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MQA is Vaporware


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"alias artifacts" ??

 

If you are interested in what is happening with MQA's compression methods, go back in this thread and look for the link (I think miska posted it) of the article which describes in detail what happens. The MQA process produces alias products (artifacts).

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I wouldn't call it aliasing - so not sure what you mean.

 

If you sample without bandwidth limiting you get aliasing. This is a basic fact. Part of the MQA process does this, for audio over 48Khz (96 Khz sample rate). Its covered in one of the patents. My understanding is that 95% of the aliasing is inaudible. Part of the MQA approach is that a tiny amount of aliasing is better than the using aggressive transient-smearing filters on the DAC.

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... And all albums are just reconverted from redbook, not recorded as MQA...

 

Reconverted from redbook sounds like starting from a 44.1/16 master. This makes no sense at all. Most of what we are hearing is a new studio master, I assume at 96/24, with different levels of final EQ and DRC, turned into a MQA fie and streamed to our DACs. I wouldn't call that a redbook conversion.

 

I guess what you mean is that the recordings were not done with MQA as part of the workflow originally?

 

As aways, the lack of clear info from Bob means that we are stabbing in the dark to understand the differences between MQA as part of the original workflow, and MQA added as a later step.

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... And all albums are just reconverted from redbook, not recorded as MQA...

 

No. Some may have started as Redbook, but most are derived from recent remasters at 88.2 / 96 / 176.4 / 192 / 352.8 / 384.

 

And there is no such thing as "recording as MQA". MQA is a final process, not something that happens during recording. So all MQA recordings will be conversions from the final PCM master, whatever that looks like and however many steps removed from the recording process itself.

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No. Some may have started as Redbook, but most are derived from recent remasters at 88.2 / 96 / 176.4 / 192 / 352.8 / 384.

 

And there is no such thing as "recording as MQA". MQA is a final process, not something that happens during recording. So all MQA recordings will be conversions from the final PCM master, whatever that looks like and however many steps removed from the recording process itself.

 

I recall Bob talking about two different processes, one where they would analyze the master to unpick the ADC artefacts, and another process where the ADC was part of the MQA workflow. Perhaps this second process does not exist yet?

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I recall Bob talking about two different processes, one where they would analyze the master to unpick the ADC artefacts, and another process where the ADC was part of the MQA workflow. Perhaps this second process does not exist yet?

 

Could very well be, and I overlooked it. Will be interesting to see how this plays out.

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I guess what you mean is that the recordings were not done with MQA as part of the workflow originally?

Yes.

Reconverted from redbook sounds like starting from a 44.1/16 master. This makes no sense at all. Most of what we are hearing is a new studio master, I assume at 96/24, with different levels of final EQ and DRC, turned into a MQA fie and streamed to our DACs. I wouldn't call that a redbook conversion.

 

How You can be sure about 96/24 master? There is only hope that master is in that quality, nobody can't confirm that, hand in the holy bible. And if someone plays with different levels of EQ and DRC, is that really the original master or result of someones playing?

The whole thing called MQA makes no sense at all. If we all can listen the original 96/24 or some other choosen format for mastering, why someone needs to play with that master, ask money for that and then offers only lossy copy of (maybe) 24Bit master - remember, MQA stays below 18Bit resolution in the end of day - whatever blue led say's.

Sorry, english is not my native language.

Fools and fanatics are always certain of themselves, but wiser people are full of doubts.

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And there is no such thing as "recording as MQA". MQA is a final process, not something that happens during recording. So all MQA recordings will be conversions from the final PCM master

 

The most important part of the MQA process is compensating for the encoding characteristics of the ADC used in the recording process rather than the playback DAC.

 

It is this process that is the source of MQA’s claim of their files being superior to the original master.

 

Not the reconverting.

Sorry, english is not my native language.

Fools and fanatics are always certain of themselves, but wiser people are full of doubts.

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The most important part of the MQA process is compensating for the encoding characteristics of the ADC used in the recording process rather than the playback DAC.

 

It is this process that is the source of MQA’s claim of their files being superior to the original master.

 

Not the reconverting.

Agreed. But there are no recordings currently available that were made *at the time* with MQA in mind. So all of them are "conversions" of the final master with knowledge (or a guess) as to the ADC that was in use in the original recording - that's all I'm saying.

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Yes.

 

 

How You can be sure about 96/24 master? There is only hope that master is in that quality, nobody can't confirm that, hand in the holy bible. And if someone plays with different levels of EQ and DRC, is that really the original master or result of someones playing?

The whole thing called MQA makes no sense at all. If we all can listen the original 96/24 or some other choosen format for mastering, why someone needs to play with that master, ask money for that and then offers only lossy copy of (maybe) 24Bit master - remember, MQA stays below 18Bit resolution in the end of day - whatever blue led say's.

 

I said "assume" because neither Tidal nor my DAC reports the resolution of an audio stream, so I actually have no idea what the sample rate is. However the entire point of MQA is that whatever resolution is the master is, be it 44.1, 48, 88.2, 96, or 192 (or higher), that is what they deliver, packed into a 44.1 or 48 Khz container. So if the MQA track decodes to plain old 44.1 (and there is at least one album that does) then we know the master was a plain old redbook file. Users with DACs that report sample rates have posted various different sample rates for the MASTER files, indicating the various master sample rates.

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Samplerate is only one thing.

Think - MQA discards 20/24 bits down to 17bits before encoding anything! Even if original master is some 108Bit/100MHz hypotetical format. 17Bits are just a very little more than redbook CD, and noise is stronger after 14kHz in hearing range.

My current system can play every format as 32bit/384kHz - even if source file is 8bit/16kHz so if someone wants to fool listeners, it is very easy task to show what numbers you like, looks nice but sounds like ****.

In reality MQA cut's down bits and separates useful signal range to HF and LF part, where LF part carries useful compressed audio and HF part carries DRM codes and some higher audio signals if they are present. Priority is DRM, not higher audio signals because DRM is a must.

Sorry, english is not my native language.

Fools and fanatics are always certain of themselves, but wiser people are full of doubts.

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Samplerate is only one thing.

Think - MQA discards 20/24 bits down to 17bits before encoding anything! Even if original master is some 108Bit/100MHz hypotetical format. 17Bits are just a very little more than redbook CD, and noise is stronger after 14kHz in hearing range.

My current system can play every format as 32bit/384kHz - even if source file is 8bit/16kHz so if someone wants to fool listeners, it is very easy task to show what numbers you like, looks nice but sounds like ****.

In reality MQA cut's down bits and separates useful signal range to HF and LF part, where LF part carries useful compressed audio and HF part carries DRM codes and some higher audio signals if they are present. Priority is DRM, not higher audio signals because DRM is a must.

 

Bob Stuart has been at pains to refute the 17 bit allegation which comes from an old patent paper. In the stereophile Q&A he asserts that the apparent bit depth for 24 bit master is greater than 23 bits with MQA. Remember analog electronics max out around 20 bits.

 

My guess is that noise shaping and dithering make up for some or all of these missing bits.

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Bob Stuart has been at pains to refute the 17 bit allegation which comes from an old patent paper. In the stereophile Q&A he asserts that the apparent bit depth for 24 bit master is greater than 23 bits with MQA.

 

That's mathematically impossible. Don't trust anything that snake says.

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That's mathematically impossible. Don't trust anything that snake says.

 

Perhaps the key is in the phrase "*apparent* bit depth"?

 

 

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I guess you are flat out calling Bob a liar and that the above analysis is made up? I'm confused.

 

To paraphrase tweety bird "but I did, I did see a Big Fat Liar Bob Man".

 

I don't know enough about the mathematics of the bit depth thing to comment, but when it comes to DRM Bob is a Big....Fat....Liar.

Hey MQA, if it is not all $voodoo$, show us the math!

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MQA: Questions and Answers Sidebar 1: Example: Nielsen: 2L-120 Track 1 | Stereophile.com

 

I guess you are flat out calling Bob a liar and that the above analysis is made up? I'm confused.

I would strongly advise anyone 'throwing bits around' here and claiming MQA must be sounding really bad to read this article thoroughly first. MQA is not easy to understand from a technical PoV. But if you take the time it's certainly doable and there's a lot of very clever maths behind it. It's clear to me that a lot of technical allegations here are simply incorrect and based on lack of knowledge, which doesn't help the discussion.

W.r.t. DRM: I'm still not sure what to believe. But I will be using MQA mainly/purely with Tidal, so frankly I don't really care.

W.r.t. Bob: it's clear that he needs MQA badly, since Meridian has become a marginal company. So some sceptical remarks are valid. However, let's stick to the facts before criticizing.

 

 

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So, this MQA is social project to help out Bob Stuard from bad economical situation? Maybe...

 

Some clever math, applied to already "cleverly" computed PCM is better than DSD with minimal (fade-in, fade-out) or no intervention at all? Remember - all ADC is SDM (DSD) first, after that "clever" math of decimation begins...

 

We must ask what is important - lifelike audio or just EQ'ed and DRC'ed somehow, sometimes cleverly, sometimes not so cleverly computed audio, resembles interlaced "full-hd" video where picture is not actual HD, only half of that.

Sorry, english is not my native language.

Fools and fanatics are always certain of themselves, but wiser people are full of doubts.

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So, this MQA is social project to help out Bob Stuard from bad economical situation? Maybe...

 

I'm not in this world to help out Bob socially or financially, and neither are you I guess. [emoji6] Just stating a realistic PoV here. Meridian already lost Sooloos which was probably their biggest market asset.

 

Some clever math, applied to already "cleverly" computed PCM is better than DSD with minimal (fade-in, fade-out) or no intervention at all? Remember - all ADC is SDM (DSD) first, after that "clever" math of decimation begins...

 

Agree, I have some doubts here too and I also think DSD is an excellent and very natural sounding format. Not sure what MQA's 'correcting' impact in the ADC process exactly is..? Are you suggesting pure DSD wouldn't need any such correction? Just curious. What about inherent ADC jitter? I can tell you for sure that my Tascam DA-3000 sounds much better when using my external dCS wordclock connected to it when digitizing vinyl in native DSD. So DSD is also not immune to jitter, and neither is PCM. MQA claims to address jitter in the ADC as one of its key assets.

 

We must ask what is important - lifelike audio or just EQ'ed and DRC'ed somehow, sometimes cleverly, sometimes not so cleverly computed audio, resembles interlaced "full-hd" video where picture is not actual HD, only half of that.

 

This assumption is incorrect. When you read the several MQA articles on Stereophile properly there is no indication whatsoever for either EQ or DRC used in the MQA process. The 'origami' technique used by MQA means that less data is needed within a given bitrate than usual.

 

Let's be clear: I'm pretty sceptical towards MQA too, but I oppose to spreading personal opinions that don't reflect the actual situation.

 

 

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This assumption is incorrect. When you read the several MQA articles on Stereophile properly there is no indication whatsoever for either EQ or DRC used in the MQA process. The 'origami' technique used by MQA means that less data is needed within a given bitrate than usual.

 

Let's be clear: I'm pretty sceptical towards MQA too, but I oppose to spreading personal opinions that don't reflect the actual situation.

 

 

Sent from my HTC One_M8 using Computer Audiophile mobile app

Hi Maldur,

 

I just noticed that I mixed up your post with my comments. Sorry for that, and please notice my comments in my citation of your post too.

 

BR,

Vincent

 

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"EQ'ed and DRC'ed" applies to all PCM based formats, not only MQA, my question is broader than MQA. Fact is, Bob don't tell whole story about MQA and EQ. No matter where or who writes something about MQA, fact remains - some "clever" math is involved in process. Is this really nessesary? If basically every DAC is Sigma-Delta, I don't see much point.

Sorry, english is not my native language.

Fools and fanatics are always certain of themselves, but wiser people are full of doubts.

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