Another major look at MQA by another pro.

[mevdinc]

Just read this article on Digital Audio Review shared by Srajen Ebaen of 6moons.
Very interesting to say the least.

http://www.digitalaudioreview.net/2017/07/kih-46-mqas-missing-link/

Best.
Mev

[PeterSt]

I don't need to read it to know this (the very article) has all been dealt with in CA, extensively.

 

Not sure what to think about it, actually.

[PeterSt]

My advice to Mr Ebaen is to stay objective. He is not that now. Not wise.

[mcgillroy]

17 minutes ago, PeterSt said:

My advice to Mr Ebaen is to stay objective. He is not that now. Not wise.

 

Explain objective dear compatriot. And don't you think that Ebaen might have seen more than one vendor having mailed him on MQA, the technical merits, the licensing issues and the general lack of dissenting voices?

 

If somebody like him comes out and goes against well funded and entrenched players he sure has some more backing.

 

It might be wise to hear this people out and force Bob and the lot to address the issues raised.

[semente]

4 hours ago, mevdinc said:

Just read this article on Digital Audio Review shared by Srajen Ebaen of 6moons.
Very interesting to say the least.

http://www.digitalaudioreview.net/2017/07/kih-46-mqas-missing-link/

Best.
Mev

 

By Pro you mean professional marketeer? 

[mevdinc]

2 hours ago, semente said:

 

By Pro you mean professional marketeer? 

I mean as someone in the business of making rather than just listening.
At the end of the day most topics discussed here involve hardware/software produced/marketed by people.

I don't know the music server guy, Srajen shared his email, and I thought what he said was interesting enough to share here. That's all.

[plissken]

7 hours ago, mevdinc said:

Just read this article on Digital Audio Review shared by Srajen Ebaen of 6moons.
Very interesting to say the least.

http://www.digitalaudioreview.net/2017/07/kih-46-mqas-missing-link/

Best.
Mev

 

I just saw 6 moons / Ebaen and immediately it goes to the ignore department.

[mansr]

2 hours ago, plissken said:

I just saw 6 moons / Ebaen and immediately it goes to the ignore department.

He's just publishing an email someone sent him in full.

[kumakuma]

14 minutes ago, mansr said:

He's just publishing an email someone sent him in full.

 

Even less work than rewriting a manufacturer's press release...

[mcgillroy]

34 minutes ago, kumakuma said:

 

Even less work than rewriting a manufacturer's press release...

 

Indeed - but have you read the mail?!

[kumakuma]

6 minutes ago, mcgillroy said:

 

Indeed - but have you read the mail?!

 

Isn't it the same as what was posted here?

 

https://www.computeraudiophile.com/forums/topic/33766-upsampling-mqa-files-to-original-resolution-with-sox-will-sound-like-the-original-resolution/

 

[mevdinc]

15 minutes ago, kumakuma said:

 

Isn't it the same as what was posted here?

 

https://www.computeraudiophile.com/forums/topic/33766-upsampling-mqa-files-to-original-resolution-with-sox-will-sound-like-the-original-resolution/

 

I hadn't seen this, sorry for the repeat.
I'd assume that Stjane hadn't seen the above discussion either,  he probably thought only he received this mail.

Anyway, Chris or I can always delete the post if it's causing confusion.
I don't know what would be the best practice.

[mcgillroy]

7 minutes ago, kumakuma said:

 

Isn't it the same as what was posted here?

 

https://www.computeraudiophile.com/forums/topic/33766-upsampling-mqa-files-to-original-resolution-with-sox-will-sound-like-the-original-resolution/

 

 

Yep - same observations about the possible filter-behavior of MQA.

 

Difference is a.) it's a vendor, who b.) put his proper name behind it, c.) agreed to have it published in a publication, d.) found an editor having the balls to do so.

 

The CA Forum has emerged as an epicenter of MQA-research but this debate needs more participants and especially needs to move beyond fora. With the technical details that Soxr, Mansr, Archimago and others have uncovered in the past weeks the debate is entering a new phase.

 

Firstly the audiophile website publishers will have to make up their mind how to deal with the presence of this information. Will they simply keep rewriting MQA press releases and lip-sync the big press, will they steer clear of the whole thing, or dare to engage in the debate?!

 

Secondly vendors now can speak more openly without feared being hit with a lawsuit for breaking NDAs. Yes Soxr was first with this but notice that two weeks later a vendor comes out and tells us that not only he has come to a similar insight, he also tells us that Aureliac obviously did too. Without having seen the MQA NDAs I am pretty certain this wouldn't have happened if Soxrs and Mansrs/Archimagos material on the filter-topologies wasn't public already.

 

So this post by Ebaen might indeed been less work than rewriting a press release. But its a sign of something shifting. It gives the increasingly solid research into the questionable merits of MQA more exposure and the more people talk and ask questions the better.

 

It will be interesting to see if, when & how MQA reacts.

[NOMBEDES]

Major point, which is not often expanded upon, is the claim that MQA screws up DSP.  If true, that is a big fly in the ointment.   DSP is the future.  MQA, maybe not so much?

[kumakuma]

21 minutes ago, mcgillroy said:

 

Yep - same observations about the possible filter-behavior of MQA.

 

Difference is a.) it's a vendor, who b.) put his proper name behind it, c.) agreed to have it published in a publication, d.) found an editor having the balls to do so.

 

The CA Forum has emerged as an epicenter of MQA-research but this debate needs more participants and especially needs to move beyond fora. With the technical details that Soxr, Mansr, Archimago and others have uncovered in the past weeks the debate is entering a new phase.

 

Firstly the audiophile website publishers will have to make up their mind how to deal with the presence of this information. Will they simply keep rewriting MQA press releases and lip-sync the big press, will they steer clear of the whole thing, or dare to engage in the debate?!

 

Secondly vendors now can speak more openly without feared being hit with a lawsuit for breaking NDAs. Yes Soxr was first with this but notice that two weeks later a vendor comes out and tells us that not only he has come to a similar insight, he also tells us that Aureliac obviously did too. Without having seen the MQA NDAs I am pretty certain this wouldn't have happened if Soxrs and Mansrs/Archimagos material on the filter-topologies wasn't public already.

 

So this post by Ebaen might indeed been less work than rewriting a press release. But its a sign of something shifting. It gives the increasingly solid research into the questionable merits of MQA more exposure and the more people talk and ask questions the better.

 

It will be interesting to see if, when & how MQA reacts.

 

My post was just a snide comment about lazy journalists. I'll remember the smiley next time.

 

P.S. I'm on your side. I think MQA is a major step back in audio technology.

[Shadders]

Hi,

I did read some of the interview with Bob Stuart on the CA website.

How does the analysis of the MQA system correlate with the answers provided by Bob Stuart ?.

Are there discrepancies ?

Regards,

Shadders.

[soxr]

2 hours ago, mcgillroy said:

Secondly vendors now can speak more openly without feared being hit with a lawsuit for breaking NDAs.

 

What we discovered was based on the assumption that Meridian would re-use their old tricks like in their cd-players. Measurements and hypothesis papers from xivero, archimago and Jim Lesurf lead to the idea of testing minimum phase. This started half a year ago.

The sox library has always been part of the DSP we use, but MQA motivated me to search &find better ways to use the library. It was on my todo list, but MQA just motivated me to work faster.
 

 

Quote

Yes Soxr was first with this but notice that two weeks later a vendor comes out and tells us that not only he has come to a similar insight, he also tells us that Aureliac obviously did too.

 

I analyzed the firmware that was sent as an update to my Auralic Mini. I managed to untar and dump the contents of "source.tar" via binwalk, found a compressed ramdisk, mounted this on one of my many linux systems. I was looking for MPD after some rumor that Auralic was using MPD, but after a discussion with their CEO I found lightningplayer linked libsox instead.

They use the libsox version, which can do both resampling and all the typical sox effects from the command line.  Libsox can also do room correction, parametric EQ and so much more.

I actually send a message here on the forum to Auralic to confirm my sox analysis. They confirmed. There's still an old MPD version but it's not started at boot.

So the good part is that more than one manufacturer has figured out how to find an alternative way to playback MQA. I decided to make the method open, so anywone can benefit from this. My method is not based on reverse engineering of the OSS libraries used by auralic, because sox was already in our own product since day 1 in 2013.

I dumped the firmware a few days ago. It just confirms sox can do the trick.
 

Quote

Without having seen the MQA NDAs I am pretty certain this wouldn't have happened if Soxrs and Mansrs/Archimagos material on the filter-topologies wasn't public already.

I did all my research based on what is published in public.Since archimago's / mansr's analysis on the renderer part of MQA, they basically 100% confirmed what I suspected. That was the smoking gun.  I decided to try soxr on MQA files, which led to my first post here on CA. I already was using soxr + minimum phase upsampling on redbook files with great result. It removes a layer in between the listener and speakers. This part is not confirmed by some of archimago's research, but I have access to a lot of cost is not object sets to test our idea's on.

So credits go to Mansr and Archimago but also Jim Lesurf and Xivero:
http://www.audiomisc.co.uk/

 

Jim did a lot of good work on the aliasing problem of MQA, and provided a similar entropy reduction scheme like Xivero. Putting all this info together was the reason for doing testing with minimum phase.

The smoking gun was the disclosure that the renderer part is just upsampling with their weird anti-ringing.
Without archimago and mansr's hacking of the output of the first unfold, this would still be guesswork.

It's time to deblur MQA.
 

 

[mcgillroy]

Thx soxr for setting the record straight! It's good to know where credit is due and have timeline of events. I follow MQA off and on and sometimes miss parts of the discussion.

 

Because of possible NDA repercussions I deliberately didn't infer in my post that you are the same person quoted in the Ebaen part

 

It's indeed time to deblur MQA. It would be great to have a similar report from you as Xivero published. Doesn't need to be 40+ pages but a more formal PDF putting together above's timeline and the main findings so far certainly would be helpful.

[Fitzcaraldo215]

2 hours ago, NOMBEDES said:

Major point, which is not often expanded upon, is the claim that MQA screws up DSP.  If true, that is a big fly in the ointment.   DSP is the future.  MQA, maybe not so much?

I agree.  This is the biggest issue that prevents me from considering MQA as anything other than a curiousity. 

[mansr]

3 hours ago, NOMBEDES said:

Major point, which is not often expanded upon, is the claim that MQA screws up DSP.  If true, that is a big fly in the ointment.   DSP is the future.  MQA, maybe not so much?

MQA certainly ruins DSP as it normally used today. Before any manipulation, the core decoder must do its job. Here there are two possibilities. The MQA decoder can be part of the DAC, which means the DSP must also be done there. This means we're looking at an AVR-like device incorporating both MQA decoder and DSP stage. Such a device can of course be quite capable, but forget about tinkering with HQPlayer or custom solutions. The other option is software decoding. This produces a 96/24 PCM stream to which DSP can be reasonably applied. Doing so will incapacitate any downstream renderer, but that's actually a good thing. The problem is that software decoders are rare as hen's teeth. Audirvana is the only general-purpose player with MQA support and it runs only on Macs. If you prefer another OS or player, you're out of luck. Others may of course appear with time, but there's no way a free, let alone open source, player will ever be officially licensed. This is not a path we should be taking.

[soxr]

8 hours ago, mansr said:

The other option is software decoding. This produces a 96/24 PCM stream to which DSP can be reasonably applied. Doing so will incapacitate any downstream renderer, but that's actually a good thing.

At least the strange MQA filters being applied in the renderer phase will not be used by going for the software route and doing just the first unfold.

So this part is basically a dynamic range limited baseband signal (because MQA uses 9 bits for the lossy HF part, encoded as hissing in the baseband signal) + recovered lossy ultrasonics mixed together.

I should still do the test how much diff can be heard between first unfold + sox minimum phase vs undecoded MQA + sox minimum phase.

Thanks to your work we can now dissect all parts of MQA and listen / evaluate each part. The black box is being deblurred part by part

[mansr]

48 minutes ago, soxr said:

At least the strange MQA filters being applied in the renderer phase will not be used by going for the software route and doing just the first unfold.

So this part is basically a dynamic range limited baseband signal (because MQA uses 9 bits for the lossy HF part, encoded as hissing in the baseband signal) + recovered lossy ultrasonics mixed together.

I should still do the test how much diff can be heard between first unfold + sox minimum phase vs undecoded MQA + sox minimum phase.

Thanks to your work we can now dissect all parts of MQA and listen / evaluate each part. The black box is being deblurred part by part

Undecoded MQA has additional noise that isn't part of the encoded upper band. It's just shaped dither from a specific pseudo-random number generator, and the first thing the decoder does is to reverse it. This noise is what gives the characteristic hump in the spectrum from 15 kHz and up.

[Wang Xuanqian]

MQA playback process contains two stage, unfold and upsampling. Actually, the first step already do upsampling as they need to convert audio to higher sampling rate so they can put the so called ultrasonic signal inside. 

 

The official MQA process has no magic or not anything impressive. They run the process on XMOS processor for their Meridian Explorer 2 DAC. XMOS is a 32bit processor with no floating point precision support and maximum calculation ability for one single thread is 100MIPS. You can not expect much from that kind of calculation ability.

 

A customized filter design by libsox can achieve much better result.

[labjr]

Is there some benefit to this upsampling and custom filters other than decoding MQA files? Because I don't plan to use Tidal or buy MQA files.

[Don Hills]

21 minutes ago, labjr said:

Is there some benefit to this upsampling and custom filters other than decoding MQA files? Because I don't plan to use Tidal or buy MQA files.

 

The thing that worries many people is that if MQA becomes "the standard", you won't be able to avoid using it.