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"MQA One Year Later -- Suddenly, More Questions"

What is "rendering" wrt MQA? Audivana3 renders ( which I guess is different to decoding) Tidal Masters, but I don't know what the term rendering actually means in hifi terms.

A buzz phrase for a decoding step where the complete decoding is done in stages, AFAIK. The other cute phrase is "unfolding" that describes a particular decoding process. Others here may elaborate or correct.
 
What is "rendering" wrt MQA?


core (decoding) =

Unfolding of an MQA encoded 48k (or 44.1k) file to 96k (or 88.2k). This process retrieves the ultrasonic signal that was hidden below the baseband (<24kHz) by the origami process.
This process is relatively computationally complex, and requires a fair bit of processing power that is not generally available in the silicon of any old(er) DAC.

rendering =

The upsampling of a core-decoded signal to whatever was the master's original sample rate (96, 192, 384, ...), using MQA-style filters (meaning short in the temporal domain, but leaky in the frequency domain and hence generating spurious images).
This process is fairly simple and can be done on any DAC chip that allows user-defined filters, or even on DACs with a small microprocessor somewhere in the signal path.
 
FWIW I tend to use 'rendering' in this context to mean "the entire process from starting with the input data to producing an analogue result. (Here the input data is what we downloaded, or bought on an "MQA Audio CD" (sic) or whatever we were given as MQA material)

Thus I can use "Rendered as if LPCM" to mean using a non-MQA DAC/software and "Rendered as MQA" to mean using an MQA DAC/software. One of my concerns about MQA is the impact it may have on results when 'rendered as if LPCM'. i.e. the effect on the rest of us if we find that the only version of something is MQA when we don't have an MQA playing system.

As in the past, this may not matter much for something 48k/24bit MQA material. But it might mean that 'Audio CD' material (44.1k/16) that has been MQA encoded will be noticably impacted when rendered by a non-MQA player/DAC.

Note that I use 'unfolding' differently to Werner above. To me the process of using LSB hidden HF hints to regenerate a higher rate output is using bitstracking. So might be called 'unstacking' when decoded.

I keep the terms 'folding' and 'unfolding' for the non-Nyquist used of HF aliases/images rather than using LSB info. The two processes are quite different, and have separate MQA Patents. but MQA may cascade them.

e.g. if you start with 192k material you might use 'folding' to get 96k. Then 'bitstacking' to give you 48k results, hiding the HF hints from the 96k input in the lowest bits of the output.

Rendering then would require 'unstacking' the 48k back into a 96k series of samples, then 'unfolding' this to get 192k.

What's unclear is just how much of the original HF this recovers or represents. It seems clear that the result in general will differ from the source if we compared the 192k source with the 'MQA rendered' output on a sample-by-sample basis. How much that matters is also unclear. Hidden by the secret sauce.
 
BTW strictly speaking the 'folding' and 'unfolding' processes above are nominally doable using analogue methods. In effect, IF mixing, etc as known to RF engineers. Indeed, anyone familiar with Radar Warning Receivers will know how to 'fold down' wideband signals. However they may have to shoot you before they got too specific. 8-]
 
:rolleyes:

SJS Arcadia Model 1.5 Line preamp (off being upgraded with duelund caps etc)
SJS Arcadia Model 5 SE 300B Power Amplifier - Western Electric 300b - Mullard GZ37 - Sylvania 6sn7
Modwright LS100 - Mullard GZ34 - USA TungSol 6sn7
Tune Audio Prime speakers
Audio Note 4.1 DAC
Origin Live Resolution mk3 - Audio Note Arm One v2 - Decca Gold
Whest PS.30 rdt Special Edition
 
I summarize this article as saying that MQA is audibly transparent to what seems to be a HDTracks source and that there is no sign of the highly touted ADC compensation. The spurious artifacts are insignificant (but this is 24 bit, the MQA on CD case needs more testing)

So MQA is an over complex ( to be patentable ) way of doing what FLAC or WavPack could have done anyway.
 
I summarize this article as saying that MQA is audibly transparent to what seems to be a HDTracks source and that there is no sign of the highly touted ADC compensation. The spurious artifacts are insignificant (but this is 24 bit, the MQA on CD case needs more testing)

So MQA is an over complex ( to be patentable ) way of doing what FLAC or WavPack could have done anyway.


Considering Archimago's conclusions regarding Chromecast Audio's sound quality:

"From a subjective perspective, what else does one really need? I would certainly have no qualms about using the analogue output from this remarkably economical device to feed a good stereo system.
"

I don't think it's worth bothering too much about his musings. Some of his opinions/ conclusions are quite laughable​ IMO.
 
Some people focus on facts, others on discrediting the messenger.

When the messenger comes to ridiculous conclusions it's hard to give much credibility to the "facts" he supposedly conveys.
As John Westlake once said:

"I read some of "archimago" postings and as a result dont give him much time as he blankly discounts certain aspects of Digital Audio that I do know have a significant impact on audio quality.

Its one thing to "repeat" theory without practical experience on the impact to sound quality - its another to actually have some working practical experience where you become forced to question your own preconceived ideas and biases – I guess this happens in any field of research though practical application."
 
Considering Archimago's conclusions regarding Chromecast Audio's sound quality:

"From a subjective perspective, what else does one really need? I would certainly have no qualms about using the analogue output from this remarkably economical device to feed a good stereo system.
"

I don't think it's worth bothering too much about his musings. Some of his opinions/ conclusions are quite laughable​ IMO.

My system is far from high end but I use a CCA.

Imho the sound from the analogue out is good. I use it with a Spdif Hifimediy 9018k2m Sabre DAC.

Improvements? A smidgen more perceived detail and stage width at cost to a little upper mid/treble sheen. - I will try a battery supply for 16 quid as recommended by KennyH to see if this further improves SQ.

I could very happily live just with the CCA. - Remarkable vfm.

Others may disagree.
 
My system is far from high end and I use a CCA.

Imho the sound from the analogue out is good. I use it with a Spdif Hifimediy 9018k2m Sabre DAC.

Improvements? A smidgen more perceived detail and stage width at cost to a little upper mid/treble sheen.

I could very happily live just with the CCA. - Remarkable vfm.

Others may disagree.

I have a Chromecast Audio in my setup.

Even its digital out is somewhat poor IME.

Adding an iFi SPDIF purifier to feed a Mytek Brooklyn things get better but not as good as using a Bluesound Node 2 as digital transport.

Great value for money though I agree.
But using its analog out without any qualms in a good stereo setup?! :D
 
I have a Chromecast Audio in my setup.

Even its digital out is somewhat poor IME.

Adding an iFi SPDIF purifier to feed a Mytek Brooklyn things get better but not as good as using a Bluesound Node 2 as digital transport.

Great value for money though I agree.
But using its analog out without any qualms in a good stereo setup?! :D

Perhaps your system is that much better I don't know.

Imho differences between DAC'S are perhaps over rated these days. They all seem to perform pretty much above of what seems audible and beyond any other part of the chain in the system.

Moving speakers an inch perhaps makes more difference?

I would not pay a fortune for a streaming solution DAC and much rather invest the cash elsewhere in the system but the Brooklin is admittedly more than just a DAC.
 
Perhaps your system is that much better I don't know.

Imho differences between DAC'S are perhaps over rated these days. They all seem to perform pretty much above of what seems audible and beyond any other chain in the system.

Moving speakers an inch perhaps makes more difference?


I have had the chance of comparing different DACs in my setup (even blind a couple of times).

And to my ears there are very important differences in terms of sound quality especially in terms of timing precision, sound stage and detail.
 
His conclusions about a Chromecast Audio's analog out being suitable for a good stereo setup.

Ah, so he is laughably wrong because his opinion is different from yours?

In what (factual) way is the chromecast audio analog out not suitable for a good stereo setup?
 
My system is far from high end but I use a CCA.

Imho the sound from the analogue out is good. I use it with a Spdif Hifimediy 9018k2m Sabre DAC.

Are you saying you use the Chromecast connected to your DAC?
What different configurations were your observations describing?
 


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