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Roon support of MQA

Thomas savage

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I'm always more than happy to be wrong so my mind is permanently 'open' on pretty much everything.

When it comes to subjective appraisal, well with the kind of biases flying around I think that's best left to WBF fitzcaraldo :D
 

Don Hills

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I have a mind like a steel trap. That sound you just heard was it clanging firmly shut. The bullock excreta starts with the very first sentence of that article and gets deeper and deeper. I'll just repeat what I say whenever this comes up:

"The time resolution of a 16 bit, 44.1khz PCM channel is not limited to the 22.7µs time difference between samples. The actual minimum time resolution is equivalent to 1/(2pi * quantization levels * sample rate). For 16/44.1, that is 1/(2pi * 65536 * 44100), which is about 55 picoseconds. To put that in perspective, light travels less than an inch in that time.

Shannon and Nyquist stated that as long as you keep all components of the input signal below half the sampling frequency, you can reconstruct the original signal perfectly - not just in terms of amplitude, but in terms of temporal relationships too. They only addressed sampling, and assumed infinite resolution in amplitude. With a digital signal the precision is limited by the number of amplitude steps, leading to the above formula."

If anyone wants to see this proven in real life, check out this video about the 20:55 mark.

 

watchnerd

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I had not seen this before, link below:

http://www.soundonsound.com/techniques/mqa-time-domain-accuracy-digital-audio-quality

In the unlikely event that there are others who, like me, still have an open mind. For those who have not already formed a definitive final judgement on the technology, whether heard or unheard, this is not a bad piece at all.

BTW, if people want to hear an apodizing filter, they don't need to use MQA -- they can listen to an iPhone or iPod, even older generation models.

As for me, I've listened to MQA multiple times via the Tidal desktop client. And I've also done ABX tests on myself of apodizing filters vs a well implemented linear phase filter and I cannot pass the test with statistical confidence on musical material.
 
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Werner

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But, it is also supposed to play music just fine with a non-MQA DAC. Stuart claims this sounds better than a non-MQA mastered version of the same file into the same DAC because the MQA file contains PCM signal which has been de-blurred, compensating for the original ADC. Please correct me if I am wrong.

You are wrong.

Assume an original 96k recording. If this is blurred at the ADC side (something I don't agree with, but let's assume for the moment...), then this blur lives at the ADC's anti-aliasing filter cut-off, i.e. 48kHz.

An MQA version of this recording
1) applies de-blur (at least, it claims to, but again I do not quite agree ...), which is signal processing around 48kHz.
2) folds the ultrasonic part of the signal (24kHz to 48kHz) down into the least signficant bits of the baseband (0-24kHz).

If you replay the baseband only, i.e. without MQA decoding, your player is not even remotely aware of the ADC's cut-off, since this is at 48kHz. The played only 'sees' up to 24kHz. So how can it profit from the ADC deblurring?

It can't. Simple.

There is more. In order to allow the folding/unfolding of item 2), there are two filters needed during production, and two other filters during decoding. These filters are inter-related, in that their task is to allow lossless folding/unfolding.
These filters insert their own blur, blur which will be net zero in a full encode/decode cycle. That blur will, however, not be zero in the case of an encode-only cycle.

DAC. If Tidal's software can do it, other software, codecs, etc. could easily follow.

As it stands now, it is not 'easy'. There are tons of gear out there that could do this decoding. Look at the LMS eco system, look at the various linux-based low-cost (but excellent, more than excellent!) streaming systems. These are based on open-source, free software. Look a the various DSP-based active speaker systems out there, commercial and DIY. If MQA have their way, these systems are locked out of it. Unless they pay.

If MQA were really serious about bringing better quality to the people, then they would open-source the decoder.
Since they do not do this, I can only conclude that their aim is to
1) make money in the short term, cynically
2) provide the music industry with a new cow and with a road to DRM.



And yes, I have listened to it. With tracks ripped out of Tidal, unfolded, into the main system (which is purely digital, room-corrected, and based around 96k only, hence MQA-incompatible, unless I ditch the entire caboodle), as well as with an Explorer2 into good headphones.

Quick findings:
1) some of the tracks on Tidal sound dire, regardless their format
2) in some cases the decoded MQA sounds identical to the existing hi-res downloads
3) in a few cases the MQA sounds better than alternative versions; but these are clear cases of better mastering: a bit of eq here, a tad of K-Stereo there, ...

3) shows that MQA can be an incentive to 'do better' (just as HDCD once did). 1) shows that many prefer not to follow this suggestion.
 
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ceedee

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Reading this thread made me want to clarify: are we accepting the premise that MQA sounds better than RBCD or 24/96 or 24/192? I haven't followed the MQA discussion in a while, so it's possible I missed some evidence that indicates listeners can actually tell a difference between MQA and existing lossless formats.

According to the Sound On Sound article posted earlier:
However, this exacting level of time-domain performance is only possible when MQA is employed as a complete end-to-end system, encompassing both the original A-D sampling and encoding within the mastering process, as well as the consumer access and decoding stages.

If "true" MQA requires new masters, it seems that it'll be unlikely for a true apples-to-apples comparison. Consumers and audiophile press usually compare file formats without making sure they have the exact same master anyway, even when it's very easy to do with free software on any computer. With hi-res PCM we can downsample to 16/44 and resample back to the native rate for a proper comparison; can the same be done with MQA?

Since a difference in mastering is likely orders of magnitude larger than the audibility of the "problems" that MQA purports to solve, it's pointless for anyone to make any comparison without being sure that the masters are identical.

And no, I don't feel the need to hear MQA first before being skeptical of it. When high-resolution formats were introduced to audiophiles, IMO the reasoning behind the promised improvement in SQ sounded even more logical and convincing than MQA, yet it turns out that under controlled conditions the differences are infinitesimal (if audible at all). It should be trivial for the people profiting off of MQA to back it up with listening tests; I'm always open to changing my mind.
 

Fitzcaraldo215

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I think you are exactly right. I do not think any controlled listening tests have been published. Controlled tests would certainly shift the focus of the discourse, because now the fora are largely filled with mere speculation about its theoretical or audible sound quality. And, of course, the high end press goes ga ga.

It is likely that such listening tests have been done internally by MQA and some licensees, however I do not think their publication would solve anything. People would remain just as skeptical or negative unless the tests were certifiably independent. But, who other than MQA or their licensees has the incentive to undertake such tests?

Also, I am not sure I agree that setting up, conducting and publishing controlled listening tests such that they are beyond reproach is trivial. I do not think it is, usually, even beyond the question of who is paying.

I share your skepticism, doubly. Beyond questions of sound quality, I question the commercial viability of this venture beyond a certain niche of Internet streamers. There are many incompatibilities with existing technology this new kid on the block must overcome.

Most of us really have no clue as to the magnitude (assumed > 0) of the sonic improvement this technology offers, if any.
 

Don Hills

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... I do not think any controlled listening tests have been published. ...

As far as I know, MQA have never compared the same track non-MQA vs MQA in any demonstration.
 

Fitzcaraldo215

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As far as I know, MQA have never compared the same track non-MQA vs MQA in any demonstration.
That has been a continuing criticism. Not sure if it has been addressed more recently. If not, it is only grounds for continued skepticism or negativity.
 

Kal Rubinson

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That has been a continuing criticism. Not sure if it has been addressed more recently. If not, it is only grounds for continued skepticism or negativity.
They sent me about two dozen paired files for comparison purposes. In addition, I have most of them already in my library.
 

Fitzcaraldo215

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They sent me about two dozen paired files for comparison purposes. In addition, I have most of them already in my library.
Thanks, Kal. Actually, I knew that comparisons like this were inevitable, and I am glad that this type of comparison will be part of your upcoming review with a certain, very sexy stack of equipment. I look forward to that.
 
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amirm

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They sent me about two dozen paired files for comparison purposes. In addition, I have most of them already in my library.
Ah. Did you publish/post any comparisons?
 

RayDunzl

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Werner

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They sent me about two dozen paired files for comparison purposes. In addition, I have most of them already in my library.

A large part of MQA's appeal to audiotypes is their claim that their process corrects for the sins of the recording ADC, be it at baserate (44k1) or higher.

What they should do, and easily could do, is to offer a set of short sound bytes with before/after comparisons of single instruments, so that everybody can hear that MQA is far superior. Outside of the unknowns of commercial music releases.

Because the sins of ADCs, if audible at all, will only manifest on some types of signal and only some of the time.
 

ceedee

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Also, I am not sure I agree that setting up, conducting and publishing controlled listening tests such that they are beyond reproach is trivial. I do not think it is, usually, even beyond the question of who is paying.
Quite right; "trivial" was a poor choice of words. I was just thinking that with all the scientific (sounding) language around descriptions of MQA, the white papers, patents, etc...surely these same people involved rigorous listening tests during the development of it, right? It shouldn't be that difficult to release their findings. Of course it would still be viewed with skepticism, but if the details were published, the tests could be repeated.

They sent me about two dozen paired files for comparison purposes. In addition, I have most of them already in my library.
That's a step in the right direction.

But...if there's no way for us to do the conversions ourselves, there will always be some question as to whether the MQA encoding was the only difference between the two files.

I'm very curious if they gave details as to how the comparison files are produced. The article said that the full benefit of MQA is only possible if it's a complete chain, from A/D to D/A. So does that mean two separate analog transfers would be involved?
 
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