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

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DimitryZ

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[edit: I have been making it sound like the decoder does this upsampling. Seems to make more sense to me that they would add the mirrored ultrasonics using the same technique but prior to or part of the encoding process. Then the decoder can treat these like other MQA files]

I'm pretty sure you are clear on this, but just so it is clear, this has nothing to do with the 2nd unfolding. The point made by @Werner is that when MQA files are made from 24/44 originals, the decoder (1st unfold) automatically upsamples with a weak filter to produce that mirroring. This gives the appearance of ultrasonics but since there were none to begin with I would call them fake.

Anyone can do the same. Here is what I get when I upsample a 44Khz version of the track using no filter (so worse than what MQA does):
View attachment 134088
Good Explanation, understood.
 

DimitryZ

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That's not the correct way of reading an FFT. The level of the ultrasonic images has to be integrated over the bandwidth they occupy, some 24kHz in this case. The result of that sum is what matters, and it will be substantial when compared to the payload signal, and easily within your system's capabilities, loudspeakers excepted.
I think that's the case if one wants to express it as a single number.

However, if one considers distortion as a function of frequency, the axes' labels for FFT and distortion vs. frequency are the same.

And the levels at -100dB will be below my system's noise floor, regardless of frequency.

What am I missing in above?
 

noobie1

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Some manufacturers are reporting the fees for MQA addition are substantial.
Roon and anyone else who markets an MQA software decoder ("first unfold") in their software apparently plays a licensing fee per MQA track played back.

I could see the first part being true for hardware manufacturers as they don’t have as much leverage as Tidal or record labels. Although it depends on what you define as substantial.

Second part sounds iffy especially the per track fees. That would create unlimited risk for software companies like Roon and Audirvana since they don’t charge their customers per track. I’ve been playing MQA tracks non-stop since this thread started. Audirvana hasnt throttled my MQA access.
 

Jim Austin

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@amirm, the pdf is posted in violation of Stereophile's copyright. I trust you'll remove it promptly.

Jim Austin, Editor
Stereophile
 
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PierreV

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Jim Austin

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It is my right but I neither like or dislike MQA. It is there once in a while when I search for music and it lands on an MQA title. I play it, it makes music and that is that.

What gets me to post is all the ill-informed stuff I read about it from people who don't know the topic. Stop doing that and I will go do something else. I just showed you again all the wrong things you say about this situation. If you don't like what I am doing, don't keep posting superficial talking points against MQA.

And who cares if you see or don't see benefit. It is a solution for a subset of high-res consuming people who want to use this format. The world of audio has far more serious problems that needs our attention but a few of you can't let this vendetta go. It has become personal for you causing you to lose objectivity.

Precisely the sentiment that inspired me to write that AWSI. I appreciate your thoughts on the subject. But please do take down the posted pdf. It will be posted soon enough on the Stereophile website, then people can link to it.

Best Wishes,

Jim Austin, Editor
Stereophile
 

RichB

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Here is the quote for the Roon COO:
You misunderstood then. It was not sarcastic. It’s absolutely a real and workable suggestion. If you don’t use Core Decodes, we don’t get billed.

Just don’t use the feature and we’ll stop getting billed and your money won’t go to MQA. That may not be obvious to anyone, which is why I suggested it.

Also, I can say this about our situation, but I want to make it clear that I can not say this about anyone else with any confidence as I don’t know their billing model.

Roon defaults to the MQA enabled so they may want to default it off.
Roon_MQA_Setup.jpg


- Rich
 
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DimitryZ

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That in the same FFT your system's noise floor will also be far below -100dB. Apples and apples.

But no, you won't hear it, as it is inaudible (at least directly so). But these spectral components do not belong there.
So this should be converted to absolute scale? DBFS? And if the recording is reasonably well equalized, wouldn't it already be the case or nearly so?

My Emotiva amps have something like -80dB distortion and something like -100dB noise. Seems like the aliased image at -100dB is too low in volume to be audible.
 

amirm

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@amirm, the pdf is posted in violation of Stereophile's copyright. I trust you'll remove it promptly.

Jim Austin, Editor
Stereophile
I couldn't find a "pdf" but I assumed you were referencing the jpeg scan of Jim Austin's article. I removed it. My apology for not catching it earlier.
 

amirm

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After a period of this thread moving along with no reports, we are back to conduct that has generated a number. I am not going to allow you all to create this kind of work and burden for our management team again.

I will leave this thread open for the rest of the day (my time) and then it will be closed. OP's video has been addressed in every which way. If you want to continue to discuss MQA, you can but be on warning that if it generates reports, it will be at your feet for restarting it.
 

amirm

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Some manufacturers are reporting the fees for MQA addition are substantial.
And you know of the correctness of that statement how? You don't think manufacturers who complain about such things could have another motivation to say that?

For my part, I have asked one company was being charged high fees and the answer was that the terms are confidential but that the fees are not a big deal.

Roon and anyone else who markets an MQA software decoder ("first unfold") in their software apparently plays a licensing fee per MQA track played back.
What a load of nonsense. Per-track fee? There is not one codec that has such a license fee. Having such fee would discourage playback of MQA content which is the opposite of the interest of MQA. And would require for the player manufacturer to report your playback history to the MQA which would be a total non-start from privacy point of view.

You and whoever cooked up this are confused by what Roon has said. While not common, you can license codecs and put them in your device but only pay its royalty for shipping it, if it gets used. When Sony licensed our WMA codec at Microsoft for Playstation, that is how the deal was structured. That way they did not pay for the codec for anyone who needed it. This tends to raise the royalty though but some licensors find it a useful mechanism.

This is what Roon has said: https://community.roonlabs.com/t/why-do-manufacturers-support-mqa/155965/21

"Sometimes the money leads to a dead end. We pay MQA to let you “Core Decode” in Roon. We don’t make money directly on MQA, we lose it! However, we do gain customer satisfaction for those who wanted MQA, which is in itself a form of being paid."

Core decode doesn't mean per track licensing. It is for the right for you to "core decode" MQA content. And they do it as cost of business to "gain customer satisfaction."
 

direstraitsfan98

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OP's video has been addressed in every which way.

So? Might as well close every thread in this forum by that logic. This thread has been a constant source of information and learning and it’s dismissive and arrogant to sweep all the effort some people have made under the rug.
 

amirm

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It isn’t an accusation and it’s totally called for. Stop deleting posts.
So you would feel good about people making accusations about you? We should leave those as well?
 
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