[B] NEED HELP - Diganosing audio differences between source components [/B] - Page 4

So which two are broken?

Do tell what your comparison methodology was?

Maybe one is for rock, one for jazz and one for hip-hop.

One is also a BD player, used for... well, movies. One is a dedicated 2-channel player. The other is an older DVD player which is also cd/SACD capable (which has been relegated to the living room.)

Before settling on the Playback Designs for 2-channel, I also had both the Luxman D-05, and D-06. The Luxman's not only sounded different from the previous mentioned players, but sounded different from each other as well.

The absence of an answer to my question about test procedures in a timely fashion, together with your other reply probably tells part of the story.

The rest of the story would probably be laid out for you in big, bold letters if I set all 6 players up with the same CD, matched levels and established the necessary levels of time synchronization... ;-)

If the level of evidence you accept for audio judgements and indictments was allowed in the court system, the jails would likely be full of innocent people. As things stand, your house is likely full of innocent music players. Big difference in the severity of the consequences, little difference in the lack of logic.

I'm wondering how many times I am going to be temped to rebut this obvious false claim?

I am familiar with nobody who currently says that there are no measurable differences between digitial transports, except maybe people who seem to like to pose straw men, drag out stinky old red herrings, or just plain troll. ;-)

Einstein said that insanity is doing the same thing over and over again, expecting a different result. Amir, how many times are you going to do this very same thing over and over again?

Well, you and I are not situated the same then as I know many who doubt such differences exist. Here is the OP from this thread:


"Identical" in my book means they measure the same. I provided him with my article and he said: "Thanks for the link.... learning more and more every time I come here." So clearly a misunderstanding was corrected.

And he is not alone. I bet vast majority of people think that. It simply is counter-intuitive that a digital system would behave in a non-deterministic manner this way. We are all used to copying files around on our computers and having no bits lost even when we use things like a USB drive with a cable in the middle. So it is natural for people to assume digital transports would act the same.

My article on digital audio variability and jitter was originally published in Widescreen Review magazine. In 3-4 years of writing articles for them, none have generated as much interest and "aha moments" as that one has. I still remember emailing it to WSR and having the editor come back with shock at the data and revelations in the article. He wondered why no one else had talked about this before. Post publication I have received countless emails, messages and comments saying they had no idea there were such differences. So the data that I have points to exact opposite of what you are saying Arny.

Even the people who know there are source differences think such differences are filtered out before they get to the DAC. This again from the first thread between you and I:


As I showed in the article, what you describe does little to reduce the variations. Reclocking and buffering exists in AVRs yet HDMI often severely underperforms S/PDIF interface. So there should be no solace here and believing otherwise makes people think there is no measured difference.

It these assumptions that lead people into automatically assuming any listening tests showing differences in transports has to be an issue of testers head, than reality of product design . I think people would be a lot more cautious if they knew a) that differences existed and b) they were of amplitudes that measurements show them to be. Please see more below.


I wish we had converged here Arny so that I don't have to keep explaining the same thing over and over again. But we are not there yet. Earlier someone said, "So I feel that it's sort of like THD - sure we can measure it, and we can show that A has .00000001% and B has .0000000000000000000000000001%, but does this make B better in a way that us humans can appreciate?"

Here is a measurement of what 7 nanoseconds of jitter translates as seen in some AVRs:



So we have two distortion products at -80db. What is -80 db? If we convert that to a percentage we get 0.01%. And this is for just *one* distortion sideband, not the sum total as Total Harmonic Distortion (THD) computes. So we are not remotely talking about the tiny numbers mentioned above.

Indeed, a perfect 16 bit system will have a THD figure of 0.0016% -- still way less than above numbers. You can find amplifiers that do better than .01%THD. Who thought before this moment that their "perfect" digital source/interconnect causes more distortion than a power amplifier?

So yes, if we can get everyone to agree we will not have to discuss it. Something tells me there will be objections to this summary just the same, showing we are not there yet .

Why are you keep posting that on audio forum? This is audio forum, you know, the sound you hear.

What is the name of the forum?

What did you write you were going to do with the audibility question?

I didn't need to since your question was based on a faulty premise. You said this was an "audio" forum. The name of the forum is Audio Video Science. The subforum is Audio theory, Setup and Chat. We are having a chat about the science of audio theory.

While I appreciate your plea to not discuss the science, we are within the charter of the forum and subforum to do that. To that end, this is how my article ends:

"My wish in writing this article is not to convince you of audibility of jitter anyway but rather, the precision of communication in discussing performance of products. Think of this video analogy. If I have a 1080p display but I sit too far from it, I may not discern whether it is better than 720p. Because of that, would you call that display 720p? Of course not. The same is true here. We have to stop making arguments against cable effects and such because “digital is digital.” The cable may not make an audible difference but that is no excuse for describing the system operation incorrectly in that way. Architecturally, we have a rather complex system here and understanding how it works is an important part of being an informed consumer."

As I said, some of us want to discuss the science while others don't believe the audible observations and want to do everything to avoid that....

No, the subforum is Audio Related and the subforum of that is Audio theory, Setup and Chat.

Theory about Audio Related matters, which your writing is irrelevant since you don't want to deal with audibility aspect.

See above.


Discuss the science relating to what, inaudible effects? Why are you hanging around on this subforum?

Nope. That is a category. Go ahead and post in it and you will see that you can't .


I am happy to get into it but I fear that you won't be able to follow without understanding of the science. As a test, please explain what this graph means from an AES paper related to this field:




Yeh, looking for love in all the wrong places.

That's a highly imaginative reading of the OP and its context. ;-)

This is an all too frequent kind of post we see from you Amir - a post where you stuff a few paragraphs if not a dozen or more paragraphs of words into your victim's mouth. You've done it to me zillions of times and many other people as well. It's a gigantic waste of everybody's time. You seem to need a hobby or a charity or something more useful in your life than making up posts and falsely attributing them to other people. ;-)

Show me where the OP hooked his music players up to some proper test equipment and found no differences, and I'd see a reason to continue.

Actually, I'd know that he was doing something wrong, because few if any two measurements made with modern test equipment are exactly identical. ;-)

Seeing no such details at all, its very clear that his evaluation was based on a plain old non-level-matched, non-time-synched, sighted evaluation.

Clearly, no test equipment was involved with the OP at all. Therefore saying there were no measurable difference is just a flight of fancy, a repetitious troll, a misrepresentation of obvious relevant facts, a waste of time.

Your dance move #4, "make things up as you go". AKA lie.

deflect, redirect, your dance moves #1 & 2.

How do you find out if it is audible or not? Could it possibly involve using your ears?

Why is that necessary? Your statement was regarding people's belief in this matter and that is how I answered it. You said and I quote, "I am familiar with nobody who currently says that there are no measurable differences between digitial transports." You are in a thread where OP said he thought his two setups were identical. As long as he thought that and "said" it as such, your statement that everyone knows otherwise is incorrect.

But yes, if people tested their players they would not make that assumption. Problem is, they don't think measurements need to be made in the case of digital sources because they consider them to be identical. Bits are Bits. And digital means perfection. Reclocking and buffering fixes all. All myths but powerful ones that stop us from investigating more. We start with the wrong assumption and perform the wrong analysis of the situation. Digital is digital and therefore OP "clearly" imagined a difference.


For analog devices, sure. But that doesn't extend to people thinking replacing digital bit streams causes that. Again I love for that to be true. And maybe people seeing you believe in this so strongly now saves us the next argument.


I appreciate that being your point of view. I am disappointed though that you continue to mention level match as a potential cause but have not managed to make a credible case as to why.


I thought this latest back and forth was a waste of time too until you declared that everyone must know that changing digital transports/interconnects causes analog output of a DAC to measurably change. As I have shown, such differences can be as much as 20 to 40 dB and create distortion levels well above even our power amplifiers. If this is all in agreement, then we have come a long way .

Because as I demonstrated quite clearly, your post as usual made up a question and answered it, just like you are doing here.

I asked you a simple question:


And as usual Amir, you've totally failed to give a relevant answer.

Now Amir I'll give you a second chance.

Where did the OP say anything about measurements?

If the OP didn't say anything about measurements, why did your response go off on a tangent about measurable differences?

If you can't answer those 2 simple questions in a relevant way, don't bother to answer at all!

You asked me to discuss audibility of jitter. I said I am happy to do that but you need to understand the explanation if I am going to take the time to do that. So I post a graph from an Audio Engineer Society paper that shows audibility of digital distortions relative to what we hear and your answer is that it is a lie? If so, then you won't be able to follow the answer you asked me to give. You can't ask someone to speak French to you as to prove that they know the language, only to flunk the test of whether you know its alphabet .

There really is no fortune cookie answers here. Jitter is a complex, data-dependent, and system dependent distortion. You can rule out 1000 variations of it and you still have infinite number left. The approach used in research is to compute at which level we can demonstrate it to be inaudible relative to our threshold of hearing (which *is* measured using listening tests). By applying psychoacoustics to the distortion/noise of digital systems, the two can then be compared as was shown in that paper and others like it. If the distortion can rise above the minimum threshold, then it can be audible.

If you have no patience for explanation of science, perceptual models of our hearing, mathematics that yield the distortion levels, and analysis of the systems at hand, then I am not the man to want to discuss the topic with. I go by science and you seem to not want to do that.

OTOH Amir, if you love science, your posts may not be good ones to respond to because of what they do to good science. ;-)


I would say that the above sentence might be best interpreted as one would interpret the statement: "I go by the cemetery and while I'm going by I look at the flowers. ;-)

I believe you have the same views regarding these papers/researchers, yes?

http://www.aes.org/e-lib/browse.cfm?elib=6773

Authors: Dunn, Chris; Hawksford, Malcolm J.
Affiliation: Audio Research Group, Department of Electronic Systems Engineering, University of Essex, Wivenhoe Park, Colchester, UK

"Is the AES/EBU/SPDIF Digital Audio Interface Flawed?
It is a requirement of high quality digital audio systems that all digital interfaces in the signal path exhibit signal transparency. The widely adopted AES/EBU/SPDIF interface has received criticism from some quarters for a lack of signal transparency; this paper addresses possible problems with such interfaces and presents methods for improving the interface standard."

http://www.aes.org/e-lib/browse.cfm?elib=6111

Author: Dunn, Julian
Affiliation: Prism Sound, Cambridge, U.K.

"Jitter and Digital Audio Performance Measurements
It is well known that timing jitter in digital audio converters can subtly degrade performance. Unfortunately standard audio measurements are not very useful for assessing sensitivity to jitter. Mathematical formulae are derived to relate the modulation artifacts produced by sampling jitter with the jitter amplitude and frequency. The audibility of these modulation artifacts is considered in relation to the jitter spectral content. After examining the main sources of jitter in digital audio systems, measurement techniques appropriate to assessing the sensitivity to each source are described. Results of these measurements are shown for some digital audio products."

http://www.aes.org/e-lib/browse.cfm?elib=12986

Author: Stuart, J. Robert
Affiliation: Meridian Audio Ltd., Huntingdon, UK

"Coding for High-Resolution Audio Systems
What do we mean by high resolution? The recording and replay chain is reviewed from the viewpoints of digital audio engineering and human psychoacoustics. An attempt is made to define high resolution and to identify the characteristics of a transparent digital audio channel. The theory and practice of selecting high sample rates such as 96 kHz and word lengths of up to 24 bit are examined. The relative importance of sampling rate and word size at various points in the recording, mastering, transmission, and replay chain is discussed. Encoding methods that can achieve high resolution are examined and compared, and the advantages of schemes such as lossless coding, noise shaping, oversampling, and matched preemphasis with noise shaping are described."


Again, does this apply to above work?

Your dance move #4 again, "make things up as you go".
Can you quote me asking such question?


You posted a link to your writing yesterday which still says "I am going to punt that question.". You say two different things about one subject. That makes one of them a lie.


Answer to the question of it being audible is yes or no. Once answered properly, the next step is to find out under what condition the test was performed. In your case, based on previous posts (since this is a repeat of same old BS you've been carrying out), you've heard the difference under improperly performed comparison. The next step from there is to do a proper ABX, but instead you are trying to rationalize your bogus listening test.

Sure:

English problem again, amirm. You said I asked you "to discuss audibility of jitter". I asked you "How do you find out if it is audible or not? Could it possibly involve using your ears?" Not the same question, especially when you quote the whole thing instead of half.

So which is it, will you punt the question or will you answer yes / no on jitter being audible from contemporary audio gears?

Why do you want to discuss jitter if it is not audible?

If you don't mind I like to confirm what you are asking. You want me to answer "jitter being audible" while not discussing "audibility of jitter." [bolding mine] Correct?

And what's with that contemporary qualification? OP's CD player is from 1998. Was something broken then that is not broken now? If so what is it? What is the contemporary time period and why?

What part of "audible or not" don't you understand? Let me ask you again, how do you find out if it is audible or not? Could it possibly involve using your ears?

I'm talking about the link where you wrote, ""yes but is it audible?"".

When someone answers the "how," Yes/No falls out of that. And the explanation I gave included the ear and I threw in the brain for good measure!


Yeh but you asked me if it is audible in a "contemporary" audio gear. Is contemporary an undefinable term?

The usual amirm dance, deflect, redirect... 1, 2.
So you are still punting the question if it's audible or not. What a waste of audio related forum bandwidth.


Throwing in a new dance move now? "play dumb", there you go, your dance move #5.
Since you mentioned HDMI many times in that link, perhaps that should be the timeline.

Rats. I knew throwing the brain in there could push you over the edge . Sorry about that. Here's wishing you find someone more rewarding to discuss "audio related" topics with. Take care my friend.

You punt the question "is it audible?” because it is not audible. Imagine the sales potential for your store if it was audible. It would be on the front page of your ad, "Here is $$$ model # *** with lower jitter and it made audible difference in level matched double blind test!".

Now imagine how much it would hurt the sales potential for your store if you revealed the answer instead of punting that question. "Here is $$$ model #*** with lower jitter". "Dose it make audible difference in level matched double blind test?". "No."