Stereophile Series on MQA Technology

[Kal Rubinson]

1 hour ago, Ralf11 said:

a smear uses the temporal lobes

Particularly Heschl's Gyrus.

[christopher3393]

22 minutes ago, Kal Rubinson said:

Particularly Heschl's Gyrus.

 

mmm...now that makes me hungry!

[Ralf11]

1 hour ago, mansr said:

... I don't know what your background is, but your understanding of these matters is clearly confused...

 

He turned up at about the same time* that GUTB clocked out

 

just sayin'

 

 

*within the variance blur created by temporal schmear at any rate

[Ralf11]

you guys awakened a 'specific nutritional hunger' so I went down to the bagel place here and am enjoying it with a 17 year old Montagny

 

- best bagels within 100 miles

[mansr]

6 minutes ago, Ralf11 said:

He turned up at about the same time* that GUTB clocked out

It can't be GUTB. He hasn't said anything sucks.

[Ralf11]

ah but what if GUTB were deconvoluted ?

[pkane2001]

3 minutes ago, Ralf11 said:

ah but what if GUTB were deconvoluted ?

 

Impossible. Deconvolution does not work with such a low S/N ratio.

[Galileo365]

1 hour ago, mansr said:

 

I studied logic, math, computer science, philosophy, literature, and a field called semiotics at Stanford. The dictionary definition was meant to disambiguate the use of the term filter in the mainstream from how it applies to signal processing such as interpolation, although I did not make that exact point very clear. Fourier analysis is a family of mathematical techniques, all based on decomposing signals into sinusoids. The discrete Fourier transform (DFT) is usually  used with digitized signals. The shift theorem says that a delay in the time domain corresponds to linear phase, a property of a filter. The result is that all frequency components of the input signal are shifted in time by the same amount, referred to as the group delay. There is no phase distortion due to the time delay of frequencies relative to one another. The predominant type of digital filter used in audio is called an FIR (Finite Impulse Response) filter. High-quality sampling ensures that no aliasing occurs by lowpass filtering the signal. A example digital filter would bring a 24 kHz signal down to about -100db. That's a really stiff slope and, in analog electronics, the filter would have a phase shift or non-uniform delay from frequency to frequency. However, digital “filters” are different from analog “filters” because digital “filters” interpolate, an active process in the digital domain, not “filter” passively in the analog domain. So FIR digital “filters” have no group delay. That brings me around to my original point, that the word “filter” in the digital domain is a misnomer given the common meaning of “filter”. So insisting, out of context, using self-accolades and derogatory comments aboit me rather than elucidation (a rhetorical strategy as opposed to a logically deductive proof) that interpolation and filtering are the same thing in general will only confuse the layperson. The “time smearing” or phase shift I refer to occurs as the result of passive filtering in the analog domain, often but not always employed in DAC’s for the consumer market. So when you say that MQA uses “filters” as opposed to interpolation without explication, you are making an inherently ambiguous and self-contradictory statement. Trying to dazzle anyone with long lists of marhemstivsl terms to appear to have superior knowledge without actually disambiguating terms and saying precisely what you mean will not work on me. It’s the equivalent of robbing a bank and offering, as your defense, not if you did or did not rob the bank, but saying simply, “I’m not the kind of person who would rob a bank”. So either say what you mean or stop commenting in dismissive and derogatory ways, because you’re making an ass of yourself as opposed to actually informing anyone.

[mansr]

11 minutes ago, Galileo365 said:

However, digital “filters” are different from analog “filters” because digital “filters” interpolate, an active process in the digital domain, not “filter” passively in the analog domain.

That makes no sense.

[Galileo365]

2 minutes ago, mansr said:

That makes no sense.

 

It you read my post carefully, you will find the explanation. I don’t know if you have a background in analog electronics or just signal theory,, but certain terms overlap between the two areas with very different meanings, That's  the last word I have to say on the matter.

[mansr]

Just now, Galileo365 said:

It you read my post carefully, you will find the explanation.

I did, and I didn't. Far from any explanation, all you offer is a recital of trivial facts intermixed with confused, if not meaningless, interpretations thereof. You may have studied, but I question how much you learned.

 

[The Computer Audiophile]

14 minutes ago, mansr said:

I did, and I didn't. Far from any explanation, all you offer is a recital of trivial facts intermixed with confused, if not meaningless, interpretations thereof. You may have studied, but I question how much you learned.

 

Your response helps nobody. If something incorrect is posted please point it out. 

 

Its often not what you say but how you say it. Please be respectful of the community decorum. 

[mansr]

7 minutes ago, The Computer Audiophile said:

Your response helps nobody. If something incorrect is posted please point it out. 

 

Its often not what you say but how you say it. Please be respectful of the community decorum. 

I stand by what I've said, but I'll refrain from further responding on this topic. It is going nowhere.

[Audiophile Neuroscience]

4 hours ago, mansr said:

I stand by what I've said,

 

No-one would expect less.

 

4 hours ago, mansr said:

but I'll refrain from further responding on this topic. It is going nowhere. 

 

Why?

 

I agree with Computer Audiophile.

5 hours ago, The Computer Audiophile said:

Its often not what you say but how you say it.

 

Civility issues aside, I'd like to hear the clash of ideas not a clash of egos (yeah, you know, do as I say not as I do ? ). Not sure why the defensive posturing (IMO) on this one. Galileo is new to the forum, seems like he can and wants to contribute so why not cut him some slack.

[MikeyFresh]

10 minutes ago, Audiophile Neuroscience said:

Galileo is new to the forum, seems like he can and wants to contribute so why not cut him some slack.

 

Are you sure of that? I'm not.

 

21 total posts, exactly all of them in the thread, what is his industry/MQA affiliation, if any?

[Ralf11]

I'd like to hear more about the shift theorem and what it has to do with MQA

[Audiophile Neuroscience]

13 minutes ago, MikeyFresh said:

 

Are you sure of that? I'm not.

 

21 total posts, exactly all of them in the thread, what is his industry/MQA affiliation, if any?

 

I don't think you can know either way. I believe people should be afforded the benefit of the doubt. Not everyone with a variance of opinion is a shill.

 

people have been asked to put their industry affiliation in their signatures. We cannot be sure if anyone here has complied apart from a handful such as John Atkinson

[Galileo365]

21 minutes ago, MikeyFresh said:

21 total posts, exactly all of them in the thread, what is his industry/MQA affiliation, if any?

 

Quite sincerely and honestly, none whstsoever. I’m just trying to figure what it’s supposed to do, how it might work, and how to confirm that it does so. I would guess that most of those 21 posts involve defending myself for “asking stupid questions”.

[Audiophile Neuroscience]

15 minutes ago, Ralf11 said:

I'd like to hear more about the shift theorem and what it has to do with MQA

 

I also wondered about polynomial differential operators?

[Galileo365]

27 minutes ago, Ralf11 said:

I'd like to hear more about the shift theorem and what it has to do with MQA

 

Without going into a lot of detail right now because I’m tired of getting flamed, reversing engineering MQA DAC’s is fine if you know how an MQA ADC works, because it is not supposed to be based on Shannon signal theory. Assuming that only the Shannon sampling model is valid and assessing MQA DAC’s from that perspective is like only evaluating quantum mechanics from a Newtonian perspective. 

[Galileo365]

Myek is coming out with a consumer-level MQA ADC and, of course, they already make an MQA DAC. Ayre used to make a QA-9 and a QB-9 ADC and DAC, both of which you can find used. Take an analog recording, preferably from two-track R2R tape. Run that through an oscilloscope. Then connect the MQA ADC directly to the MQA DAC and the QA-9 to the QB-9. Run the signal from the tape through both parallel chains and analyze the output of both DAC’s with the oscilloscope. Then see if the trace on the MQA chain differs at all from the non-MQA chain and, if so, which trace more closely matches the pre-sampled trace. That will tell you more than reversing engineering an MQA DAC out of context. There may be no apparent difference at all or there might be but that’s hard empirical evidence. If all three traes look the same, perform some additional analysis using other measurement techniques to see if any difference ever shows up.

[MikeyFresh]

38 minutes ago, Galileo365 said:

Assuming that only the Shannon sampling model is valid and assessing MQA DAC’s from that perspective is like only evaluating quantum mechanics from a Newtonian perspective. 

 

Or, it's like saying "MQA is many things", and "you don't truly understand MQA" , or it's all hidden behind a very clever NDA so good luck in getting any firm understanding.

 

With all due respect, do you really think BS, Stereophile, TAS, et al. have provided any real response or rebuttal to the findings of @Archimago, or @mansr, or @FrederickV among others? (They haven't).

 

Or are you attempting to do that in their conspicuous absence?

 

[Brinkman Ship]

1 hour ago, MikeyFresh said:

 

Are you sure of that? I'm not.

 

21 total posts, exactly all of them in the thread, what is his industry/MQA affiliation, if any?

Sniff sniff...hmmmm...fee fie fo fum...I smell the blood of an MQA Shill....?

[mcgillroy]

An MQA-ADC?! Where? Nobody has seen any in the wild and it’s questionable if they exist.

 

Prediction: that Mytek device if it ever appears will only lead to further disenchantment with MQA.

[Audiophile Neuroscience]

 

double post