MQA is Vaporware

[manisandher]

3 minutes ago, Shadders said:

Yes - really...

 

If you say so.

 

Mani.

[Lee Scoggins]

9 hours ago, Don Hills said:

Looks like Lee has taken his ball and gone home over on SH?

 

I honestly don’t know what happened. I dropped off around 9pm last night to watch a movie, then this morning could not find the thread.  I saw some comments from Agitater that people had hurled some personal epithets at me.  I am bummed because they gorts usually just remove the offensive posts and give a public warning.  Now we don’t have access to the articles, etc.

[adamdea]

Another day another rabbit hole.

[Shadders]

1 minute ago, manisandher said:

 

If you say so.

 

Mani.

Hi,

Well, yes - it is in black and white on page 290.

If you go to the page and scroll down you will see that you asked :

 

"Maybe I'm really dense, but I'm find this confusing. Aliasing occurs during analogue-to-digital conversion, and not during digital-to-analogue conversion, and yet he talks about using an anti-alias filter in a DAC. Are the terms 'aliasing' and 'imaging' really so interchangeable? "

Regards,

Shadders.

[Andyman]

6 minutes ago, Shadders said:

Hi,

Yes - really - see the original post by yourself questioning whether imaging and aliasing are interchangeable.

Regards,

Shadders.

 

Hi Shadders.

I suspect Mani's original question was rhetorical. You're getting yourself into trouble here and starting to pick fights with people who clearly understand better than you. As Adamdea suggested a while back, maybe you need to take a breath. You obviously have a grasp of this subject but you should also be aware of what you don't know. If you get something wrong, hold your hands up . No biggy. Or you just end up digging a bigger hole. I'm not the police, just a friendly suggestion.

Thanks and regards ()

Andy

[Fokus]

1 hour ago, Shadders said:

When the image frequencies overlap the baseband frequencies - it is called aliasing.

 

There is indeed a particular graphical representation that gives rise to the above.

A bit like this

 

 

The reasoning is as follows:

 

Consider a signal with spectrum S. This signal is not sampled, but you are going to sample it with Fs.

Before sampling, draw the spectrum S, together with all of its images about Fs/2.

 

Any portion of the first image that extends below Fs/2 will end up as an alias after sampling.

 

 

Of course this is not a justification for using 'aliasing' and 'imaging' interchangeably. Images are the result of expanding a sampled signal space (the unit circle) to an infinite linear space (or at least a larger circle). This is about representation. Aliases are the result of an error, a distortion.

 

 

(And then there is Paul Miller of HFN who names images 'aliasing images', which can 'fold into the audible band when hitting a bad tweeter'...)

 

[Shadders]

17 minutes ago, Andyman said:

 

Hi Shadders.

I suspect Mani's original question was rhetorical. You're getting yourself into trouble here and starting to pick fights with people who clearly understand better than you. As Adamdea suggested a while back, maybe you need to take a breath. You obviously have a grasp of this subject but you should also be aware of what you don't know. If you get something wrong, hold your hands up . No biggy. Or you just end up digging a bigger hole. I'm not the police, just a friendly suggestion.

Thanks and regards ()

Andy

Hi,

I will challenge people who make false claims about myself. Just because people have 2 degrees (as an example), doesn't make them right, and they can then make defamatory statements.

I am happy to be educated - once they provide proof.

Regards,

Shadders.

[Shadders]

4 minutes ago, Fokus said:

 

There is indeed a particular graphical representation that gives rise to the above.

A bit like this

 

 

The reasoning is as follows:

 

Consider a signal with spectrum S. This signal is not sampled, but you are going to sample it with Fs.

Before sampling, draw the spectrum S, together with all of its images about Fs/2.

 

Any portion of the first image that extends below Fs/2 will end up as an alias after sampling.

 

 

Of course this is not a justification for using 'aliasing' and 'imaging' interchangeably. Images are the result of expanding a sampled signal space (the unit circle) to an infinite linear space (or at least a larger circle). This is about representation. Aliases are the result of an error, a distortion.

 

 

(And then there is Paul Miller of HFN who names images 'aliasing images', which can 'fold into the audible band when hitting a bad tweeter'...)

 

Hi Fokus,

Thanks. I am aware that the image statement means the baseband signal replicated at a. n. other sample frequency, and aliasing is the effect of the two signals overlapping.

Regards,

Shadders.

[Lee Scoggins]

9 hours ago, tmtomh said:

Holy moly - can't believe they nuked the entire thread! It was enormous. That sucks.

 

I'm absolutely not one of those unquestioning Hoffman acolytes. But I will say that Hoffman did post in the MQA thread saying he has no interest in MQA. And the thread didn't get nuked despite pages and pages and pages of comments disparaging not only Lee Scoggins, but also Bob Stuart.

It could be a coincidence, the the one new thing that happened today was that Lee made disparaging remarks about a deceased audio guy (I think with Ayre? Sorry, I can't remember), and that triggered a firestorm. That probably was the straw the broke the camel's back - although deleting the whole thread seems draconian to me.

 

I find it draconian as well.  Hopefully the Gorts just moved it to their discussion forum to clean it up.  Although it was contentious at times, there was some good information there from both sides of the coin.  And the discussion was civil at times between some of the participants.

 

Perhaps I could have worded my comment about Hansen better but there has been a lot of dismay about Hansen.  It would have been nice to interview him before he passed.

[Lee Scoggins]

10 hours ago, Indydan said:

 

If you're saying the Brooklyn is as good or better than the Ayre QB9 DSD, or even the Codex, you just lost all credibility (assuming you had any). 

 

And Charles Hansen said things about Bob Stuart that unless proven otherwise, were true. If Stuart looks douchey, it is because of his actions (lying about opamps in his gear, trying to steal a design from John Curl). Don't shoot the messenger Hansen. 

 

I have heard good stories from people in the business about Charles Hansen. I won't get preachy about it, but he was known for caring about his employees and conducting business in a very ethical manner. 

 

To make negative comments about him like you have, is just classless. 

 

Of course, there was no reference to the QB9 DSD in my comments. I have not done that comparison.

[manisandher]

Just for my understanding...

 

Are those of you who are critical of the filters MQA uses critical of:

 

a) the anti-aliasing filter used in the MQA encoder?

b) the anti-imaging filter used in an MQA renderer?

c) both?

 

If you could substantiate your answer (edit: or point me to links), that'd be great.

 

Mani.

[Samuel T Cogley]

11 minutes ago, Lee Scoggins said:

 

I honestly don’t know what happened. I dropped off around 9pm last night to watch a movie, then this morning could not find the thread.  I saw some comments from Agitater that people had hurled some personal epithets at me.  I am bummed because they gorts usually just remove the offensive posts and give a public warning.  Now we don’t have access to the articles, etc.

 

Nice try Lee.  There were no epithets that I saw on that thread.  Hoffman likely had it deleted because it reflected poorly on MQA and their surrogates (i.e., you).  When you posted that despicable stuff about Charlie Hansen, you basically made Hoffman look as  despicable as you.  He had no choice.  There's a reason only Hoffman himself (and no gorts) was in that thread scolding your skeptics.

 

Look at the bright side.  Hoffman did you a favor by deleting that post of you proclaiming that "prominent audio leaders" had "lost respect" for Hansen.  It would be fascinating to poll those same "prominent audio leaders" for their opinion of you.  I suspect you might be unpleasantly surprised.

 

Looking forward to the next MQA marketing "article" on PTA.  No doubt it will be as much fun as the last one. 

 

[testikoff]

MQA must be using the same filter in both downsampling (preceding folding) & upsampling (rendering) stages:

 

A 30kHz spike on MQA decoded+rendered track is an alias of 58kHz spike on DXD source. Two ~50kHz spikes on MQA decoded+rendered track are images of two ~38kHz spikes on both DXD source & MQA-decoded (24/88) version.

[Fair Hedon]

18 minutes ago, Samuel T Cogley said:

 

Nice try Lee.  There were no epithets that I saw on that thread.  Hoffman likely had it deleted because it reflected poorly on MQA and their surrogates (i.e., you).  When you posted that despicable stuff about Charlie Hansen, you basically made Hoffman look as  despicable as you.  He had no choice.  There's a reason only Hoffman himself (and no gorts) was in that thread scolding your skeptics.

 

Look at the bright side.  Hoffman did you a favor by deleting that post of you proclaiming that "prominent audio leaders" had "lost respect" for Hansen.  It would be fascinating to poll those same "prominent audio leaders" for their opinion of you.  I suspect you might be unpleasantly surprised.

 

Looking forward to the next MQA marketing "article" on PTA.  No doubt it will be as much fun as the last one. 

 

Familiar pattern.

 

He posts ignorant drivel, then tries to back track an spin. We have seen this dozens of times.

[Fair Hedon]

29 minutes ago, Lee Scoggins said:

 

I find it draconian as well.  Hopefully the Gorts just moved it to their discussion forum to clean it up.  Although it was contentious at times, there was some good information there from both sides of the coin.  And the discussion was civil at times between some of the participants.

 

Perhaps I could have worded my comment about Hansen better but there has been a lot of dismay about Hansen.  It would have been nice to interview him before he passed.

No, sorry, you don't get off that easy.

 

You show clear signs of sociopathic behaviour. Or you suffer from sever Aspergers.  Or Both.

 

Many of the posters here are going to make sure PTA sees all your wonderful posting history.

[manisandher]

15 minutes ago, testikoff said:

MQA must be using the same filter in both downsampling (preceding folding) & upsampling (rendering) stages:

 

Thanks. I can see exactly what you're explaining.

 

The use of such filters must have been a deliberate choice made by the MQA guys. Is there any evidence that using 'leaky' AA and AI filters is offset by gains in the temporal domain?

 

Mani.

[mansr]

Just now, manisandher said:

Is there any evidence that using 'leaky' AA and AI filters is offset by gains in the temporal domain?

Define "gains in the temporal domain." Bear in mind that the ear is fundamentally a frequency detector.

[christopher3393]

9 minutes ago, Fair Hedon said:

No, sorry, you don't get off that easy.

 

You show clear signs of sociopathic behaviour. Or you suffer from sever Aspergers.  Or Both.

 

Many of the posters here are going to make sure PTA sees all your wonderful posting history.

 

Looks like you see Lee's post on Charles Hansen as a personal attack on a well respected, recently deceased industry pro. I understand that but don't agree it has to be read that way.

 

Regardless, you've made yet another personal attack, one of many. You know very well that Chris C. has stated that personal attacks are not tolerated here. He has stated this numerous times. He has also warned you at least twice.

 

Either your continued personal attacks should not be tolerated, or a reason for you being an exception to the rules at CA should be presented.

[The Computer Audiophile]

18 minutes ago, Fair Hedon said:

No, sorry, you don't get off that easy.

 

You show clear signs of sociopathic behaviour. Or you suffer from sever Aspergers.  Or Both.

 

Many of the posters here are going to make sure PTA sees all your wonderful posting history.

OK Hedon - This is your last warning. Your personal attacks and insults are over the top. One more time and you're banned.

[manisandher]

6 minutes ago, mansr said:

Define "gains in the temporal domain."

 

I left it ambiguous purposely, to keep the scope open.

 

6 minutes ago, mansr said:

Bear in mind that the ear is fundamentally a frequency detector.

 

OK, you probably won't like this. From Stuart's Munich talk:

 

"Time is 5-13x times more important than frequency. Human discriminate acuity 5–8 µs."

 

[No, I don't know what "human discriminate acuity" is either ;-) ]

 

Mani.

[Lee Scoggins]

1 minute ago, manisandher said:

 

I left it ambiguous purposely, to keep the scope open.

 

 

OK, you probably won't like this. From Stuart's Munich talk:

 

"Time is 5-13x times more important than frequency. Human discriminate acuity 5–8 µs."

 

[No, I don't know what "human discriminate acuity" is either ;-) ]

 

Mani.

 

I recently visited Dave Wilson in Provo and he also showed me research on the ear’s ability to hear timing differences which he used to design the Chronosonic flagship. He was excited about it because this ability of the ear to hear tiny timing differences holds true into one’s 70s.

[mansr]

2 minutes ago, manisandher said:

OK, you probably won't like this. From Stuart's Munich talk:

 

"Time is 5-13x times more important than frequency. Human discriminate acuity 5–8 µs."

 

[No, I don't know what "human discriminate acuity" is either ;-) ]

A badly tuned piano sounds dreadful no matter how perfectly it is played.

[Fair Hedon]

15 minutes ago, The Computer Audiophile said:

OK Hedon - This is your last warning. Your personal attacks and insults are over the top. One more time and you're banned.

Noted.

 

Thanks for the courtesy.

[manisandher]

6 minutes ago, mansr said:

A badly tuned piano sounds dreadful no matter how perfectly it is played.

 

Yes, but surely better than a perfectly tuned piano played badly.

 

Mani

[Fair Hedon]

20 minutes ago, christopher3393 said:

 

Looks like you see Lee's post on Charles Hansen as a personal attack on a well respected, recently deceased industry pro. I understand that but don't agree it has to be read that way.

 

Regardless, you've made yet another personal attack, one of many. You know very well that Chris C. has stated that personal attacks are not tolerated here. He has stated this numerous times. He has also warned you at least twice.

 

Either your continued personal attacks should not be tolerated, or a reason for you being an exception to the rules at CA should be presented.

Who made you a moderator?