John Atkinson: Yes, MQA IS Elegant...

[Ryan Berry]

1 hour ago, crenca said:

 

 

Thank you @mansr for these cogent replies.  Also, thank you @Ryan Berryfor your reply and insight into Charley's posititions.  Ryan, as you can tell part of the context of @John_Atkinson selling support of MQA is this alleged "end to end" ADC to DAC linking, hand off, and design "synergy".  Yet as mansr is pointing out there appears to be little (any?) technical explication behind it.  In the end, we are dealing with PCM and PCM is a mature algorithmic process for digital sampling/encoding of audio.  As mansr explains the relationship between the implementation of the ADC and the DAC is not normally described as "end to end" as if it is somehow efficacious (or even necessary) for one to directly account for the other or be sold in a product bundle like MQA tries (but fails) at doing.  As long as each "do their jobs" so to speak, there is no real "end to end" relationship.

 

I suspect that all you/Charlie/Ayre mean to say is the QA-9 samples at 192khz, and thus the "end to end" implication is thus the reconstruction filter on the DAC end has plenty of "headroom" for it's design choices.  If something is implied beyond the sampling rate and/or the good internal design choices of the QA-9, I along with mansr would like to see a technical explanation.

 

First, apologies for the spelling, Mansr.  When one is typing, "autopilot" can take over and use the wrong version of a word and there's nothing available to catch the issue for you.  Fortunately, you seem to have caught the meaning.

 

Reading through the post, I clearly made an error in stating things definitively when I should have stated them as Charley's theories.  Unfortunately, with Charley's passing, I can't say with authority what his ultimate intention was with the filters outside the fact that we never really talked about them after trying it out.  Ariel knows a fair bit more about digital filters than I do, but even then, the filter ended up being not viable to pursue so it's really not a factor today for us.  I do know that he kept the filters in his home system until his passing, but whether that was a result of thinking they were worth pursuing or because he just never got around to having us take his system apart to update everything (the more likely scenario), I cannot say.  When we listened to them with any commercial recording we were rather unimpressed, so we had no desire to really spend any more time on it.

 

I wish there was more of an exciting story to share there, but there really isn't.  It was an experiment, and if I went down the list of the hundreds of experiments we've performed at Ayre and dug into explanations of why they didn't ultimately work, I'd never get anything else done!  Ultimately, it was a theory that may have worked but had enough issues that we didn't spend more time on it.  The best person to explain the thinking behind it is now gone and considering the low amount of time we spent on it or even discussing it, it just doesn't seem to be a technology worth wrapping our heads around here today.  I can say that the filters weren't simply mirrors of one another, as between the downsampling of the ADC and the upsampling of the DACs it just doesn't work that way, so the filter was a very, very simple approximation only to start with to test that never went much further.  

[Jud]

25 minutes ago, Ryan Berry said:

When we listened to them with any commercial recording we were rather unimpressed

 

Interesting.

[mansr]

6 minutes ago, Ryan Berry said:

Reading through the post, I clearly made an error in stating things definitively when I should have stated them as Charley's theories.  Unfortunately, with Charley's passing, I can't say with authority what his ultimate intention was with the filters outside the fact that we never really talked about them after trying it out.  Ariel knows a fair bit more about digital filters than I do, but even then, the filter ended up being not viable to pursue so it's really not a factor today for us.  I do know that he kept the filters in his home system until his passing, but whether that was a result of thinking they were worth pursuing or because he just never got around to having us take his system apart to update everything (the more likely scenario), I cannot say.  When we listened to them with any commercial recording we were rather unimpressed, so we had no desire to really spend any more time on it.

 

I wish there was more of an exciting story to share there, but there really isn't.  It was an experiment, and if I went down the list of the hundreds of experiments we've performed at Ayre and dug into explanations of why they didn't ultimately work, I'd never get anything else done!  Ultimately, it was a theory that may have worked but had enough issues that we didn't spend more time on it.  The best person to explain the thinking behind it is now gone and considering the low amount of time we spent on it or even discussing it, it just doesn't seem to be a technology worth wrapping our heads around here today.  I can say that the filters weren't simply mirrors of one another, as between the downsampling of the ADC and the upsampling of the DACs it just doesn't work that way, so the filter was a very, very simple approximation only to start with to test that never went much further.  

After reading all that, I still have no idea what you might have meant by "complementary filters," and I get the impression that you don't either. At least you have the courage to admit that, if in a somewhat verbose way. Anyhow, whatever Charley Hansen's ideas were, the MQA people might mean something entirely different. This time around, it was John Atkinson who brought it up, and he refuses to explain what he means, despite claiming to understand it.

[Shadders]

Off topic - deleted.

 

[Ryan Berry]

Just now, mansr said:

After reading all that, I still have no idea what you might have meant by "complementary filters," and I get the impression that you don't either. At least you have the courage to admit that, if in a somewhat verbose way. Anyhow, whatever Charley Hansen's ideas were, the MQA people might mean something entirely different. This time around, it was John Atkinson who brought it up, and he refuses to explain what he means, despite claiming to understand it.

Perhaps more accurately, there's really no complementary filter at all in the way you were interpreting it (ie. reconstructing as a reverse of sampling, or a perfectly matched filter).  As the very premise of your argument with Charley's theory doesn't exist, it makes the rest of the point rather moot.  Unfortunately he isn't around to carry it further with you.  I see nothing else in the post worth debating, really.

[mansr]

6 minutes ago, Ryan Berry said:

Perhaps more accurately, there's really no complementary filter at all in the way you were interpreting it (ie. reconstructing as a reverse of sampling, or a perfectly matched filter).  As the very premise of your argument with Charley's theory doesn't exist, it makes the rest of the point rather moot.  Unfortunately he isn't around to carry it further with you.

As I still don't know what that theory is, I can't be having an argument with it. The obvious interpretation of the word complementary doesn't make sense, and you say that isn't what he meant anyway, so I guess we sort of agree there.

 

6 minutes ago, Ryan Berry said:

I see nothing else in the post worth debating, really.

I'm not looking for a debate. All I want is to understand what people mean when they use certain terms. It is impossible to conduct a conversation without first having a basic agreement on the meaning of the words used therein.

[crenca]

Interesting, perhaps Charley did mean something other than high(er) sample rates by "complimentary"... Still whatever he meant it seems to have been lost.

 

Whatever MQA means by it the burden of proof is on them...

[Shadders]

15 minutes ago, crenca said:

Interesting, perhaps Charley did mean something other than high(er) sample rates by "complimentary".

 

[Ralf11]

 the burden of poof is on MQA

[Le Concombre Masqué]

On 8/20/2018 at 11:30 PM, FredericV said:

The end to end argument requires drivers which do not smear the time domain:

Example: bending wave driver:

 

Ribbons:

 

vs dynamic drivers (e.g. Wilson (source ) )

 

Most dynamic drivers can't stop the motion immediately, therefore never being able to recreate the time domain accurately. Most tweeters are just not fast enough to correctly playback non-periodic sounds & events.

Bass reflex also has an added time delay, therefore smearing the time domain.

Fix the speakers first, the errors here are much larger than what MQA is trying to solve.

Most speakers fail this test:

 

They can't reproduce the point source of the clapper hitting the bell, while they can reproduce the resonance of the bell. Frequency domain is not the issue here, but the time domain is.

 

You're right : there are more fundamental things to do when you have the privilege to talk to music producers, recording and mastering engineers as MQA people claim they do, such as making sure they use a calibrated  Stereo system and calibrating yours. However, I think loudspeakers can perform better than what you expect ; try REW + Rephase ; I get this from my Cabasse (30 years old dynamic drivers, pre SCS) 

[Shadders]

56 minutes ago, Le Concombre Masqué said:

You're right : there are more fundamental things to do when you have the privilege to talk to music producers, recording and mastering engineers as MQA people claim they do, such as making sure they use a calibrated  Stereo system and calibrating yours. However, I think loudspeakers can perform better than what you expect ; try REW + Rephase ; I get this from my Cabasse (30 years old dynamic drivers, pre SCS) 

Hi,

Yes - speaker distortion can be single digit figures, so my interpretation is that any changes to mastering, or the use of high resolution(PCM, DSD, MQA) is completely lost.

As you have stated, REW etc., has such a major change in sound, that any gains from CD to high resolution are minimal by comparison. I have seen many reports that using miniDSP had such a positive benefit to the sound.

 

In the big scheme of things, the continued support and promotion of MQA is comical. No one in the normal world cares about high resolution - let alone a new format. People are happy with MP3. The revenue from extra sales of MQA must be non existent.

 

So why do some Hifi spokes people persist in promoting MQA ?.

 

Like VHS to DVD, the step change was major and everyone could see it, so too was the change from LP to CD (hear it).

 

Why the record companies are even supporting MQA has to mean that there is another reason other than sound quality. They must be aware of the decimation of the hifi industry, where high resolution is becoming inconsequential.

 

So, to @John_Atkinson why do you still promote MQA in any fashion, if no one really cares (in the real world) ???.

 

[i assume that it is because your job is in hifi, and it is just another wheeze].

 

Regards,

Shadders.

[FredericV]

7 hours ago, Le Concombre Masqué said:

You're right : there are more fundamental things to do when you have the privilege to talk to music producers, recording and mastering engineers as MQA people claim they do, such as making sure they use a calibrated  Stereo system and calibrating yours. However, I think loudspeakers can perform better than what you expect ; try REW + Rephase ; I get this from my Cabasse (30 years old dynamic drivers, pre SCS) 

 

One SOX filter with parameters as measured by REW solved a big room issue here in our dev room.

[Le Concombre Masqué]

I too would advocate for fast rise times amps etc and my rational for the (slight but consistent) benefit of hires over redbook when each and every source benefits from HQP's upsampling filters is better transients.

And I too readily join the MQA bashing team.

However, liking what "MQA style" does to redbook is not necessarily dishonest IMO since I consistently like HQP's polysinc mqa mp filter with redbook material; ie today listening to Neil Young's Weld.

So, maybe, rather that doubting that people can like something about MQA, I'd stress that whatever is to like might be obtained elsewhere, wether a true benefit or a flavour to liken for a while, WITHOUT all the dark side. I've never actually heard MQA neither do I care to do so but I think plausible it's a way to make redbook palatable ; just a way that is obsolete from the start and plain bad when it comes in the way of non degraded sources (that might be another way to write hires) and high class players that can provide MQA style just as a flavour, sometimes worth trying, but don't present it as nec plus ultra.

[tmtomh]

I find it noteworthy that @John_Atkinson's article frames itself as a response to the criticism that he's called MQA "elegant." Given that "elegance" isn't the description for which Atkinson has gotten the bulk of the criticism directed at him in what he calls the "fracas" over MQA, it appears he's cherry-picking the criticism he wants to defend himself against, which has the ancillary effect of absenting all other criticisms of his pro-MQA statements from the article.

 

That said, I think his article is a very well-written, informative recitation of the case for minimizing pre-ringing (aka prioritizing time-domain accuracy) in digital filtering. Anyone who's not already well-versed in this issue (either by professional training or from doing a lot of reading) would, I think, benefit from it.

 

There does seem to be one major logical (or perhaps evidentiary) gap in the piece, though: He cites a listening test that failed to turn up audible evidence that pre-ringing causes problems (except in an intentionally worst-case filter where all the ringing is pre-ringing). Then almost immediately he nevertheless speculates that pre-ringing nevertheless could be an issue (by wondering if higher sample rates are pleasing to folks because they move ringing out of the audible range) - and then quickly moves on from there to strongly imply that pre-ringing is indeed a problem, despite the lack of evidence in the listening test mentioned just a couple of paragraphs above.

 

Folks can of course read the piece for themselves, so they don't have to blindly accept my characterization of it - the portion I'm referring to is on Page 2 of the web article linked to in the first post of this thread.

[crenca]

43 minutes ago, tmtomh said:

There does seem to be one major logical (or perhaps evidentiary) gap in the piece, though: He cites a listening test that failed to turn up audible evidence that pre-ringing causes problems (except in an intentionally worst-case filter where all the ringing is pre-ringing). Then almost immediately he nevertheless speculates that pre-ringing nevertheless could be an issue (by wondering if higher sample rates are pleasing to folks because they move ringing out of the audible range) - and then quickly moves on from there to strongly imply that pre-ringing is indeed a problem, despite the lack of evidence in the listening test mentioned just a couple of paragraphs above.

 

Is that even true?  I was thinking linear phase & min phase filters are frequency independent when it comes to "ringing"...

 

When you watch something like this, you begin to see that the relationship between linear and min phase, EQ, and recording in general is in no way simple and that the audiophile world of John Atkinson is simplistic and idiosyncratic at best.  In other words, what does John really know about "ringing" and how a recording should be treated by filtering and whether "ringing" comes into play?  Does what he thinks he knows really add up to much?  I suspect not.  The video starts off with an extreme EQ/mixing example where they make "ringing" audible:

 

 

[Shadders]

44 minutes ago, tmtomh said:

There does seem to be one major logical (or perhaps evidentiary) gap in the piece, though: He cites a listening test that failed to turn up audible evidence that pre-ringing causes problems (except in an intentionally worst-case filter where all the ringing is pre-ringing). Then almost immediately he nevertheless speculates that pre-ringing nevertheless could be an issue (by wondering if higher sample rates are pleasing to folks because they move ringing out of the audible range) - and then quickly moves on from there to strongly imply that pre-ringing is indeed a problem, despite the lack of evidence in the listening test mentioned just a couple of paragraphs above.

Hi,

From:

https://ccrma.stanford.edu/~jos/filters/Linear_Phase_Really_Ideal.html

 

Listening tests confirm that the ``pre-ring'' of the zero-phase case is audible before the main click, giving it a kind of ``chirp'' quality. Most listeners would say the minimum-phase case is a better ``click''. Since forward masking is stronger than backward masking in hearing perception, the optimal distribution of ringing is arguably a small amount before the main pulse (however much is inaudible due to backward masking, for example), with the rest occurring after the main pulse.

 

Regards,

Shadders.

[mansr]

27 minutes ago, Shadders said:

From:

https://ccrma.stanford.edu/~jos/filters/Linear_Phase_Really_Ideal.html

 

Listening tests confirm that the ``pre-ring'' of the zero-phase case is audible before the main click, giving it a kind of ``chirp'' quality. Most listeners would say the minimum-phase case is a better ``click''. Since forward masking is stronger than backward masking in hearing perception, the optimal distribution of ringing is arguably a small amount before the main pulse (however much is inaudible due to backward masking, for example), with the rest occurring after the main pulse.

That's testing a filter with a cutoff frequency of 2 kHz. Of course the ringing is audible, especially when listening to the worst case, the impulse response itself. Move it up above 20 kHz, and things change.

[Shadders]

3 minutes ago, mansr said:

That's testing a filter with a cutoff frequency of 2 kHz. Of course the ringing is audible, especially when listening to the worst case, the impulse response itself. Move it up above 20 kHz, and things change.

Hi,

One aspect is, that the issue of ringing when audible has been tested and results provided. Even at 20kHz cut off, ringing exists. Maybe you cannot hear that frequency ?

 

Have you analysed the ringing ?. If you use Octave and implement a linear phase filter for example, and a very slow ramp, 0volts to peak 1volt in 1 second, there is still ringing - albeit extremely low level - you have to zoom into the waveform. I have not analysed how this transfers into 16bit word, or 24bit words.

 

The ringing amplitude is directly proportional to the rate of change of the input signal. It has an envelope too, and is not just a pure cut off frequency tone.

 

Regards,

Shadders.

[mansr]

10 minutes ago, Shadders said:

One aspect is, that the issue of ringing when audible has been tested and results provided. Even at 20kHz cut off, ringing exists. Maybe you cannot hear that frequency ?

Of course I can't hear 20 kHz. Nobody above the age of 12 can.

[Shadders]

Just now, mansr said:

Of course I can't hear 20 kHz. Nobody above the age of 12 can.

Hi,

People can at the age of up to 25 can hear at 17.4kHz - there are security speakers - the Mosquito anti-loitering :

 

https://en.wikipedia.org/wiki/The_Mosquito

 

I expect that there are some in this age range from 18 to 25 who can hear 20kHz

 

Regards,

Shadders.

[mansr]

11 minutes ago, Shadders said:

People can at the age of up to 25 can hear at 17.4kHz - there are security speakers - the Mosquito anti-loitering :

 

https://en.wikipedia.org/wiki/The_Mosquito

 

I expect that there are some in this age range from 18 to 25 who can hear 20kHz

I haven't been 25 in a long time. Besides, not even an 18-year-old can hear 20 kHz sounds 60 dB or whatever below the music in the sub-10 kHz range. That page you linked proves nothing of relevance whatsoever.

[Fokus]

6 hours ago, Shadders said:

Have you analysed the ringing ?.

 

Often. Analysed, and studied the literature about it.

 

And guess what. Even when the frequency of ringing is audible to the test person, as in the 2kHz example, this in itself does not mean that the ringing is audible. The audibility depends on how the temporal spread compares to the inverse of the cochlea's critical band width at that frequency.

 

 

[Shadders]

8 hours ago, mansr said:

I haven't been 25 in a long time. Besides, not even an 18-year-old can hear 20 kHz sounds 60 dB or whatever below the music in the sub-10 kHz range. That page you linked proves nothing of relevance whatsoever.

Hi,

You have no proof that a person in the age range 18 to 25 cannot hear 20kHz. The mosquito product works at 17.4kHz so as to ensure it works on most humans up to the age of 25.

 

I have no proof that every 18 to 25 year old can hear 20kHz, but there will be some people in that range that can.

 

The original point of my post is that ringing preferences have been characterised, regardless whether people can hear 20kHz or not.

 

Regards,

Shadders.

[mansr]

1 hour ago, Shadders said:

You have no proof that a person in the age range 18 to 25 cannot hear 20kHz. The mosquito product works at 17.4kHz so as to ensure it works on most humans up to the age of 25.

 

I have no proof that every 18 to 25 year old can hear 20kHz, but there will be some people in that range that can.

 

The original point of my post is that ringing preferences have been characterised, regardless whether people can hear 20kHz or not.

Nobody is denying that young people can hear up to 20 kHz. However, even in a child, their sensitivity at 20 kHz is nowhere near what it is below 10 kHz. Now look at the frequency spectrum of actual music. In a typical recording, the level at 20 kHz is 30 dB or more below the intensity of any frequency in the main content region. If the total power of the actual music is compared to that of the "ringing," the difference is much larger. A test at 2 kHz tells absolutely nothing about the audibility of these effects at 20 kHz. Besides, for CD audio, we're talking about 22 kHz, and very few people indeed can hear that high, even when young. Still, let's say there is a slim chance that a 4-year-old with bat-like hearing might find the "ringing" displeasing. To avoid this, simply move it up to 48 kHz. There nobody can possibly hear it.

[Shadders]

17 minutes ago, mansr said:

Nobody is denying that young people can hear up to 20 kHz. However, even in a child, their sensitivity at 20 kHz is nowhere near what it is below 10 kHz. Now look at the frequency spectrum of actual music. In a typical recording, the level at 20 kHz is 30 dB or more below the intensity of any frequency in the main content region. If the total power of the actual music is compared to that of the "ringing," the difference is much larger. A test at 2 kHz tells absolutely nothing about the audibility of these effects at 20 kHz. Besides, for CD audio, we're talking about 22 kHz, and very few people indeed can hear that high, even when young. Still, let's say there is a slim chance that a 4-year-old with bat-like hearing might find the "ringing" displeasing. To avoid this, simply move it up to 48 kHz. There nobody can possibly hear it.

Hi,

Again, the point i was referring to is that ringing has been characterised - and the preference as given in the website.

 

If you are stating that the ringing at the higher frequencies do not correlate to the same preference at 2kHz, then ok.

 

Regards,

Shadders.