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

[Raindog123]

…another MQA ‘marketing point’ - tied to their newfound “better than lossless” - is that the FIR filters in the encoder can compensate for certain nonlinearities and distortions of ‘the entire data pipeline - from analog input to analog output”…

But if you scratch the shiny marketing surface, they are no different from any other end-to-end data path. There is no rule that a [some transfer function] compensating digital filter must be at the encoder only. In fact, if you want to compensate for some effects of the channel (‘data path’), there can be multiple filters: at the source (by encoder), at destination (by decoder or dac), and anywhere in-between (eg, your room compensation filter)…

With that, using a ‘traditional’ PCM stream, the recording-mastering-production process can release a data file that - through source DSP/filtering - compensates for all known studio imperfections and makes the sound “as the artist intended“ at that point (we can even call it “deblurring”, or anything we wish actually)… This data can now get delivered (streamed or file-transferred) to its destination in a lossless way - and lossless here is [bit-]perfectly, mathematically defined, no marketing wiggling.

At the destination, if needed the data can be modified yet one more time - eg, by convolving with a FIR now compensating for known imperfections of the destination environment (dac, amplifier, room acoustics). This FIR is synthesized locally - as ‘this destination‘s imperfections‘ are unique to one’s particular rack/room - and no MQA‘s at-the-source-processing can possibly predict every room/dac/amp specifics! (But again, those can be measured locally.) And by applying these [now destination] compensating filters, this is how one would truly get as close to “artist’s intention” as possible… (Goes without saying that MQA not only does not assist with this destination-compensation step, but rather directly stands in its way - by restricting access to digital signal processing/EQ’ing, discussed here multiple times.)

 

[DimitryZ]

That's a good text.

Does help, but doesn't solve the problem. The genre convention for Reddit tends to be short explanations, which get in the way of even summarizing more involved arguments like that. So still makes it difficult.

And for every person seeking help on Reddit (or even here at ASR), there's gotta be another 10 to 100 who just go with MQA because of that misinformation. Or go with it because a friend, who fell for the advertising, told them it's great.

They might be choosing Tidal because of the misleading MQA marketing which makes them think it has the best SQ, where they actually like the catalog or user experience of Amazon HD or Quboz better. Or maybe they bought a Dragonfly to get MQA when they could have saved money or have gotten a better DAC for their money.

Consequently, what's needed is more people speaking up about the misleading advertising prose to help counter that misinformation, as well as to counter those who want to silence criticism of MQA.

It's interesting to know this. On audiophile forums, generally MQA gets no love.

So warning the unsuspecting crowd that MQA advertising is overly aggressive and boastful seems like good advice.

At the end of the day people will make up their mind and will either like it or switch to Qobuz, and now Amazon or Apple

 

[DimitryZ]

Thank you - I appreciate that.


This statement reflects a fundamental error in the application of digital sampling theory, and/or a series of unsupported (and I would say disproven) beliefs about the capabilities of modern reconstruction filters.

CD/redbook's 44.1k sampling frequency can encode frequencies up to and slightly beyond the range of human hearing. In terms of accurately sampling audible musical sounds, doubling the sample rate to 88.2k gets you nothing. If sampling any frequency more than the 2 times necessary for proper reconstruction provided an increase in audible "resolution" (as the term is often misused in audiophile circles), then we'd all be in a lot of trouble: No matter the sample rate you use, a bass drum at 60Hz is sampled 30-85 times more than a musical sound in the 2-5kHz range where human hearing is most sensitive, and therefore by the "more sampling = higher resolution" fallacy, lower frequencies of music would always be more refined and hi-fi than higher ones (which is of course not true). Once we reach the minimum 2 samples per frequency, the number of additional times we sample is irrelevant - and it's a good thing because different frequencies get oversampled by vastly different degrees, no matter the sample rate.

Now, if your point is that 88.2kHz is better because it allows for a gentler-sloping reconstruction filter between 20kHz and Nyquist than CD/redbook does, the problem there is that one can find plenty of data all over these forums, primarily in @amirm 's reviews of DACs, that illustrate the ability of relatively steep filters to function properly in the 2.05kHz space that redbook provides. Conversely, he's shown measurements of many pieces of equipment that use filters that have such poor out-of-band attenuation that even an 88.2k sample rate won't save you - and in fact it can be worse because there could be more ultrasonics in the file, which leads to more aliasing into the audible band. So yes, in an ideal world we'd have more consistency in filter quality, and in an ideal world the physical size and scan rate of the video tape format Sony first used for PCM encoding would've allowed for a 48 or 50kHz sample rate instead of 44.1k. And on filters it's worth noting that Bob Stuart is a major reason so many slow filters and "apodizing" filters are out there to begin with, as he's been evangelizing them for decades based on provably incorrect claims and assumptions.

Bottom line, MQA's sample rate is not a "starting advantage" over redbook.


You stand by the DXD comparison - except when it doesn't suit you, as for example when you instead compare MQA with CD/redbook, as you did earlier in the very same comment.

Your claim that DXD "is the modern lossless master from which all consumer distributions originate CD" (italics mine), is false. Putting that aside,
it has already been explained, quite clearly and in detail, why the fact that a CD is downsampled from a higher-res digital master has nothing whatsoever to do with the question of whether it makes sense to compare MQA with DXD. The responsibility for not acknowledging the relevant points or taking them into account lies with you.


By my last paragraph, do you mean the final bullet point where I point out that you praise MQA's discarding of some ultrasonics while not acknowledging that in order to keep the remaining ultrasonics it has to compromise bit-depth? I'm not sure what to say in terms of understanding, since I think my point there is fairly clear. Sorry if it's not. I had no specific intention to insult you; rather, I tried to be as specific as I could, just as I did in the other two bullet points, about exactly what aspect of your prior comment I took issue with, precisely why, and how it landed to me as a reader.

If instead you're referring to the final bit of my comment, about your acknowledgement of MQA oversampling as "kind of fakey," I was agreeing with you there and had no critical intent.

More generally, I will modulate my language whenever necessary to conform to forum rules and mod requests. Beyond that, though, when it comes to critical comments about your mode of argument here, I'm afraid you've made your own bed.

In your first section, you are seemingly arguing against hires in general. If you take that position, we don't need any hires format for consumer distribution and the conversation is over. Audiophile consumer seems to want hires formats, hence Amazon and now Apple entering the field (without MQA).

In your second section you disagree that DXD is a modern hires master format. I do see these files offered on sale as "masters" and I read others describe them in these terms. I am sure there are competing mastering formats, but DXD does seem popular. And if one starts with DXD or another very high resolution format and produces a consumer distribution at CD resolution, MQA format or a medium resolution LPCM, all of these choices can and should be comparable to each other and to the originating master. To me that's a very rational position.

In your last section you make a fair point that MQA compromises bit depth for their ultrasonic content. That's definitely the case and also reduces the standard playback at least for some people on some material. I reported this detriment over two years ago on PFM.

I will be polite as well.

 

[John Atkinson]

Do they simply erase the lower bits entirely? Or they add the mqa information packed as as pseudo noise to the lower bits? This last one seems pretty far fetch, especially regarding how to recover this packed data among the noise at decode time, but I prefer to ask anyway, we never know maybe this codec is very clever.

See my explanation with one of my own 2Fs recordings how audio information with frequencies higher than half the the 1Fs sample rate can be packed into the low bits of a 24-bit file sampled at 1Fs without compromising the recording's analog noise floor:
https://www.audiosciencereview.com/...-music-on-tidal-to-test-mqa.22549/post-759747
and
https://www.audiosciencereview.com/...-music-on-tidal-to-test-mqa.22549/post-760938

This is a technique called "steganography" - see https://www.researchgate.net/publication/45949372_Steganography-The_Art_of_Hiding_Data

John Atkinson
Technical Editor, Stereophile

 

[pjug]

In your first section, you are seemingly arguing against hires in general. If you take that position, we don't need any hires format for consumer distribution and the conversation is over.

Maybe the technical discussion is over then. But the problem is this may be not be an option because MQA seems to want to force ultrasonics onto us, and take redbook away in favor of MQA-CD (most of which have only fake ultrasonics).

Edit: the MQA-CD really bugs me. If not for that, the Tidal tiering with cd quality and another for MQA would make sense, and customers could happily subscribe to redbook if they want. And now we have to watch out for MQA-CD sneaking into other services as well.

 

[Daverich4]

The problem I have with the CD explanation is that MQA was launched in 2014 and the format has exclusively been used for streaming.

Not exclusively. Mainly might be a better term as a search of Amazon shows more than 300 MQA albums for sale and there are a number of other sources for them as well.

https://www.amazon.com/s?k=mqa+cd&crid=2DDR9PZM2FKDP&sprefix=Mqa,aps,549&ref=nb_sb_ss_ts-doa-p_3_3

 

[DimitryZ]

See my explanation with one of my own 2Fs recordings how audio information with frequencies higher than half the the 1Fs sample rate can be packed into the low bits of a 24-bit file sampled at 1Fs without compromising the recording's analog noise floor:
https://www.audiosciencereview.com/...-music-on-tidal-to-test-mqa.22549/post-759747
and
https://www.audiosciencereview.com/...-music-on-tidal-to-test-mqa.22549/post-760938

This is a technique called "steganography" - see https://www.researchgate.net/publication/45949372_Steganography-The_Art_of_Hiding_Data

John Atkinson
Technical Editor, Stereophile

Thank you, @John Atkinson , very informative.

 

[Raindog123]

…In regard to “the hi-res demanded by the market”… I think the market, the consumer demand here is constantly being shaped, just like it always is: through (streaming) advertisement, by magazines, by discussions like ours…

I remember myself only a couple of years ago - craving every hi-res source I could only get my hands on… audio-DVDs, files for purchase, Tidal, Qobuz…

Yet today - while I still listen my music for 3-4 hours daily over decent speakers or cans (probably 90% Qobuz streams, the rest are CD rips) - I no longer care whether it’s a 24/48, 24/96 or occasional 24/192 (or even 16/44). Nor have any difference in the pleasure I get, whether you measure it in taps or stomps.

 

[DimitryZ]

Maybe the technical discussion is over then. But the problem is this may be not be an option because MQA seems to want to force ultrasonics onto us, and take redbook away in favor of MQA-CD (most of which have only fake ultrasonics).

It seems that the chances of that are really remote. I wanted to try MQA-CD, since I own one of the few affordable disc players that will decode them.

There is few of them and their are very expensive. Even I, who is essentially a format hoarder, got them as curio pieces.

 

[pjug]

It seems that the chances of that are really remote. I wanted to try MQA-CD, since I own one of the few affordable disc players that will decode them.

There is few of them and their are very expensive. Even I, who is essentially a format hoarder, got them as curio pieces.

They are on Tidal. I can post the list of Tidal MQA releases .csv again if you want to look at all the 16 bit ones. Also Tidal has two different names for these file types, though I can't remember their terminology [maybe "master" and "master studio", something like that]. So take note when you are listening on Tidal and I am sure you will come across some of them.

 

[oryan_dunn]

Yup, this is exactly the reason for a lot of the scepticism. I've said before that I am 100% convinced the pitch to Tidal and the labels (and anyone else they approach) is massively different than the spin to the end consumer. Trying too hard to be all things to all people.

The pitch to Tidal was probably all based on bandwidth cost savings for "lossless" high res audio.

MQA marketing it as lossless or "better than lossless", it's clear that in either case, they certainly can't mean a zip file for audio bits. With the traction this has, I think anyone who cares about this stuff now knows it's not lossless.

 

[Steve H]

In your first section, you are seemingly arguing against hires in general. If you take that position, we don't need any hires format for consumer distribution and the conversation is over. Audiophile consumer seems to want hires formats, hence Amazon and now Apple entering the field (without MQA).

In your second section you disagree that DXD is a modern hires master format. I do see these files offered on sale as "masters" and I read others describe them in these terms. I am sure there are competing mastering formats, but DXD does seem popular. And if one starts with DXD or another very high resolution format and produces a consumer distribution at CD resolution, MQA format or a medium resolution LPCM, all of these choices can and should be comparable to each other and to the originating master. To me that's a very rational position.

In your last section you make a fair point that MQA compromises bit depth for their ultrasonic content. That's definitely the case and also reduces the standard playback at least for some people on some material. I reported this detriment over two years ago on PFM.

I will be polite as well.

DimitryZ,

I have enjoyed your posts and would like to add a few comments. I wrote on January 2, 2017 I would not test MQA until eight of the nine reference albums I use to test audio were converted to MQA. (MQA is Vaportware) To my knowledge this has not happened, so I have not tested but I have listened MQA.

I listened to The Doors Riders on the Storm at T.H.E. Show 2016, both the MQA version and a non MQA version. There should be two rain sounds, one from the keyboard and one from the special effects soundtrack added. On the MQA version there is only one sound.

I am fan of Dr Dog so I am quite familiar with the album B-Room. The MQA version’s soundstage is thinner on the edges. Not a desirable trait in my opinion.

And I asked Richard Vandersteen at T.H.E. Show in 2019 to play the MQA and non MQA versions of Pet Sounds. The MQA version did not present the wall of sound properly.

My limited listening to MQA files has given me a lot to think about when I can test MQA music.

But there still is not a large selection of MQA on Tidal according to Duncan Rolfe’s spreadsheet posted May 19th on a private MQA Facebook group, MQA audio – developments and reviews. About 107,000 albums, most seen to be studio production files 24/44.1, very few could be considered high resolution.

Steve H

 

[DimitryZ]

They are on Tidal. I can post the list of Tidal MQA releases .csv again if you want to look at all the 16 bit ones. Also Tidal has two different names for these file types, though I can't remember their terminology [maybe "master" and "master studio", something like that]. So take note when you are listening on Tidal and I am sure you will come across some of them.

Maybe switch to other three options, all non-MQA?

 

[DimitryZ]

DimitryZ,

I have enjoyed your posts and would like to add a few comments. I wrote on January 2, 2017 I would not test MQA until eight of the nine reference albums I use to test audio were converted to MQA. (MQA is Vaportware) To my knowledge this has not happened, so I have not tested but I have listened MQA.

I listened to The Doors Riders on the Storm at T.H.E. Show 2016, both the MQA version and a non MQA version. There should be two rain sounds, one from the keyboard and one from the special effects soundtrack added. On the MQA version there is only one sound.

I am fan of Dr Dog so I am quite familiar with the album B-Room. The MQA version’s soundstage is thinner on the edges. Not a desirable trait in my opinion.

And I asked Richard Vandersteen at T.H.E. Show in 2019 to play the MQA and non MQA versions of Pet Sounds. The MQA version did not present the wall of sound properly.

My limited listening to MQA files has given me a lot to think about when I can test MQA music.

But there still is not a large selection of MQA on Tidal according to Duncan Rolfe’s spreadsheet posted May 19th on a private MQA Facebook group, MQA audio – developments and reviews. About 107,000 albums, most seen to be studio production files 24/44.1, very few could be considered high resolution.

Steve H

About half of audiophiles like MQA and half prefer LPCM. And you have three LPCM streaming choices now.

 

[pjug]

Maybe switch to other three options, all non-MQA?

You have a funny way of conversing. You said MQA is a rarity. When I try to show you that they are not you start talking about something else.

 

[amirm]

Once again I have to ponder why this encoded information is being stored in the audible band like it’s the 1970’s. You can put more than two tracks in a digital file!

They are showing how wasteful PCM is in that you can stuff all the extra spectrum in the baseband layer for distribution. It also gives backward compatibility with standard PCM playback which is always considered a major bonus (technically and otherwise). But yes, it did make their job much more difficult and the solution much more complex.

 

[DimitryZ]

You have a funny way of conversing. You said MQA is a rarity. When I try to show you that they are not you start talking about something else.

I don't see MQA taking over. I am trying to be positive (with encouragement from moderators ) - people who don't like MQA have lots of choices to avoid it.

I haven't checked myself, but @amirm posted here that MQA still remains a small fraction of Tidal content and is essentially infinitesimal on the world scale. I have no reason to disbelief him. On the jazz and blues genres it's less than 10%.

However, if you are concerned, you can easily avoid it now.

 

[amirm]

Do they simply erase the lower bits entirely? Or they add the mqa information packed as as pseudo noise to the lower bits? This last one seems pretty far fetch, especially regarding how to recover this packed data among the noise at decode time, but I prefer to ask anyway, we never know maybe this codec is very clever.

Your phone would not work without this technique! Spread spectrum is used to encode a signal among a ton of RF noise and then recovered. Correlated data is easy to distinguish from uncorrelated noise. Add some redundancy and you can recover pathological cases. What seems random to the eye is not random to cross-correlation algorithms.

 

[pjug]

I don't see MQA taking over. I am trying to be positive (with encouragement from moderators ) - people who don't like MQA have lots of choices to avoid it.

I haven't checked myself, but @amirm posted here that MQA still remains a small fraction of Tidal content and is essentially infinitesimal on the world scale. I have no reason to disbelief him. On the jazz and blues genres it's less than 10%.

However, if you are concerned, you can easily avoid it now.

Hereyou can find the list of MQA albums on tidal, which includes track count. So something like 1.5M tracks. Most of them are 16 bits. Sure to be expanding rapidly.

https://www.meridianunplugged.com/ubbthreads/ubbthreads.php?ubb=showflat&Number=268318

 

[Jimbob54]

Hereyou can find the list of MQA albums on tidal, which includes track count. So something like 1.5M tracks. Most of them are 16 bits. Sure to be expanding rapidly.

https://www.meridianunplugged.com/ubbthreads/ubbthreads.php?ubb=showflat&Number=268318

Yup- if you look at the new pop releases , a significant proportion are MQA in one form or another