AudioQuest adds MQA Support to Dragonflies via firmware

[mansr]

14 hours ago, abrxx said:

For those saying that MQA doesn't upsample (or downsample), it might be worth looking at what Bob actually wrote in his patent application for the "rendering" part of the process:

 

https://worldwide.espacenet.com/publicationDetails/originalDocument?CC=WO&NR=2014108677A1&KC=A1&FT=D&ND=3&date=20140717&DB=EPODOC&locale=en_EP

 

Remember, MQA has many different parts, and the above patent only describes one part of the machine.

That document certainly describes a downsampling for distribution followed by upsampling at playback. It even uses those very words. How novel.

[Jud]

19 hours ago, PeterSt said:

 

Completely correct. But this doesn't mean that #2 is upsampling.

Upsampling = fake. And this is not what MQA provocates (same as a native 96 file which is unfolded to that, taking distance from how lossy that is or not). OK ?

 

19 hours ago, mansr said:

It wouldn't have to be, but it is.

No matter what MQA tries to claim, "rendering" to higher sample rates than 96 kHz is upsampling. Because of the leaky filters used, the upsampled signals contains strong images of the 0-48 kHz frequencies which might be mistaken for restored content. The original high frequency-content is simply not stored anywhere in the file, so there is no way to reconstruct it.

 

19 hours ago, Wavelength said:

Peter,

 

Thanks, this is exactly what I have been saying!

 

OK @PeterSt, a little confused with you "liking" @mansr's post, then Gordon agreeing with you but apparently disagreeing with @mansr, but let me see if I've got your original meaning correct: Upsampling would be done with the intention of accurate reconstruction (perhaps concentrating primarily on frequency response), but certainly for anything above a 96KHz sample rate and very possibly even below that rate, MQA's concentration is not on that sort of reconstruction.

[PeterSt]

@Jud I can't help it that the official documents are so clumsy to talk about downsampling and upsampling, but I'm afraid that the downsampling can not be avoided (that is just what it is) so to call the reconstruction upsampling is almost a logical thing. Or call it deconstructing (oops) and reconstructing.

 

Anyway you got my thinking right. And this includes the impossibility of judging what the real merits of matters are. Maybe it helps if I say that I did not express an opinion, but a translation of what's expressed by MQA. So no matter what one might like to read in/from the Patent(s), officially there is a (code) difference between unfolding to the original sampling rate and upsampling further from there.

Easy to get mixed feelings about my drifting between what is and what should be.

 

 

[miguelito]

20 hours ago, DarwinOSX said:

 

Bob Stuart talks about three unfolds.

 

 

No he does not. Three regions, two "folds".

 

Moreover, he says that region C is "noise" that allows the DAC to work at a higher speed. This is pretty much what upsampling does: guess higher frequency information such that you don't need a brickwall filter with all it's phase (ie time blurring) issues. This video is pretty convincing that what is done to "recover" C is pure upsampling.

[Jud]

4 minutes ago, miguelito said:

guess higher frequency information

 

For MQA above 48K it apparently isn't even doing that.  But for non-MQA more typical upsampling situations, the information is much better than a guess, and does not involve frequencies that would have been "illegal" at the original sample rate.

[Fokus]

21 hours ago, mansr said:

No matter what MQA tries to claim, "rendering" to higher sample rates than 96 kHz is upsampling. Because of the leaky filters used, the upsampled signals contains strong images of the 0-48 kHz frequencies

 

This page http://www.pinkfishmedia.net/forum/showthread.php?t=198428&page=42 contains spectra of what appear to be '192kHz' MQA files, played back through an MQA DAC and then recaptured by a 192k ADC. Nearly all of them have clear signs of leaky upsampling above 48kHz.

 

[bobbmd]

On 5/23/2017 at 11:16 AM, Wavelength said:

 

First DragonFly's max sample rate is 96KHz. So the data going to the dac cannot exceed that. Others here will say they know what goes on here, but I will say I don't. I don't know what the application does in the case of sample rates above the 96K threshold of the dac. Sure I could guess as they do, but I would rather not mislead you.

 

If the MQA LED goes Purple then you know your getting the best possible results from the file you are playing.

 

Thanks,

Gordon

gordon: then why does audirvana A+3 say in the upper left hand corner (at times) 24/192(with NO  MQA indication) and in upper right corner say MQA with blue dot FLAC stereo 24/192? the AQDFR shows the magenta color? It sounds great but what am i getting?  please note this is not a critical or accusatory comment(i feel bad for the abuse you are getting) bobbmd 

[mansr]

9 hours ago, bobbmd said:

gordon: then why does audirvana A+3 say in the upper left hand corner (at times) 24/192(with NO  MQA indication) and in upper right corner say MQA with blue dot FLAC stereo 24/192? the AQDFR shows the magenta color? It sounds great but what am i getting?  please note this is not a critical or accusatory comment(i feel bad for the abuse you are getting) bobbmd 

Could it be that A+ displays the format of the file rather than what is sent to the DAC? If the file sample rate exceeds what the DAC supports, it is presumably downsampled. If there's one thing everybody agrees on, it's that the Dragonfly is limited to 96 kHz input.

[miguelito]

15 minutes ago, mansr said:

Could it be that A+ displays the format of the file rather than what is sent to the DAC? If the file sample rate exceeds what the DAC supports, it is presumably downsampled. If there's one thing everybody agrees on, it's that the Dragonfly is limited to 96 kHz input.

That's what it does. The MQA file includes information on how high to upsample. So for example Joni Mitchell's 'Both Sides Now' only goes to 96KHz (ie no upsample in the DAC, possibly some filter applied), whereas some 2L recordings indicate 352KHz (which I take MQA is telling the DAC to upsample the incoming 88KHz stream to 352KHz).

 

The fact that the DF is limited to 96KHz is fine as the first unfold never goes beyond that anyway.

[bobbmd]

@mansr@miguelito: thanks but it STLL sounds wonderful-now WHAT am I getting since I use an apple airport express as my wifi something LESS than I think I am getting? AND the AQDFR actually makes Pandora sound better in my car but Spotify doesn't sound as good

bobbmd

[ShawnC]

Here's Han's review

 

 

[rickca]

On 5/23/2017 at 0:00 PM, PeterSt said:

I don't think this is information which can harm MQA and it is the truth of functional outcome anyway. Besides that it is clear that readers mostly lack this knowledge, so I hope this helps someone.

This is a brilliant post, Peter!

[miguelito]

On 5/26/2017 at 8:39 PM, ShawnC said:

Here's Han's review

 

 

This review is all wrong. He has no idea how this works and it can make people misunderstand how to use the DF to render MQA. 

 

And btw, he is NOT decoding MQA at all! What a moron.

[PeterSt]

On 2017-5-27 at 2:39 AM, ShawnC said:

Here's Han's review

 

Oh that Hansss.

If I had known that it was him I would have looked into that right away ...

... to see what non-sense he came up with this time ...

 

Some times I feel I need to apologize to live in this country. 

[jtwrace]

I tried MQA with my Mytek Brooklyn.  I'm not impressed in the least.  In fact I think it's terrible.  

[rickca]

1 hour ago, jtwrace said:

I tried MQA with my Mytek Brooklyn.  I'm not impressed in the least.  In fact I think it's terrible.  

The MQA thought police are all upset now.  Can you expand on why you find it terrible?

[jtwrace]

Just now, rickca said:

The MQA thought police are all upset now.  Can you expand on why you find it terrible?

I find it incredibly harsh and very unnatural.  I'll stick with my Redbook upsampled via Roon and call it a day.  

[ShawnC]

Here's his apology

[crenca]

5 hours ago, ShawnC said:

Here's his apology

 

Good for him...but he is still an MQA evangelist

 

If one believe as he does, that there is something fundamentally wrong with PCM ("in the midrange" as he says) that can only be fixed with tech of the psycho-acoustic variety, then why MQA?  Why an "end to end" and all the drawbacks that incurs for everyone in the industry and consumers?  Why a proprietary and not an open solution?  

 

As he admit's, he wants MQA to "succeed" so I am weary of his affirmations that he is willing to criticize it. 

[ShawnC]

...and his finally.  This concludes Han's video trilogy 

[mansr]

Archimago got his hands on a DF, and I helped him make some test signals:

http://archimago.blogspot.com/2017/06/measurements-audioquest-dragonfly-black_24.html

[firedog]

1 hour ago, mansr said:

Archimago got his hands on a DF, and I helped him make some test signals:

http://archimago.blogspot.com/2017/06/measurements-audioquest-dragonfly-black_24.html

Read the post. 

One question: the article implies that all the renderer is doing is applying a filter and possibly also upsampling.

Are you sure this is all it is doing?

[mansr]

1 hour ago, firedog said:

One question: the article implies that all the renderer is doing is applying a filter and possibly also upsampling.

Are you sure this is all it is doing?

The renderer does two things, upsample and dither. The filter discussed is the one used in upsampling.

[firedog]

7 hours ago, mansr said:

The renderer does two things, upsample and dither. The filter discussed is the one used in upsampling.

So you are saying that the claimed "deblurring" is simply the use of minimum phase filter, nothing else?

[mansr]

6 hours ago, firedog said:

So you are saying that the claimed "deblurring" is simply the use of minimum phase filter, nothing else?

I have no idea which part is responsible for "deblurring" since it's not clear what that is even supposed to mean.