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Topic: AES 2009 Audio Myths Workshop (Read 165967 times) previous topic - next topic
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AES 2009 Audio Myths Workshop

Reply #50 –
Quote from: dwoz on
No, Ethan.  You use that section of the video to show that phase shift is ONLY AUDIBLE WHEN IT'S CHANGING, and specifically say it ISN'T when it stops changing.  YOU are taking that out of context, not me.  Oh, and you're wrong as well.  It is QUITE audible in the cello.
I took it as saying that phase change was audible only when it varies in one of the two channels, but not when it varies uniformly.

Quote
Oh, and THIS POST OF YOURS is a straw man, by it's very definition.  A classic example.  I've given plenty of examples.  I hardly think the readership here is interested in it, in this thread.  It exists, it passes peer review.

I'm not sure that you have fully grasped what a straw man argument is.

AES 2009 Audio Myths Workshop

Reply #51 –
Quote from: Tahnru on
This has the potential to generate a false negative result - not a problem.  See this old thread which I posted in for a discussion: http://www.hydrogenaudio.org/forums/index....st&p=401215

This seems to say that ABX can't be used to demonstrate transparency. The two possible outcomes for ABX are:
  • "There is supposed to exist reasonable evidence to support the idea that a difference can be noticed."
  • "This test failed to provide evidence that an audible difference existed."
The latter should not be confused with "There is supposed to exist reasonable evidence to support the idea that a difference cannnot be noticed."

So where are we? If audiophiles could just get a repeatable positive result on an ABX, they'd win outright (or more likely we'd move on to arguments about what differences are significant). But one should bear in mind that a strict reading of the "...failed to provide evidence..." outcome, no matter how many times it is reached, does not help the objectivist. With so much to gain and nothing to lose, maybe audiophiles can learn to love the ABX.

AES 2009 Audio Myths Workshop

Reply #52 –
Quote from: andy o on
Quote from: dwoz on
No, Ethan.  You use that section of the video to show that phase shift is ONLY AUDIBLE WHEN IT'S CHANGING, and specifically say it ISN'T when it stops changing.  YOU are taking that out of context, not me.  Oh, and you're wrong as well.  It is QUITE audible in the cello.
I took it as saying that phase change was audible only when it varies in one of the two channels, but not when it varies uniformly.

Quote
Oh, and THIS POST OF YOURS is a straw man, by it's very definition.  A classic example.  I've given plenty of examples.  I hardly think the readership here is interested in it, in this thread.  It exists, it passes peer review.

I'm not sure that you have fully grasped what a straw man argument is.



No, I have to disagree.  He said very specifically, to listen as the phase is changed, you can hear the familiar "phaser" effect as it moves...but when it stops CHANGING, and is in a steady-state at some other phase value, you can't hear it.  Now, I just paraphrased that, because I don't want to go back and dig up the video AGAIN. Now...if you CAN'T hear the phasing sound as it changes, you really need to be in the bleachers instead of at center court...but what I found interesting was that I could clearly hear that the sound had fundamentally changed from where it had been.  Ethan then states that the sound has not changed, and so phase CHANGE is audible but phase DIFFERENCE is not.  I beg to differ.  Definitely, the frequency/amplitude spectrum of the sound has not changed, but the spatial characteristics are wildly different.

Now, that's to me, someone who needs to pay attention to things like how much room in a soundstage a particular instrument takes up, because by gosh I have to fit 12 more in there SOMEWHERE.

To the casual listener, it isn't a salient difference.


Where mixerman was trying to go, was to introduce the concept of THE ARTIST'S STAKE.

When I listen to a bass track from Geddy or Vic or Abe...It sounds really GOOD to me, because I have no frame of reference.  When I listen to a bass part by DWOZ, well, it can have extremely subtle differences and be strikingly different.  Because I have a stake.  I played those notes.  I KNOW what my time sense is.  I know WHERE I played those notes, in time.  Slide that part by 3 ms, and it sounds completely different to me.  (I've had exactly that experience).

Change the start time of a part 3ms, that has 42 Hz tones in it?  and he HEARS that?  damn straight I do.  On my part.  NOT on Geddy's.

You folks all call yourselves "objectivists" in the audio world, as to differentiate yourselves from the audiophiles, the "subjectivists."

Well, the same thing happens in the Artist/Consumer relationship.  The artist has INTENT.  the consumer/listener....not so much.  The consumer has no real context to evaluate a musical passage...so they imprint their own, and basically ANY audio will suffice.  The artist works with intent, and when that intent isn't met, the problem, though so subtle as to be invisible to the casual observer...can result in a COMPLETELY unusable product.

and I am not talking about euphonic distortion here.

I am talking about whether the music production system has translated the INTENT of the artist, into the reproduction system.

If it has, then the artist can "like" the system.  IF it hasn't, then the artist can often tell you quite exactly why that isn't the case.

It means that CONTEXT MATTERS for the relevance and audibility of imperfections in the gear, in the system. 


An audiophile is the LAST person to notice such things.  To an audiophile, they can listen to static or white noise, and derive just as much enjoyment as listening to music...because they're not listening to music.  They're listening to music reproduction equipment.

So anyway...the point is that it is a fundamental mistake to discount CONTEXT when you talk about this stuff.  You have to know which side of the glass you're talking about.  Audiophile tomfoolery is hell-and-gone from the kind of situations you encounter, the kinds of situational effects you deal with, on the music production side.

In music REproduction, you are almost never dealing with summed signals.  In music PROduction, you are ALWAYS dealing with summed signals.  The two different systems are....well....different.

It is a fundamental mistake to conflate the two.

dwoz

AES 2009 Audio Myths Workshop

Reply #53 –
Quote from: Notat on
Quote from: Tahnru on
This has the potential to generate a false negative result - not a problem.  See this old thread which I posted in for a discussion: http://www.hydrogenaudio.org/forums/index....st&p=401215

This seems to say that ABX can't be used to demonstrate transparency. The two possible outcomes for ABX are:
  • "There is supposed to exist reasonable evidence to support the idea that a difference can be noticed."
  • "This test failed to provide evidence that an audible difference existed."
The latter should not be confused with "There is supposed to exist reasonable evidence to support the idea that a difference cannnot be noticed."

So where are we? If audiophiles could just get a repeatable positive result on an ABX, they'd win outright (or more likely we'd move on to arguments about what differences are significant). But one should bear in mind that a strict reading of the "...failed to provide evidence..." outcome, no matter how many times it is reached, does not help the objectivist. With so much to gain and nothing to lose, maybe audiophiles can learn to love the ABX.



This is my position as well.  In the great debates about audibility, if EVEN ONE respondent can reliably identify the differences, then the point is lost, as far as absolute fact is concerned.  Then, it becomes a haggle over what level of "golden ear" you have to be.  But my previous post discusses one reason that this may be significant.

AES 2009 Audio Myths Workshop

Reply #54 –
Quote from: dwoz on
The part that concerns me, is that one doesn't even have to go to tests, to disprove your conjectures.  They fall on general theory.



This looks for all the world like a totally vague, unsubstantiated claim.

I'd like to see this person who hides behind the Dwoz nym actually stop walking on the ceiling, find just one thing that was actually said in the video, not some paraprhase, and let's take this puppy apart.

AES 2009 Audio Myths Workshop

Reply #55 –
Quote from: dwoz on
In music REproduction, you are almost never dealing with summed signals.  In music PROduction, you are ALWAYS dealing with summed signals.  The two different systems are....well....different.

It is a fundamental mistake to conflate the two.


Help me here. I can't think of any situation involving music reproduction where we aren't dealing with a summed signal.  Can you give me an example?

AES 2009 Audio Myths Workshop

Reply #56 –
Quote from: dwoz link=msg=0 date=
Ethan ... makes a conjecture about the required measurements to fully and completely describe the fidelity of audio. According to him, there's four.



This is what I think is an important issue that was a few posts back from the end of the thread that this thread was split from.

Would it be possible to Ethan to repost what he origionally said about this issue?

AES 2009 Audio Myths Workshop

Reply #57 –
Quote from: Arnold B. Krueger on
Quote from: dwoz on
The part that concerns me, is that one doesn't even have to go to tests, to disprove your conjectures.  They fall on general theory.



This looks for all the world like a totally vague, unsubstantiated claim.

I'd like to see this person who hides behind the Dwoz nym actually stop walking on the ceiling, find just one thing that was actually said in the video, not some paraprhase, and let's take this puppy apart.


What on earth does that mean?  You callin' me out, girlfriend?

 


Arny, I've been reading your spouting nonsense on the internet pipes since the old days of rec.audio.pro...this is not our first meeting, by far.  Since back before you and tommy nousaine used to scratch each other's eyeballs out with sharpened faux fingernails...


Ok, let's start, shall we?  This will have "math" in it, so go find your kid and ask for his help.

Ethan "debunks" the myth that recording many different tracks through the same components will cause a "stacking up" of that component's sonic characteristic.  He says, that whatever it imparts to the individual tracks, can be COMPLETELY compensated by applying an inverse effect ONCE to the master summing buss.

This is wrong.  The effect is not a myth.  I debunked his debunk.  I felt that it would be a disservice to the kids coming up if they picked up this nonsense and started re-spewing it.

Here's what is wrong:  In order to completely compensate for the effect, he suggests that you can simply apply the inverse to the sum of all tracks.  In MATH, that implies that the transitive property applies to the sum.  in other words, if f(x) is the transfer function of the component:

~f(f(a) + f(b) + f©) = (~f(f(a)) + ~f(f(b)) + ~f(f©)).

in actuality, this statement can't be made.

In real life, f(x) is not linear.  it has a linear component, and a non-linear component:

f(x) = f.lin(x) + f.non(x)

the transitive property ONLY WORKS if f(x) is a linear function.

thus, the non-linear component, f.non(x) WILL "STACK" and WILL NOT BE REVERSED with the application of an inverse function to the sum.

Ethan will now come in here and say "what bull...he didn't DEFINE f(x)."  The rebuttal is, it is true for ANY non-linear f(x).

Therefore, the MATH decisively shows that stacking of non-linearities WILL OCCUR and CANNOT be compensated for at the mix buss.

This is simple math.  I didn't invent it.  glad to help you.

Not a "vague, unsubstantiated claim".  Simple math.  No need to progress to listening tests.

Not to put too fine a point on it, but reading the advice you give to people around here, I'm not concerned about being refuted, though I'd LOVE to be proved wrong.

AES 2009 Audio Myths Workshop

Reply #58 –
Quote from: Arnold B. Krueger on
Quote from: dwoz on
In music REproduction, you are almost never dealing with summed signals.  In music PROduction, you are ALWAYS dealing with summed signals.  The two different systems are....well....different.

It is a fundamental mistake to conflate the two.


Help me here. I can't think of any situation involving music reproduction where we aren't dealing with a summed signal.  Can you give me an example?



easy.  put a CD in your favorite CD player, turn up the volume, and sit in your chair.  You are now listening to two discrete reproduced signals coming out of two speakers.  No electrical summing whatsoever.

That describes the music REPRODUCTION system, as contrasted with the music PRODUCTION system.

Never mind live music rigs...that's so far hell-and-gone from any kind of fidelity, it isn't worth wasting breath on.

AES 2009 Audio Myths Workshop

Reply #59 –
Quote from: dwoz on
~f(f(a) + f(b) + f©) = (~f(f(a)) + ~f(f(b)) + ~f(f©)).

in actuality, this statement can't be made.

In real life, f(x) is not linear.  it has a linear component, and a non-linear component:

f(x) = f.lin(x) + f.non(x)

the transitive property ONLY WORKS if f(x) is a linear function.

thus, the non-linear component, f.non(x) WILL "STACK" and WILL NOT BE REVERSED with the application of an inverse function to the sum.


The intransitivity of f.non(x) does not imply that there isn't a function g(f(a)+f(b)+f©) = ~(f(a)+f(b)+f©). If you wan't to show off high school math skills, do it right. All I have seen from you, since you have registered here, is mis-quoting, chest thumping, and half-cooked knowledge. Despite your scampered frequency of posting, you couldn't, yet, make a single conclusive point against Ethan. This wouldn't be so bad, if you had the mental capacity to actually read and relate your own words to others'. But obviously your skills are somewhat binary in the sense that your brain just attaches a "correct"-tag to anything coming from inside, which seems to prevent any further processing.

Quote from: dwoz on
Ethan "debunks" the myth that recording many different tracks through the same components will cause a "stacking up" of that component's sonic characteristic.  He says, that whatever it imparts to the individual tracks, can be COMPLETELY compensated by applying an inverse effect ONCE to the master summing buss.


You must have another version of the film playing in your head. Could you quote the position, where Ethan (or anyone else) would say "COMPLETELY", by the way? I think that's not to much to ask for something, you are so sure about, that you cite it in caps.

AES 2009 Audio Myths Workshop

Reply #60 –
Quote from: googlebot on
Quote from: dwoz on
~f(f(a) + f(b) + f©) = (~f(f(a)) + ~f(f(b)) + ~f(f©)).

in actuality, this statement can't be made.

In real life, f(x) is not linear.  it has a linear component, and a non-linear component:

f(x) = f.lin(x) + f.non(x)

the transitive property ONLY WORKS if f(x) is a linear function.

thus, the non-linear component, f.non(x) WILL "STACK" and WILL NOT BE REVERSED with the application of an inverse function to the sum.


The intransitivity of f.non(x) does not imply that there isn't a function g(f(a)+f(b)+f©) = ~(f(a)+f(b)+f©). If you wan't to show off high school math skills, do it right. All I have seen from you, since you have registered here, is mis-quoting, chest thumping, and half-cooked knowledge. Despite your scampered frequency of posting, you couldn't, yet, make a single conclusive point against Ethan. This wouldn't be so bad, if you had the mental capacity to actually read and relate your own words to others'. But obviously your skills are somewhat binary in the sense that your brain just attaches a "correct"-tag to anything coming from inside, which seems to prevent any further processing.

Quote from: dwoz on
Ethan "debunks" the myth that recording many different tracks through the same components will cause a "stacking up" of that component's sonic characteristic.  He says, that whatever it imparts to the individual tracks, can be COMPLETELY compensated by applying an inverse effect ONCE to the master summing buss.


You must have another version of the film playing in your head. Could you quote the position, where Ethan (or anyone else) would say "COMPLETELY", by the way? I think that's not to much to ask for something, you are so sure about, that you cite it in caps.


High school math?  quite true.  Then why do you have it wrong?  OBVIOUSLY there is a function g(x) as you describe.  It just isn't ~f(x).  That's reading for comprehension.  It's also quite rude.  You haven't even seen the video have you?  Clearly not. because Ethan does indeed use the word "completely".  Unless, of course, he's edited it since.

Look, if you guys want, go ahead and carry this guy around on your shoulders.  Good on ya.  Everyone got to have a hero.  Everyone can't  be on the winning team, after all. 

Good luck, and godspeed.

AES 2009 Audio Myths Workshop

Reply #61 –
Quote from: Mixerman on
Well since my last post was moved to a read only section as a "baiting" post, which it wasn't intended as, then let me rephrase the question:

How many of you here in this thread, discussing the debate we've had with Ethan, have actually mixed a full album?

Anyone?

Mixerman


Being a good audio mixer doesn't immunize you from the psychological biases that make blind testing or objective data requirements to scientifically verify claims of audible difference.

Liked your book, btw.

AES 2009 Audio Myths Workshop

Reply #62 –
Quote from: dwoz on
Lacking controls for cohort competence would seem to me be grounds to invalidate a negative assumption from the test, wouldn't it?  Particularly when the result is being expressed POSITIVELY, i.e. instead of "no respondents could positively identify...." instead the result is expressed as "differences are not audible"?


First, the result of an ABX should not be expressed that way in a report using scientific language.  The result is properly expressed as something like, 'audible difference was not supported (at the level of statistical significance chosen)'.

*If* a subject says he hears a difference in sighted trials, and also during the ABX test itself, but the ABX results do not support that claim, it would seem that the test itself was not obscuring the subjective perception of difference prima facie and that the ABX is sufficient to demonstrate whether or not the difference heard during teh ABX was likely to be 'real' or not.  However positive controls are an excellent practice and full rigor requires employing them.  Certainly if the subject *claims* to hear no difference  (or claims to have trouble hearing a difference) during the ABX, a positive control must be introduced to establish at what level difference CAN be heard.

 








AES 2009 Audio Myths Workshop

Reply #63 –
Quote from: Synthetic Soul on
Quote from: Arnold B. Krueger on
Quote
Ok, let's start, shall we?  This will have "math" in it, so go find your kid and ask for his help.
Which kid should I ask, Dwoz? The boy with a PhD, the girl with a PhD, or the dumb one with just a degree in Chemical engineering and a MBA? Oh, and a dual major in Environmental Engineering. Which one should I ask Dwoz? Do you even have any kids who graduated from High School? Did you ever have a stable relationship that lasted long enough so that you raised any kids at all? Does sex the way you like it even ever make kids? ;-)
As somebody who has no interest in these threads I am more than happy to just close it, if people can't play nice.  There's a lot of petty name calling that I'm willing to ignore, but this has gone past that.

Play nice, or don't play at all. I really don't care either way.


Dwoz apparently thinks he can scare people away with tough talk.

I'm trying to return things to our regular programming.

I finally have some *original words of Ethan* posted.

Anyway, it appears that these are among the statements that Ethan *actually made* and should be defending. note that they are stated in such a way that he's debunking the following misapprehensions:

* That dither is audible on typical program material recorded at sensible levels.

* That jitter is ever audible in non-broken gear.

* That a response past 20 KHz is ever needed.

* That blind testing is not valid.

* That static (non-changing) phase shift in usual amounts is ever audible when the amount of shift is the same left and right.

* That more than four parameters are needed to describe everything that affects audio reproduction.

* That different gear that specs "transparently" as defined in my video has a sound, or sounds different than other transparent gear.

* That prosumer level sound cards cannot achieve professional sounding results.

* That audible stacking occurs with properly functioning gear.

End of list of misapprehesions that Ethan is trying to correct.


Here's what Ethan said on the womb about ADAT versus analog tape:

"I had dinner the other night with a good friend who is a fairly well known recording engineer with a wall full of gold records in his studio lobby. He told me that when ADATs came out - the original black-face model - he did a comparison of analog 2-inch versus ADAT, and the ADAT won handily because it preserved drum transients much better. That matches my experience, but I asked him to repeat what he said anyway to be sure I didn't misunderstand. I figured it would come up here eventually. I won't say who he is here without his permission, though I can't imagine he'd really mind. If you're reading this Peter you are welcome to pipe up to clarify."

So far, I see more than a few differences between what Ethan is purported to have said, and what he actually said. Some similarities as well.

AES 2009 Audio Myths Workshop

Reply #64 –
Quote from: dwoz on
High school math?  quite true.  Then why do you have it wrong?  OBVIOUSLY there is a function g(x) as you describe.  It just isn't ~f(x).  That's reading for comprehension.


So, if there "OBVIOUSLY" is a inverse function, how is your math example in any way applicable to the matter at hand? Ethan did not claim anything about the mathematic nature of inverse filtering. Your transitivity example just disproves that part, which you had made up by yourself and falsely put into Ethan's mouth.

1.) The existence of g(x) proves that transitivity, which you put on the table, doesn't matter relating to the question, wether a series f(a)...f(b)...f© can be reversed in a single step.
2.) Ethan did not claim transitivity of f(x).

So, it seems to be the case, that the function of your math example was plainly rhetorical and even failed at that.

AES 2009 Audio Myths Workshop

Reply #65 –
Quote from: dwoz on
one doesn't even have to go to tests, to disprove your conjectures.

Yet another post saying "Ethan is wrong" without evidence and without saying what is right.

Quote from: dwoz on
He said very specifically, to listen as the phase is changed, you can hear the familiar "phaser" effect as it moves...but when it stops CHANGING, and is in a steady-state at some other phase value, you can't hear it.

You really need to watch my video again. The "phaser" effect is comb filtering, and that is audible whether it's static or changing.

Am I the only person who has noticed that not one of the nay-sayers has presented a single audio example to prove their point? All they do is try to tear down all of the examples in my video, and call me wrong, but never once have they shown their own example and said what's right.

Dwoz, please post some audio files showing that dither is audible on pop music recorded at sensible levels. Please post an example showing when jitter is audible. Please show us that phase shift can be heard. Please prove with an audio file that stacking is not a myth. And so forth.

If you can't do that, then perhaps you need to change your opinions.

--Ethan
I believe in Truth, Justice, and the Scientific Method

AES 2009 Audio Myths Workshop

Reply #66 –
Quote from: Arnold B. Krueger on
I'd like to see this person who hides behind the Dwoz nym actually stop walking on the ceiling, find just one thing that was actually said in the video, not some paraprhase, and let's take this puppy apart.

Indeed. Attacking people while hiding behind an anonymous screen name is the height of dishonesty.

What I don't understand is why dwoz and Mixerman and malice are so interested in discussing this everywhere they can. If they think I'm a crackpot, why don't they just ignore me instead of "promoting" me with four threads on their forum and even a custom graphic? They're not content to write more than one thousand posts in their own forum, but they also post about my video at Gearslutz and now here too. I've been emailing Mixerman trying to arrange a "truce" whereby he'd let me post freely in his forum. It's not getting anywhere lately. Here's my last question to him, which he seems unable to answer:
[blockquote]"If you think I'm incompetent and disingenuous and giving out bad
advice, why do you even want me posting in your forum at all?"[/blockquote]
--Ethan
I believe in Truth, Justice, and the Scientific Method
 

AES 2009 Audio Myths Workshop

Reply #67 –
It's really sad, to see such a nice guy on a honorable mission getting mobbed by anonymous lunatics. You don't deserve that. Why are you doing it at all, if I may ask? Why don't you stick to more level-headed grounds as Hydrogenaudio?

I'm also hiding cowardly behind an anonymous nickname. But for me it makes sense. With billions of people out there, many of them at the edge of sanity, I just don't want to risk my real name getting dragged through the mire by some random anonymous idiot. Not everyone googling my name will find the time to read several pages of arguments until I can shut off a jerk. And I don't even want to be in a position where I would have to do that, to keep my name clear.

AES 2009 Audio Myths Workshop

Reply #68 –
Quote from: googlebot on
It's really sad, to see such a nice guy on a honorable mission getting mobbed by anonymous lunatics. You don't deserve that. Why are you doing it at all, if I may ask? Why don't you stick to more level-headed grounds as Hydrogenaudio?

Yes, it's sad and pathetic even. Especially the anonymous part. They need to grow a pair and use their real names, and be responsible for their opinions.

The reason I made this video, and write many articles, and post on many forums, is very simple - to educate. Consumerism is equally important to me. Guys like these from the Womb, and Audio Asylum, and Stereophile's forum will not be swayed no matter how compelling the evidence. As we see here. But I don't do this to convince them because that's futile. Rather, I write for the scores of people who every day ask in forums what preamp or converter etc they should buy to take their projects to the next level.

After years of non-science and even anti-science BS in audio magazines (home recording magazines too, not just audiophoole rags), many home recordists wrongly believe they'll never get pro results until they invest large sums into expensive and boutique outboard gear. This simply is not true. I'm not necessarily suggesting that all people need is a $25 SoundBlaster, but they certainly don't need to spend $1,000 per channel on preamps and converter to get outstanding quality. Same for hi-fi types who genuinely want to know if they need to spend large sums on cables etc.

--Ethan
I believe in Truth, Justice, and the Scientific Method

AES 2009 Audio Myths Workshop

Reply #69 –
Since it's hard to cite where something has not been said, please start by telling which position in the video you are talking about. I don't see much sense in taking your "arguments" serious, since they attack something that hasn't even been claimed by Ethan. You can easily refute this by telling the position in the video you are talking about. Else this discussion doesn't make much sense.

AES 2009 Audio Myths Workshop

Reply #70 –
Quote from: googlebot on
2.) Ethan did not claim transitivity of f(x).

So, it seems to be the case, that the function of your math example was plainly rhetorical and even failed at that.


But he did!

He said, and please don't shoot me for NOT taking the time to fetch that video and watch it AGAIN...that "if there WAS a buildup or stacking effect from a component, then you could simply apply an inverse of the component's affect, to the main mix buss (2-buss), and remove ALL of it."

Again, that was a paraphrase, but this was his exact meaning and intent.  This implies the math statement I made up-thread.  If you don't agree that this implies a transitive application, then I invite you to supply what you think the equation from the above sentence SHOULD be.  I'm happy to discuss the merits of it.

dwoz

AES 2009 Audio Myths Workshop

Reply #71 –
Quote from: dwoz on
Did you have anything to say about the math itself, Arny?  Did you see where I was going, where you'd have to be able to apply the inverse function to the summed signal, and have that be the exact same thing as applying it to the source tracks individually?  That's how the mathematical "sentence" is constructed from Ethan's dialog. I wonder if you felt that was rigorous or not, and what I'd have to do to improve it?


I've been recording a music festival for the last 2 days, out of town. There was a hot spot on premises but it had the firewall from #&!!, and wouldn't let me access any forums.

But, I'm back. ;-)

As far as the math goes, I thought that the question had been answered a few times already, and very well. Mr. Dwoz you have already been had by far better than I. But you apparently can't understand what those other said or you would have already slunk out of here with your tail between your legs.  You seem want me to put my spin on it. So, here we go, yet another nail in your coffin!

Yes Dwoz, in high school you learned what you posted. Unfortunately, you apparently didn't take any univeristy engineering courses that cover the same topic and add a more practical real world perspective.

Let me quote you exactly Dwoz:

Quote from: dwoz link=msg=0 date=
Here's what is wrong: In order to completely compensate for the effect, he suggests that you can simply apply the inverse to the sum of all tracks. In MATH, that implies that the transitive property applies to the sum. in other words, if f(x) is the transfer function of the component:

~f(f(a) + f(b) + f©) = (~f(f(a)) + ~f(f(b)) + ~f(f©)).

in actuality, this statement can't be made.

In real life, f(x) is not linear. it has a linear component, and a non-linear component:

f(x) = f.lin(x) + f.non(x)
Here's what is wrong: In order to completely compensate for the effect, he suggests that you can simply apply the inverse to the sum of all tracks. In MATH, that implies that the transitive property applies to the sum. in other words, if f(x) is the transfer function of the component:

~f(f(a) + f(b) + f©) = (~f(f(a)) + ~f(f(b)) + ~f(f©)).

in actuality, this statement can't be made.

In real life, f(x) is not linear. it has a linear component, and a non-linear component:

f(x) = f.lin(x) + f.non(x)

the transitive property ONLY WORKS if f(x) is a linear function


Now I'll quote the statement that Ethan made that you mistakenly think you proved false:

Quote from: ethan link=msg=0 date=
* That audible stacking occurs with properly functioning gear.


Now I'll focus on what you said that is irrelevant to what Ethan said:

Quote from: dwoz link=msg=0 date=
In real life, f(x) is not linear. it has a linear component, and a non-linear component:

f(x) = f.lin(x) + f.non(x)


In Ethan's "properly functioning" gear,  your equation

Quote from: dwoz link=msg=0 date=
f(x) = f.lin(x) + f.non(x)


Can be filled in with some real world numbers for properly functioning gear.

f(x) = 1.0 * f.lin(x) + < 0.0001 * f.non(x)

IOW, the properly functioning good quality mixers that most of us use have less than  0.01%  of any and all kinds of nonlinear distortion.  In this day and age, even Soundblaster cards and cheap Behringeri mixers have less than 0.01% THD.

My 02R96 is actually theoretically and practically distortionless as long as I don't operate  it outside the digital domain. ;-)

Therefore it is safe to ignore the tiny real world nonlinearity that you have staked your argument on.  Ethan put in the necessary hedge words to include that tiny amount of nonlinearity that it is safe to ignore.

So, the real world version of your equation reduces to: f(x) = f.lin(x).

Therefore  Dwoz, you didn't find an error in what Ehtan wrote. You changed what Ethan wrote into something of your own creation by dropping out some key words, and then used a theorectical argument that is irrelevant to the real world of 2010.

Quote from: ethan link=msg=0 date=
* That audible stacking occurs with properly functioning gear.


The key words that Dwoz left out are:

audible
properly
funtioning

IOW, aobut half of what Ethan said.

There's a reason you don't post under your real name "Dwoz" - when you get caught short like this it doesn't have any consquences. If you trash the rep of the nym Dwoz enough with dumb mistakes like these, you just pop up with a new nym.









AES 2009 Audio Myths Workshop

Reply #72 –
No...I've never felt the need to use sock puppets.  The only time I ever use a sock puppet user account, is to test my own forum, so I can see what a regular user sees and test user and group permissions.  But I never post with that handle.

The thing is, it's ALL ABOUT those "key words".  When you make the declarations that Ethan's made, there is a perceived "truth" there.  People hear the absolute statements about things like "stacking".  They MISS the quick "weasel words" that equivocate the point. 

Yes, "weasel words" is a pejorative. They are exactly the kinds of words that the audiophile crazies use.  They must be avoided like bubonic plague.

So, Ethan makes his point, then throws the red meat back into the trash, by uttering equivocation about "for all intents and purposes" and "audible" and such.

My point is this:  Stacking, as a matter of absolute fact, does indeed exist,and cannot be completely remedied by functions applied to later summed artifacts of the process.    Then, it is a second, and perhaps just as important fact, to acknowledge that this stuff is something you'll have to work to make audible. 

Like recording 75 tracks of dialog on the same preamp and mic, along with 25 tracks of foley and another 20 of ambience.  Do you think it's outlandish that a film post mixer will have upwards of 125 tracks at once?  It isn't.  That user needs to worry about "stacking" and he is done a disservice if he thinks it doesn't exist at all.

It is SO IMPORTANT to be careful when you talk about this stuff!  Ethan makes his point, then throws it away by qualifying it!  He needs to NOT do this, and his video will be so much stronger!  Saying "using today's gear" is DAMAGING to his point, but he won't see that.  Instead of using the equivocation, he needs to talk about just when the thresholds will BECOME audible.  Like my friend the film post mixer... then his audience can make the judgment on their own.  Otherwise, they eventually hear the effect, in some deranged special case, and instead of saying "Ethan was right, and here's the threshold of audibility!" they will INSTEAD say "Ethan was WRONG!".

Isn't this all about actually using rigorous science to prove things?


dwoz

AES 2009 Audio Myths Workshop

Reply #73 –


Just to clarify:

Ethan's conjecture is that the stacking of component characteristic is a myth, because it can be simply eliminated by applying a single inverse "value" of the characteristic, to the summed master.

In this definition, he elaborates by saying that if a component put a 3dB 'bump' at a certain frequency, and you used that component on 10 tracks, then you don't need to remove 30dB of "bump" from the master, but only 3dB.  So far so good.  But then he pollutes this by saying that you can completely compensate using one 3dB inverse function. 

That's the rub!  you can NOT completely compensate!  Because it's non-linear!!!!!

Also, it isn't just frequency and amplitude where f(x) can manifest.  Imagine that you have a component that acts as an all-pass, but has a non-linear phase response.  Stack those puppies up and try to apply an inverse.  Not gonna happen!

the important thing here is the realize that you must be EXTREMELY careful how you generalize a statement.  You can take a perfectly true fact, and make it false by applying it too broadly.

dwoz

AES 2009 Audio Myths Workshop

Reply #74 –
Quote from: dwoz on
Ethan's conjecture is that the stacking of component characteristic is a myth, because it can be simply eliminated by applying a single inverse "value" of the characteristic, to the summed master.

In this definition, he elaborates by saying that if a component put a 3dB 'bump' at a certain frequency, and you used that component on 10 tracks, then you don't need to remove 30dB of "bump" from the master, but only 3dB.  So far so good.  But then he pollutes this by saying that you can completely compensate using one 3dB inverse function. 

That's the rub!  you can NOT completely compensate!  Because it's non-linear!!!!!


I don't follow here.  If you have a summer with N inputs, and the identical linear filter in each of the N paths leading to the summer, then barring nonlinearity you can (conceptually) move that linear filter after the summer.  This assumes no limiters. compressors, clipping op-amps or other grossly nonlinear devices in the chain between any of these filters and their corresponding input to the summer.  If that linear filter is minimum-phase, then its inverse is stable and you can correct for the filter's inclusion with a single filter at the summer output that implements the reciprocal of the transfer function of the original filter.

Quote from: dwoz on
Also, it isn't just frequency and amplitude where f(x) can manifest.  Imagine that you have a component that acts as an all-pass, but has a non-linear phase response.  Stack those puppies up and try to apply an inverse.  Not gonna happen!


The issue there is that analog all-pass filters are non-minimum phase devices, so their inverse is unstable.  That's why you can't in general compensate for their effects in an exact way.

Quote from: dwoz on
the important thing here is the realize that you must be EXTREMELY careful how you generalize a statement.  You can take a perfectly true fact, and make it false by applying it too broadly.


This points out the need to qualify one's statements.  As above, the filter must be linear and minimum-phase and all the components in each path from the filter to the summer must be linear for the correction to work.  So generalizing is not always possible.  Yet you're also getting on Ethan's case for qualifying his statements.  You're telling him, in effect, that he shouldn't qualify his statements, nor should he generalize them.