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(Not a) good explanation of jitter in TAS
hifitommy
post Jul 4 2009, 22:15
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robert harley who has consummate ability to elucidate just about any description of a sound compares jitter to image stabilizing binoculars. its in the newest issue-#194 with the meridian speaker on the front, august.

...regards...tom
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hlloyge
post Jul 4 2009, 23:12
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New issue of what? Not everyone lives where you live, and I'd like to read that.
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Woodinville
post Jul 5 2009, 01:56
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QUOTE (hlloyge @ Jul 4 2009, 15:12) *
New issue of what? Not everyone lives where you live, and I'd like to read that.



"TAS" The Absolute Sound...

But image stabilization? That's a stretch.


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rpp3po
post Jul 5 2009, 02:44
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QUOTE (Woodinville @ Jul 5 2009, 02:56) *
But image stabilization? That's a stretch.


One could call it the opposite. Image stabilisation addresses spatial but digital audio jitter is temporal distortion. The audio equivalent of image stabilisation would instead be fixing the spatial image between two stereo channels.

A better "analog world" example for jitter correction would be the stabilization of a spiral spring's circular motion with a pendulum in clocks.
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krabapple
post Jul 5 2009, 05:45
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QUOTE (hifitommy @ Jul 4 2009, 17:15) *
robert harley who has consummate ability to elucidate just about any description of a sound



including imaginary ones.
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Canar
post Jul 5 2009, 06:14
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Audiophile gibberish belongs in general audio, not scientific discussion. Moved.


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hifitommy
post Jul 5 2009, 06:30
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"including imaginary ones" WOW, i've found another genius here at h2audio forum!



sorry hlloyge, i wasnt thinking that everyone might not know that abbreviation. i usually post at audioasylum.com where most of us crazies know about it. tas has been doing a great job of evaluating audio equipment since '73 and coined the term 'high end audio'.

robert harley is a digital recording engineer who used to work for reference recordings i believe or a similarly fine company. he is also an analog lover of the first magnitude. when one review equipment at the level he does, MANY more details and nuances become quite obvious.

as for the stretch, perhaps so to illustrate the point, not make a direct equivalency statement. i for one could only imagine what exactly jitter is and how it might affect the sound. i think RH came pretty close with that verbiage.

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greynol
post Jul 5 2009, 07:55
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It's easy to bandy about sarcasm with the word genius just as it is easy for someone to call a subjective audiophile delusional. So far I've not seen ample evidence to conclude either is right as of now.

However, arguing from an appeal to authority won't buy you much in these parts. It's more likely to elicit challenges to any and all people who claim to distinguish one thing from another to prove it through a double-blind test.

If you can't handle such challenges, this is probably not the forum for you.

This post has been edited by greynol: Jul 5 2009, 23:29


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Axon
post Jul 5 2009, 09:35
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I'd appreciate an in-depth description of what Harley actually wrote before the inevitable throwdown that is about to occur.
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Arnold B. Kruege...
post Jul 5 2009, 11:15
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QUOTE (Axon @ Jul 5 2009, 04:35) *
I'd appreciate an in-depth description of what Harley actually wrote before the inevitable throwdown that is about to occur.



Hear! Hear!
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andy o
post Jul 5 2009, 13:00
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QUOTE (hifitommy @ Jul 4 2009, 14:15) *
robert harley who has consummate...

You had me at "robert harley".
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hlloyge
post Jul 5 2009, 13:14
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QUOTE (hifitommy @ Jul 5 2009, 07:30) *
robert harley is a digital recording engineer who used to work for reference recordings i believe or a similarly fine company. he is also an analog lover of the first magnitude. when one review equipment at the level he does, MANY more details and nuances become quite obvious.


Is he? Well, I haven't heard of him anyways, but I know of jitter, so it would be nice if I could find that article to read it and possibly expand knowledge.
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andy o
post Jul 5 2009, 13:18
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Harley was the one that concluded that the glass CD sounded more "analog-like" and other such things, so he's an expert in analog and an analog lover. He's got some articles at our favorite analog-lovers publication Stereophile.

Oh, and this piece of groundbreaking argument against DBT.

This post has been edited by andy o: Jul 5 2009, 13:21
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Woodinville
post Jul 5 2009, 22:40
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QUOTE (Axon @ Jul 5 2009, 01:35) *
I'd appreciate an in-depth description of what Harley actually wrote before the inevitable throwdown that is about to occur.



Yup yup yup


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saratoga
post Jul 5 2009, 23:16
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QUOTE (hifitommy @ Jul 4 2009, 17:15) *
robert harley who has consummate ability to elucidate


There comes a point when you're just communicating so badly you're going to get mocked for it, regardless of substance. This would be it.
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hifitommy
post Jul 6 2009, 01:20
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this place is inviting as a toilet with a razor blade seat. i intend to invoke my will upon you, i just wont sit down. it seems this must be where audio annex is coming to rest. heheheh. cant fool me.
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Canar
post Jul 6 2009, 01:31
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QUOTE (hifitommy @ Jul 5 2009, 17:20) *
this place is inviting as a toilet with a razor blade seat
Show us some science, and we'll love you forever. Show us more of the same subjectivist nonsense and your welcome will be warm as a Canadian winter. That's just how it works. It's like walking into a Mac forum talking about how great Windows 7 is.


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Axon
post Jul 6 2009, 01:33
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This is not exactly a great situation to try to be an apologist for the HA party line by explaining why our derison is so justified. Especially when some people really are being rude. (I love ya, krab, I really do, but was that really necessary?) But there are about 5 billion reasons why we should be contemptful of anything Harley says without engineering or psychoacoustic justification.

tommy, many of us (and I am specifically talking at least half of the posters on this thread) have a far more technical grasp of the mechanics of jitter than we are anticipating reading about in TAS. A good number of us have read Hawksford's papers on jitter simulation. A few of us know how to actually implement a jitter simulator. And most of us know how the audibility of jitter can be evaluated in a by-the-books psychoacoustic (or if you will, flat earth) fashion and grasp why such a large gap exists between what is considered audible in the engineering literature and what is considered audible in the high-end literature.

So, you make a post here - on a forum on scientific discussion - mentioning what we're all pretty sure is going to be a fluff piece that is going to be technically wrong... and you expect us to take it seriously? Of course we're going to chuckle (and mock).

You liken HA to a Audio Annex? I mean, really? HA is like the adult room compared to the kiddie rooms of, say, Audio Asylum. If you post, back your sh*t up, or be educated. Don't make personal insults and don't get emotional or personal. Don't make claims of audibility unless you can prove only aural senses are involved. These are not hard rules for educated adults to follow.


But hey.. you're an adult! And you want to learn! Pull up a chair! Let's get down to bidness. In terms of relating jitter to image stabilizing binoculars... image destabilization can be treated mathematically as an image convolution with a profoundly asymeetric kernel. Just to make this brutally clear:

x =

(CC-BY-NC-SA 2.0: attribution)

Convolution is a filtering operation, like a lowpass filter, or an eq, or an antialiasing filter. It doesn't really map very well to the domain of temporal distortions, at least not from the little bits of text you are quoting. The notion that it smears or occludes detail in a recording is only true in the most absolute general sense - that all distortions can do things like that - but if I were to try to formulate an accurate analogy between digital audio jitter and digital photography, I would think a better analogy would be taking a photograph with an image sensor whose pixel cells were radically misaligned with respect to one another:



But Harley didn't mention any of that in his article, did he? Of course not. I guess nitpicking on analogies is still nitpicking, but without seeing the article, it does not give me all that much confidence in it.

This post has been edited by Axon: Jul 6 2009, 02:11
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Axon
post Jul 6 2009, 02:12
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QUOTE (Canar @ Jul 5 2009, 19:31) *
QUOTE (hifitommy @ Jul 5 2009, 17:20) *
this place is inviting as a toilet with a razor blade seat
Show us some science, and we'll love you forever. Show us more of the same subjectivist nonsense and your welcome will be warm as a Canadian winter. That's just how it works. It's like walking into a Mac forum talking about how great Windows 7 is.


Um... comparing HA to a Mac forum is rather insulting. Of us.
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Canar
post Jul 6 2009, 03:00
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Yeah, bad analogy, I know... I was trying to capture the flavour, but apparently unsuccessfully. Quitting caffeine is rough.

This post has been edited by Canar: Jul 6 2009, 03:01


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rpp3po
post Jul 6 2009, 03:24
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The most comprehensive, insightful, and freely available text about jitter and clock recovery is this (page 11) by Robert W. Adams. Pretty much said it all in 1994.

Edit:

laugh.gif laugh.gif

Haha, what a funny coincidence! I just found that the above article even has a one page prolog explicitly showcasing this Robert Harley and how he was making a fool of himself by totally misunderstanding jitter and misleading others about it.

This post has been edited by rpp3po: Jul 6 2009, 03:39
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hifitommy
post Jul 6 2009, 03:53
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tas isnt scientific american nor does it claim to be anywhere near that pub. maybe RH didnt hit the nail on the head but tried an analogy for the non technical crowd. and perhaps this particular board at HA was a poor choice for an initial hobbyist post.

i can at least be respectful of the fact that none of you stooped to using emoticons. thank you axon for lightening the load on my neurons.

...regards...tom
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Ed Seedhouse
post Jul 6 2009, 03:55
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A "good explanation of jitter in tas" eh? I've yet to see much other than obfustication in TAS. Well, I suppose seeing is believing, but if you don't mind I won't be holding my breath in the meantime.


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krabapple
post Jul 6 2009, 04:01
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QUOTE (greynol @ Jul 5 2009, 02:55) *
It's easy to bandy about sarcasm with the word genius just as it is easy for someone to call a subjective audiophile delusional. So far I've not seen ample evidence to conclude either is right as of now.


You didn't read his Stereophile manifesto anti blind testing?

If you want some more giggles, pick up a used copy of his 'Complete Guide to High End Audio'; I perso nally was deeply, er, impressed by his views on the effect of copper crystal directionality on cable sound (and no, I'm not going to dig the book out an quote it again). But since I've been called rude for noting Harley's woo tendencies, here's a reviewer who gave it a '3' out of 5....trying to put the best face on it.

http://www.amazon.com/Complete-Guide-High-...By=addThreeStar

QUOTE
This book is:
Almost what the High-End Audio industry needs

It's important for me that a book be written on the advantages of high-end audio. It's the business I'm in and it is dear to me on a personal level. There are many excellent portions and handy information pieces scattered about the book and that's the good news.

I will refrain from personalizing my complaints and stick to the issues as I see them. To write this book as the author, you should know Ohm's Law. Harley does not. This is made evident in several examples. Amperes, voltage and wattage are all part of a greater equation that appears to mystify the author. The basic laws of physics and simple electrical concepts need be firmly grasped prior to making an endeavor such as this. There are many elements of "Dark Science" in the high-end audio realm and a mystique that is largely relevant. This book does a strong job of handling that delicate balance between science and myth, that is so important to this industry. Along the way however it forgets to "check the science"

That's too bad, but not a total loss...

A serious explanation of negative feedback as used in power amplifiers would have been pretty easy to put down for the record. Most power amp manufactures have fascinating solutions to the problems associated with negative feedback. A breakdown of a few of the key developments in this area would have been excellent. An opportunity missed. Instead he uses an example of a negative feedback amplifier and calls it just the opposite! At that point in the book I admit I was a bit frustrated.

The good parts are many!
It's an enjoyable read when the author sticks to what he actually knows, acoustics and auditioning gear. I learned much and felt the key points were illustrated clearly and in the contexts of meaningful application. I am not saying "don't buy"

I guess I'm saying this book missed a huge opportunity simply by not getting some important parts right. That's all.


Btw, Axon...that bottom pic, c'est tres Seurat!



This post has been edited by krabapple: Jul 6 2009, 04:17
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greynol
post Jul 6 2009, 05:12
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QUOTE (krabapple @ Jul 5 2009, 20:01) *
You didn't read his Stereophile manifesto anti blind testing?

That should be a rhetorical question, otherwise one might consider me a liar. I should have known better based on the looks of the responses and the little that I did read since I gave mine.

It would seem that we need not have another anti-audiophool fest in this discussion since it appears that hifitommy has realized that he's amongst a group of people who understand digital audio to a depth that is beyond what is written in magazines designed to part people from their money.


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