Authenticated, the "A" of MQA...


#1

[ I posted this on Stereophile’s recent Axpona video on MQA support, but have had no responses. ]

Based on what I’ve read (too much, I suppose), the provenance and authentication is based on “sign off” by either the artist, recording engineer or producer. This is the “thumbs up” that we are listening to the real McCoy, or at least that’s what is being delivered.

Is that really happening? Did they get the artist (engineer, producer) back in the studio to listen to the MQA encoded and decoded audio to certify that it was exactly what was on the master tape? Or did they set up someone with a rubber stamp? Even if closer to the former, do they compare the master tape with the MQA version to assure they are I-dentical? I’m just as skeptical about this as I am the other, more technical bits, but those have been explored to death, a fair amount of which is conjecture or based on flawed listening experiences. (This is no criticism of anyone that shares their honest opinion.)

How is the authentication part actually done?


#2

Oh, oh, oh!!! One more thing. (Or is it more than that…)

If the MQA version is supposed to be identical to the master recording, could they not perform a null test in analog and verify that? Or at least that it’s closer than any other available version, high-res or otherwise?

On the other hand, if MQA corrects (deblurs) based on flaws in the master source, that wouldn’t work, would it.

I’m looking at a rabbit hole.


#3

@christophervalle

I have wondered the same thing. I hope someone can point us in the right direction. . . I’d like to read more about this very topic.


#4

The ghost of Jim Morrison authenticated all The Doors albums. One knock for no, two knocks for authenticated.

It’s a good question, especially with the older jazz LPs. No one involved in the recordings is probably still alive. It is one more example that MQA is more about money, and taking control of the media.

If they just would have marketed as an upgrade for streaming, that would have been believable. I can see John Stuart petting a white cat, saying first we take over Warner, then the world [insert evil laugh].


#5

What’s being authenticated is that the file you are playing is the one published by the studio/artist/whoever. It has not been played back and re-digitised. It has not been upsampled from a lower resolution source to now be passed off as a “master tape”.

The idea is to prevent the sort of thing we saw from HDTracks and elsewhere, where you could be fooled into obtaining a big “high res” file that was no better – and sometimes worse – than the CD that’s been in circulation for many years.


#6

Dvorak - what is the provenance of your statements?

I guess my notion was that Authenticated meant your rig is fully decoding the MQA file as they intend it, not anything about the format of the file used to make it.


#7

My understanding is the authentication - that is, the blue light which alights when MQA i active - means only that you are listening to the file decoded as MQA intended. We have to take on faith the original recording from which the file was sourced is what MQA says it is.


#8

Actually I think it is just BS. it would be like my Dolby digital light on my receiver going on. It’s Dolby digital…yup…engage light. Same with MQA it’s an authentic MQA signal. Haha. Wow.


#9

I like it…BSQA ; )


#10

SPEBSQSA?


#11

Master Quality Authenticated. That’s what MQA stands for. How do you authenticate master quality? Using cryptographic digital signing techniques and embedding a signature into the audio data stream.

That’s why performing an MQA encode requires a security module – there are cryptographic secrets being used to generate the signature. It’s an asymmetric keypair, meaning that the decoder can use a public key to mathematically validate that the bits it is decoding were signed off by somebody who knows the corresponding private key (that somebody ultimately being MQA themselves). If the math checks out, the blue light can come on.

The consumer value of this authentication is to give the listener confidence that the bits they’re listening to are the actual bits which were put out by the studio/artist/whomever. The value to MQA and the music publishers is something quite different… they get a point of differentiation which they hope will drive more consumer dollars in their direction.

http://bobtalks.co.uk/blog/mqa-philosophy/mqa-authentication-and-quality/

http://www.mqa.co.uk/professional/for-content-providers – see the questions “How much will MQA cost to implement” and “Where does HSM sit in my environment”


#12

See also points 6 and 7 here:

http://www.audiostream.com/content/mqa-reviewed


#13

Michael Lavorgna included a quote from Bob Stuart in a piece on MQA. (Emphasis mine.)

“The MQA authentication ‘light’ indicates Provenance in the source for the file. The MQA display indicates that the unit is decoding and playing an MQA stream or file and denotes provenance that the sound is identical to that of the source material. MQA Studio indicates it is playing a file which has either been approved in the studio by the artist/producer or has been verified by the copyright owner.”

This implies that someone (artist/producer/copyright owner) has listened to the MQA encoded file and signed off that it is identical to the master recording, in whatever medium it exists.

Is that actually happening? Based on how much material has already been released and the cost/time/complexity (unlikeliness) of doing that, I am justifiably skeptical.

Also, if the master recording is digital and “flawed” by pre-ringing which MQA corrects, they cannot be identical.

Through all of this, I’m not suggesting that MQA is not a valuable or beneficial technology. I’m not currently in a position to judge that for myself, and have read many personal observations, both pro and con, that I hope are sincere. I have a PS Audio Directstream Junior DAC, which is soon to be upgraded through Bridge II firmware and operating system updates to fully unfold and decode MQA. No matter what I find and decide, the question I have about the authentication claim remains.


#14

This is what worries me:

the SOUND is identical to that of the source material…

So this can be relative: Joe and Jane have different ears physically; Joe might say the “sound” sounds the same (MQA and source material) and Jane might disagree. It’s not a bit-wise comparison.

I think I’ll just stay with Redbook and DSD. The DS Snr already does a fantastic job on these formats.


#15

I think people are really over thinking this. Master ‘quality’ <> master recording. ‘Approved’ by the artist in the studio … well you could say that artist approved what was in the studio for a cd release could you not? Verified by the copyright owner? ‘Yes those are my songs and that is what I recorded’. You can make no inference in that article in my opinion.


#16
timm said

I think people are really over thinking this. Master ‘quality’ <> master recording. ‘Approved’ by the artist in the studio … well you could say that artist approved what was in the studio for a cd release could you not? Verified by the copyright owner? ‘Yes those are my songs and that is what I recorded’. You can make no inference in that article in my opinion.


I think Bob Stuart’s quote was pretty specific about someone (artist/engineer/copyright holder) hearing and validating that the MQA version is identical to the master. If it’s as you state, then I would call the claim malarkey.

In 1989, Tom Petty says of Full Moon Fever, “Yes, the CD mastering is good enough.”

In 2017, MQA says, “Yep, it’s encoded…trust us.”


#17

“Copyright holder” is a big one. If, like Michael Jackson or his assigns (at one point anyway), I owned the Beatles catalog, I could say, “Yep, these are all good - they were good enough before, so please go ahead and make me more cash.”