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

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Taddpole

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Anyway, it looks like MQA is in a precarious position if Tidal decide for some reason to pull the pin and I see no longevity in that from a commercial perspective.

I think Tidal's own longevity is questionable now the big players have entered the hi res game. Tidal pulling plug on mqa might be moot point.
 

KSTR

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Yes, full unfolds are only allowed to be performed by analog out only devices.
Bummer. Time to tap the I²S output of an XMOS receiver in a MQA DAC with an RPi or something, like @JohnYang1997 suggested.
 

UliBru

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Does this mean the number of (PC-)software full unfolders is zero? That'd really be dissapointing. So tapping the output of a firmware MQA final renderer chip like some XMOS is the only way?
Klaus,

Roon allows to define the setting of the audio device
1. no MQA support
2. decoder and renderer
3. decoder only
4. renderer only

In case 2 and 3 no decoding is done, the MQA stream is simply sent to the DAC for MQA processing. DSP e.g. samplerate conversion is not working as the stream gets directly sent to the DAC.

In case 1 and 4 Roon starts a decoder with samplerates 88.2/96, furthermore Roon says:
While the stream is playable on any DAC, MQA DAC's can perform further unfolding using this information.

So Roon clearly does not a apply a full MQA unfolding.
 

Raindog123

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Does this mean the number of (PC-)software full unfolders is zero? That'd really be dissapointing. So tapping the output of a firmware MQA final renderer chip like some XMOS is the only way?


Only if you believe there is any utility in that MQA firmware - beyond what any up-sampling process - DAC or DSP - with a filter of your preference would give you, that is... We are undoubtedly through the looking glass here.
 

Jimbob54

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Does this mean the number of (PC-)software full unfolders is zero? That'd really be dissapointing. So tapping the output of a firmware MQA final renderer chip like some XMOS is the only way?
Is my limited understanding. If you have twice folded content (so 176/192 or above) you HAVE to have a hardware solution as it currently stands to unfold all the way.

Now, I don't know how much mqa content on Tidal fits that, but there is some, it's not that rare. But yes, it's another legitimate query about the purpose of mqa. I know for sure all my dacs can play 192 PCM. Not so for mqa.
 

Raindog123

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Has @mansr really been banned from replying to this thread ? If so, that’s extremely disappointing, given his long history of work to demystify MQA...


"Pete," said Alley Oop, "it is a matter of some large distinction to be heaved out of this joint. You ain't arrived socially until you've been thrown out of here." (Clifford D. Simak, The Goblin Reservation, 1968)
 

DimitryZ

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There are lots of unknowns. Without further testing, breaking and reverse engineering, it is simply not possible to make independent software, that bit perfect can encode and decode MQA.
What?

It's certainly possible, provided such consumer can read.
 

adamd

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Only if you believe there is any utility in that MQA firmware - beyond what any up-sampling process - DAC or DSP - with a filter of your preference would give you, that is... We are undoubtedly through the looking glass here.
Whilst I have some sympathy for that position, nevertheless
1) end to end impulse response was one of the heavily touted features of MQA
2) in the frequency domain the triangle of music is supposed to include at least potentially stuff over 48kHz
3) IIRC some of the early promotional material suggested that there was soemthing like a second unfold (I seem to remember
a diagram with a zone C in the buried data), although I am aware that many people have asserted that the rendering is just upsampling (and even here there is the possibility of encoding through what Jim lesurf has called the leaky decimation filter)

....so on any basis it does not appear to be possible to analyse MQA as it claims to be without looking at the second unfold or rendering stage. The idea that MQA was just a clever way of packing 24/96 seems to be something of a novelty.
.
 

Dennis_FL

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I noticed the editors put a serious disclaimer on the MQA article

Editor's Note: Most of Bob Stuart's answers have been debunked and the MQA technology is now seen as lacking any benefit for anyone other than record labels and MQA Ltd.

I’m going to switch from Tidal. Amazon and Apple are streaming lossless to my DAC for free.
 
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DimitryZ

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Why be so rude? No point was missed—if you overstated, fine, but don't tell me what I need to do. You said, in reply to me, that all music fits the same "statistical envleope". Clearly, this is not true unless the envelope is absurdly broad. Any "high fidelity" encoder should allow signals that aren't your expectation of a "statistical" musical envelope.

I gave an example of unexpected music, not white noise, it was merely a related comment that we shouldn't have too narrow a view of what qualifies as music. I don't need to check with MQA, it wasn't about MQA, it was about Amir's comment of suitable source material in testing. White noise and square waves should absolutely be expected in audio that would end up in a streaming service. Music or otherwise—Apple Music has plenty of sleepy-time noise tracks. The solo in Lucky Man is unfiltered square waves (Emerson just got his modular, hadn't yet learned the joys of filtering—sure, it's a chorus of square wave oscillators, plus drums, but I'm sure I could fine you plain square waves in Kraftwerk or somewhere else, white noise bursts too). I think Amir might have meant their use beyond listening tests, as I allowed in my comment to him.
I have already posted that the test track should include test signals.
 

tmtomh

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Sorry, but this sort of thing is just not helping me. The premise of my post is that I cannot find the answer.
edit
I don't know whether that was a reference to this post-
https://www.audiosciencereview.com/...-tidal-to-test-mqa.22549/page-127#post-798595
I can see that that might in a sense answer my first question. But definitely not the others. Even then I'm afraid I'm lost as to what if anything is thought to be known. I'm confused by the file size comparisons and references to "16 bit" and all sort of things.

Don't blame yourself. The answers are difficult to find in such a huge thread, scattered over multiple comments - and while some of the answers are indeed there, some other of the alleged answers are not answers at all, but rather merely restatements of MQA's claims, which have not necessarily been verified. (This is NOT to accuse anyone of parroting MQA marketing - I'm just saying that by my reading some of the claimed answers are not actually definitive answers.)
 
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Raindog123

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if you have twice folded content


If I were you, I would run and quickly use some Listerine. Would this - packing both second AND third 'folded' bands (in the sense the word 'fold' implies) in those few bits of the 22kHz (44ksps) baseband - be even remotely possible, the guys would be gazillionaires by now! Selling their 'magical bottomless information bit inflators' left-and-right. :) Forget this boutique audio, the 5G industry would drown them in cash!
 
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tmtomh

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Why be so rude? No point was missed—if you overstated, fine, but don't tell me what I need to do. You said, in reply to me, that all music fits the same "statistical envleope". Clearly, this is not true unless the envelope is absurdly broad. Any "high fidelity" encoder should allow signals that aren't your expectation of a "statistical" musical envelope.

I gave an example of unexpected music, not white noise, it was merely a related comment that we shouldn't have too narrow a view of what qualifies as music. I don't need to check with MQA, it wasn't about MQA, it was about Amir's comment of suitable source material in testing. White noise and square waves should absolutely be expected in audio that would end up in a streaming service. Music or otherwise—Apple Music has plenty of sleepy-time noise tracks. The solo in Lucky Man is unfiltered square waves (Emerson just got his modular, hadn't yet learned the joys of filtering—sure, it's a chorus of square wave oscillators, plus drums, but I'm sure I could fine you plain square waves in Kraftwerk or somewhere else, white noise bursts too). I think Amir might have meant their use beyond listening tests, as I allowed in my comment to him.

He's not being rude exactly. Rather, he's employing one of several rhetorical devices he's routinely employed in this thread - and that he employed at the pinkfishmedia.net forums ("MQA pt ii" thread).

I'd suggest you not spend the time and effort to offer him evidence of your own understanding, or otherwise directly engage further with his comments, unless or until he demonstrates he has the level of understanding that he accuses you of lacking.

Also, keep in mind that as of the time of this comment, he's been a member here for less than 4 days and has racked up 124 comments, all only in this thread.
 

JSmith

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It's certainly possible
I'd imagine so...

That aside though, MQA encoder requires very specific settings... this is one reason why what was done and submitted to the automated MQA encoder produced the results it did.



JSmith
 

Thomas savage

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I'm starting to think those pictures of Amirim in a French maids outfit doing household chores do exist and Bob Stewart has a copy ..

It would be great to get back to audio research and objectivity that serves audiophiles needs of getting better sound , not getting ripped off while putting pressure on the industry to up standards . Have a laugh and not take online life to serious and maybe help each other learn and progress though shared understanding and principles..,

You know , like we used to do ..
 

Jimbob54

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If I were you, I would run and quickly use some Listerine. Would this - packing both second AND third 'folded' bands (in the sense the word 'fold' implies) in those few bits of the 22kHz (44ksps) baseband - be even remotely possible, the guys would be gazillionaires by now! Selling their 'magical bottomless information bit inflators' left-and-right. :)
Magic music origami, innit.
 

DimitryZ

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He's not being rude exactly. Rather, he's employing one of several rhetorical devices he's routinely employed in this thread - and that he employed at the pinkfishmedia.net forums ("MQA pt ii" thread).

I'd suggest you not spend the time and effort to offer him evidence of your own understanding, or otherwise directly engage further with his comments, unless or until he demonstrates he has the level of understanding that he accuses you of lacking.

Also, keep in mind that as of the time of this comment, he's been a member here for less than 4 days and has racked up 124 comments, all only in this thread.
No worries, I can do better, since I have been banned from PFM!

I attempted to argue there against mansr's scruroulous accusations that this forum's owner is paid by MQA. He accused me of the same, of course.

With my departure, PFM is totally anti-MQA safe space!
 
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