the non-audible perception of these frequencies). And, btw, this argument would invalidate any sample rate higher than 44.1 Khz... I bet everybody here do believe HD files sound better than Redbook. One of the purposes (but not the only one) is to move the Nyquist frequency much higher in the spectra, as to avoid that the phase-shift anomalies of filters applied in the ADC conversion to fall in the audible region, thus obtaining the audible band with all the harmonics in full time-coherence with its fundamentals. That's why they must work from masters for a better MQA file, btw.
.

Lacking the energy to comment on your subsequent post, I'll stick to this section.

Digital filters
I am willing the accept that digital filters can have an audible effect, especially, since implementation matters and they clearly differ. There are hundreds of measurements on ASR showing filter differences. Likewise, higher sampling frequencies can push out phase changes. I would not say this is proven, but there is a possibility.

Sampling Frequency
A file either has a higher sampling frequency or it does not.
Consuming dynamic range in order to simulate the extended frequency response is not the same.
Timing cannot be improved by lowing the sample frequency. There are smarter folks here than I than can attest to that.

HD Audio
I'll bet everybody here does not believe the HD-Audio sounds is better than Redbook.
Again, one system may perform wall with ultrasonics and another may not.
Mastering improvements, removing excessive compression digital clipping, and overages matter a great deal.
Of course, even HD-Audio does not concern itself with demonstrable quality metrics.

At least, HD-Audio files do not have a demonstrable performance loss and licensing restrictions.
There are those that pass the "keys" test with the HD-Audio and Redbook (I guess we call that SD-Audio :)).
That could be due to filtering or it could be due to artifacts produced by the playback chain.
Identifying a difference, does not mean better or more accurate.

ADC Conversion (or Analog to Digital Conversion Conversion :p)
There is no evidence that MQA identifies timing issues with the AD Conversion.
You can find sources that are mic'ed and converted with one ADC.
The vast majority of recordings are multi-track with a ton of mastering tools applied.
Give me a break.

So you see, MQA is, on all counts, a farce. They began by lying and calling it lossless.
This is from the folks who invented MLP (lossless packaging) forgot that it was lossy.
No, they lied to make money and got called out.

Tidal seems to be in CYA mode. their MQA tracks are "Master" quality.
That sounds nice and I guess it is shorthand for MQA.
Why not just call a duck a duck and brand it as MQA? There must be a reason.

Here is a though experiment. If MQA could make royalties on lossless HD-Audio they would be debunking MQA as fake and inferior.

- Rich
 
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sq225917

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If filters have issues folding back around the nyquist frequency then plain old upsampling shift this out of the upper audible band with ANY need for additional tomfoolery or discarding hard fought for snr or dynamic range.
 

RichB

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I can not believe it, but just for fun (and to remember this messy propaganda):
Is MQA lossless

:facepalm:

Thanks for that. I remembered the original lossless claim while at the same time claiming have moved past old fashioned ideas of lossless and lossy.

Then there is a link to Bob Talks. Hey, no problem with any of this, he is a really nice guy with many bills and grandchildren that need an inheritance. Let's cut them some slack folks and keep your facts and measurements in check.

- Rich
 

Jimbob54

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Rich,
You need to read the papers of MQA to understand why they are capturing ultrasonics (some of them a bit dubious, I recognize, such as the non-audible perception of these frequencies). And, btw, this argument would invalidate any sample rate higher than 44.1 Khz... I bet everybody here do believe HD files sound better than Redbook. One of the purposes (but not the only one) is to move the Nyquist frequency much higher in the spectra, as to avoid that the phase-shift anomalies of filters applied in the ADC conversion to fall in the audible region, thus obtaining the audible band with all the harmonics in full time-coherence with its fundamentals. That's why they must work from masters for a better MQA file, btw.

BTW, if these flawed tests of Archimago or GoldenEar show something, it is precisely that they confirm some of the things that MQA says in their papers:

1- The anomaly of ripples in the square wave response is exactly what is expected to happen if you are aware that MQA is expecting less dynamics at higher frecuencies (as by definition happens with all music), and thus, using smaller effective bitrate in that part of the spectrum (the rest of the 24-bit word used as room for origami folds). If you model a square wave in a wave simulator, and then start reducing amplitude of higher harmonics, that's almost exactly what you should get.

2- The fact that Archimago obtained larger MQA files when the input was a 16/44 shows that the most compressible areas for a Flac (void information), may in fact be used by MQA to store information coming from the upper folds of the origami, and so, less compressed. That, and that the file is of 24bit depth instead of 16, of course...

3- The anomaly in the spectrum of Archimago surrounding 22 Khz... which happens to be the Nyquist frequency (22.05 Khz in a Redbook). One of the process that MQA is trying to achieve is to eliminate the aliasing that ADC normally generates around the Nyquist frequency. If presented with flawed information, probably the MQA process prefers to just erase a tight band around de Nyquist frequency instead of leaving the aliasing artifacts that would be much more perjudicial.

4- I think it is extremely interesting the see-saw response (completely inaudible, btw) in his pure sine wave plot. It may show that MQA is using some kind of sigma-delta-like process in the conversion, as that pattern if typical of the reversing polarity of a significant 1-bit around a predefined margin of the signal. I haven't seen this described in what I've read of MQA. If not, inadvertently GoldenEar may have disclosed an interesting fact about how MQA is working. I would test this at several frecuencies to see what happens in each one in this respect.

I've done a really shoddy poll to address what you said in the first para about hi res sounding better than redbook to people on here . https://www.audiosciencereview.com/forum/index.php?threads/poll-hi-res-music.22637/page-2 Early days but looks like the majority of responders say they cant discern a difference.
 

sandymc

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That's why they must work from masters for a better MQA file, btw.

Which is what GoldenOne's test indicates they don't do............so is the argument here that MQA would be great but the problem is that Tidal is doing MQA all wrong? Or what? Because it seems clear that in practice, as indicated by the Tidal results, MQA has some reasonably major problems when measured against the claims made for it. That can only be (a) because MQA in principle can't deliver those benefits, or (b) because the specific Tidal implementation is in some way defective.
 

RichB

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I've done a really shoddy poll to address what you said in the first para about hi res sounding better than redbook to people on here . https://www.audiosciencereview.com/forum/index.php?threads/poll-hi-res-music.22637/page-2 Early days but looks like the majority of responders say they cant discern a difference.

I have bought HD Audio files and can listen to them via QOBUZ but don't really know if they sound better or not.
I've taken the attitude that I want lossless and might as well play the best they have got.

That does not mean that HD-Audio cannot be just as awful as SD-Audio.
AdeleSkyFallDetails.jpg
AdeleSkyFallAudacity.jpg


This 96/24 track sounds as bad as it looks.
One can only imagine what additional splendor MQA can add processing these clipped "squarish" waveforms.

- Rich
 
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bidn

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So if I, as an artist, decide to include a test tone in my song, or something similar to a test tone for a specific effect, MQA will decide it isn't music and barf all over the track. How is that h-fi? How is that the "original true to source as intended by the artist" ?

LightninBoy, this is an excellent point about MQA's claims of removing the noise and keeping only the music.
This is the more so that there are musical genres where noise is sought for and is even fundamental!

I will be showing with some factual references to albums that in such genres noise is music,
so this is entirely for proving that MQA's claim about separating noise and music does not make sense,
so it is entirely relevant to MQA and to the effect MQA would to the audio tracks it transforms,
so please do not erase this post because it deals also with music
(and trying out music relevant to the topic may calm the moods?)

Below a few examples of genres where noise is not only inherent, but even absolutely essential to the music:
Warning: most people find this ugly sounding.

1. Noise experimental music
Within experimental (avant-garde) music, there is a whole sub-genre based on noise.
The most Seminal is Lou Reed's Metal Machine Music from 1975,
it is plenty of noise , incl. HF.... , where the noise is used to create musical patterns


2. Noise industrial electronic music

There are many famous bands in this genre (Cabaret Voltaire, etc.)
Here a seminal album, Throbbing Gristle's 1977 debut album The Second Annual Report
Singing and so on is purposefully distorted with noise:

Here another example from a 2012 compilation "United States Bestial Forces " from various artists, more recent, Constrictions'song Transparent, the noise is prevalent (very loud, you may want to turn the volume down):


3. Ambient and atmospheric black metal

Not even speaking of the purposefully distorted manner of playing the electrical guitar in metal, within back metal there are whole subgenres where noisy effects are used to create a hazzy atmosphere, this was pioneered by Burzum in his album Filosofem, which gave birth to ambient black metal (which itself evolved later to give birth to atmospheric black metal)
Here that seminal album, Filosofem, 1996, if you listen you will hear many passages were the music is very noisy :

Metal is not much mainstream but super active,
here there would be more than 1500 bands of ambient black metal:
https://www.metal-archives.com/search?searchString=ambient+black&type=band_genre
and about 1900 bands of atmospheric black metal:
https://www.metal-archives.com/search?searchString=atmospheric+black&type=band_genre
= a lot of music to be erased by MQA?

4. Noise ambient music

I am not sure about the seminal works here, but here an example:
Thomas Köner's 1993 Permafrost
It is ambient music, so very calm, soothing, in the background, but still consisting of noise (you may need to turn the volume up) :


I could add more examples, and more genres, like drone ambient music (smoothing engine sounds),
but this would become too long...
and I would not want this post to be erased and all the work I put here to be lost...


Conclusion re. MQA

These examples show that a substantial amount of modern music is based on noise,
and that here the music can absolutely not be separated from the noise which is its very essence.
Therefore MQA's claim to separate music from noise is wrong-headed and the MQA format is based on a fundamentally flawed principle.
Now what would MQA do to theses examples if tested, what could we expect?
- if it did remove the noise it would remove the music...
- if it didn't remove the noise, then its claim about removing the noise would be false.
 
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Teroz

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Thanks to @mieswall i think this MQA fight is back at starting line. No one has won anything. Not MQA lovers and not the "anti MQA" side.

To me (from full MQA decoder) i like "most" of the MQAs from tidal more than CD/FLACs, well at least on my STAX set. Yeah i got Qobuz too but i prefer MQA, still.

On my cheaper sets?.. Who cares. Sounds all the same, even the poor MP3s.
 

TK750

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LightninBoy, this is an excellent point about MQA's claims of removing the noise and keeping only the music.
This is the more so that there are musical genres where noise is sought for and is even fundamental!

I will be showing with some factual references to albums that in such genres noise is music,
so this is entirely for proving that MQA's claim about separating noise and music does not make sense,
so it is entirely relevant to MQA and to the effect MQA would to the audio tracks it transforms,
so please do not erase this post because it deals also with music
(and trying out music relevant to the topic may calm the moods?)

Below a few examples of genres where noise is not only inherent, but even absolutely essential to the music:
Warning: most people find this ugly sounding.

1. Noise experimental music
Within experimental (avant-garde) music, there is a whole sub-genre based on noise.
The most Seminal is Lou Reed's Metal Machine Music from 1975,
it is plenty of noise , incl. HF.... , where the noise is used to create musical patterns


2. Noise industrial electronic music

There are many famous bands in this genre (Cabaret Voltaire, etc.)
Here a seminal album, Throbbing Gristle's 1977 debut album The Second Annual Report
Singing and so on is purposefully distorted with noise:

Here another example from a 2012 compilation "United States Bestial Forces " from various artists, more recent, Constrictions'song Transparent, the noise is prevalent:


3. Ambient and atmospheric black metal

Not even speaking of the purposefully distorted manner of playing the electrical guitar in metal, within back metal there are whole subgenres where noisy effects are used to create a hazzy atmosphere, this was pioneered by Burzum in his album Filosofem, which gave birth to ambient black metal (which itself evolved later to give birth to atmospheric black metal)
Here that seminal album, Filosofem, 1996, if you listen you will hear many passages were the music is very noisy :

Metal is not much mainstream but super active,
here there would be more than 1500 bands of ambient black metal:
https://www.metal-archives.com/search?searchString=ambient+black&type=band_genre
and about 1900 bands of atmospheric black metal:
https://www.metal-archives.com/search?searchString=atmospheric+black&type=band_genre
= a lot of music to be erased by MQA?

4. Noise ambient music

I am not sure about the seminal works here, but here an example:
Thomas Köner's 1993 Permafrost
It is ambient music, so very calm, soothing, in the background, but still consisting of noise :


I could add more examples, and more genres, like drone ambient music (smoothing engine sounds),
but this would become too long...
and I would not want this post to be erased and all the work I put here to be lost...


Conclusion re. MQA

These examples show that a substantial amount of modern music is based on noise,
and that here the music can absolutely not be separated from the noise which is its very essence.
Therefore MQA's claim to separate music from noise is wrong-headed and the MQA format is based on a fundamentally flawed principle.
Now what would MQA do to theses examples if tested, what could we expect?
- if it did remove the noise it would remove the music...
- if it didn't remove the noise, then its claim about removing the noise would be false.

I'm glad you fixed that typo, I didn't want to be the pedant that pointed it out but it was a fairly important one!
 
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