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Jitter and other topics from Malcolm Hawskford

66.220.116.118
Posted on November 4, 2009 at 11:39:16
audioengr
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 Malcolm Hawksford was interviewed in the November issue of AudioXpress. He talks about skin effect in cabling, I/V conversion, D/A and jitter. Jitter discussion is on page 15. You can purchase the issue online at:

http://www.audioxpress.com

Here are some jitter tracks that he generated that can be downloaded:

Audio tracks from the article The Essex Echo: Audio According to Hawksford, Pt. 1

http://www.audioxpress.com/magsdirx/ax/addenda/media/hawksford_jittertracks.zip

Steve N.
Is A DAC Only As Good As How Well It Handles Jitter, posted on November 5, 2009 at 17:12:45
Dynaudio_Rules
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 If so then why is the Weiss DAC so highly acclaimed while the TC Konnekt isn't even though the Weiss uses TC's anti jitter technology?



Scrutiny Strengthens The Truth and Breaks Down Lies 音楽は天国と地球のかけ橋
JetPLL, posted on November 6, 2009 at 17:18:22
Tony Lauck
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  Since: February 24, 2009
 For those who might be curious, I tracked down some technical information on the TC jitter reduction technology.

Tony Lauck

"Diversity is the law of nature; no two entities in this universe are uniform." - P.R. Sarkar

RE: Is A DAC Only As Good As It's Own Clock - Used Asynchronously, posted on November 5, 2009 at 20:22:19
cfmsp
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That's easy to explain.

My understanding is that Weiss uses TC's JET PLL technology only for their AES/EBU interfaces - which are inferior to their Firewire interface - and they use their own Firewire drivers for the Firewire interface.

Weiss' reputation is based on the quality of sound via Firewire.

If TC Konnekt uses this technology for their Firewire interface - which seems to be the case after a cursory look at their website - they are not using Firewire to it's best advantage, i.e. asynchronously.

IOW, they might as well be using standard USB.

clay
RE: Is A DAC Only As Good As How Well It Handles Jitter, posted on November 5, 2009 at 18:03:58
Phelonious Ponk
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 Put it in an aluminum case and move the decimal point to the right and it would probably be a huge audiophile hit.

P

Exactly, posted on November 5, 2009 at 18:14:08
Dynaudio_Rules
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 Its funny how obvious the bias is....

I want to see how people can justify why the Weiss is or should be better than the Konnekt.



Scrutiny Strengthens The Truth and Breaks Down Lies 音楽は天国と地球のかけ橋
RE: Exactly, posted on November 6, 2009 at 12:45:58
audioengr
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 Even if they were identical technology, the implementation is different. Implementation makes all the difference. I've listened to the Konnekt, but only for a few minutes and from the digital out.....

RE: Exactly, posted on November 6, 2009 at 17:12:12
Dynaudio_Rules
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 "I've listened to the Konnekt, but only for a few minutes and from the digital out..... "

Thats too bad...from what I understand it is discontinued...

Whats really a shamed is that cost effective products are immediately put aside as crap. I've heard more expensive DAC's that sounded much much worse, not being nearly as musical.

I am sure you are aware that many people were using it for the Firewire to spdid out rather than as a pure DAC....namely with the Altman attraction DAC with stellar results.



Scrutiny Strengthens The Truth and Breaks Down Lies 音楽は天国と地球のかけ橋
RE: Exactly, posted on November 7, 2009 at 10:56:48
audioengr
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 I did listen to it in this mode and I was dissappointed. One of my colleages brought it over to compare in my system.

No fair, posted on November 7, 2009 at 14:58:50
Dynaudio_Rules
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 Your system in tweaked with top notch gear...can you be objective?

You need to de-sensitize yourself for a few hours first....listen to a Bose system with a receiver.



Scrutiny Strengthens The Truth and Breaks Down Lies 音楽は天国と地球のかけ橋
RE: Exactly, posted on November 7, 2009 at 10:18:31
Phelonious Ponk
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 "Whats really a shamed is that cost effective products are immediately put aside as crap. I've heard more expensive DAC's that sounded much much worse, not being nearly as musical."

It is a shame. Fortunately it only happens among the misguided few. Throughout most of pro audio, a much higher price/performance ratio is an absolute necessity. The the higher reaches of the mainstream or "midfi" are getting excellent results for the dollar, too. Cambridge Audio is, IMHO, a giant killer. Their integrated amps, particularly. Haven't heard the DAC Magic.

P

RE: Exactly, posted on November 7, 2009 at 15:02:58
Dynaudio_Rules
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 I agree, many so called mid-fi gear are indeed giant killers...and Cambridge is a good example. I went to a dealer and preferred IT over a Krell integrated.

Even now I have an old Hafler amp that is about the most musical amp I have ever heard under 3K....too bad it just doesnt have enough balls to drive my Dynaudios.



Scrutiny Strengthens The Truth and Breaks Down Lies 音楽は天国と地球のかけ橋
RE: Exactly, posted on November 7, 2009 at 20:41:40
Phelonious Ponk
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 I love the old Haflers. And early 70s Harman Kardons. And the but of 2 channel stuff Yamaha is making today is better than most of the so-called "high end" SS out there. Of course there are exceptions to that rule, "high-end" that truly is.

P

RE: Exactly, posted on November 5, 2009 at 20:25:20
cfmsp
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It's rather easy to justify, please see my post above.

Also perhaps you need a reminder that each and every DAC also has an ANALOG section. :)

BTW, I don't own a Weiss, nor do I plan to.

clay
RE: Exactly, posted on November 6, 2009 at 02:19:32
Phelonious Ponk
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 Well, that only means that they are not exactly the same DAC. But justification of any price differential is easy enough. It only requires people willing to pay the price.

P

RE: Exactly, posted on November 6, 2009 at 05:00:40
cfmsp
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Ahh, where's Ashley when we need him - to tell us that the DAC chips should only be implemented according to the designers instructions, as if that was all that mattered in a DAC implementation. :)


clay

RE: Exactly, posted on November 7, 2009 at 10:58:12
audioengr
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 This is why I've given up hope on the "other forum"?

RE: Exactly, posted on November 7, 2009 at 16:29:50
cfmsp
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Ashley 'left' there a looong time ago.

Unfortunately, so did Tim.

clay
RE: Exactly, posted on November 6, 2009 at 05:48:28
Phelonious Ponk
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 He's staying out of the fight these days. But as difficult as his POV was for some people to hear, he was a lot more right than wrong.

P

RE: Exactly, posted on November 6, 2009 at 06:03:46
cfmsp
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I won't disagree with you there.

I do think his (seemingly) absolutist, doctrinaire style was unfortunate, and didn't exactly help his cause (beyond a certain group who immediately jumped on his bandwagon for that precise reason - he was standing up against the established audiophile crapola).
RE: Exactly, posted on November 6, 2009 at 06:31:10
Phelonious Ponk
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 Unfortunate...perhaps. My style is much gentler, evidenced by the warm reception I've received here from the local tweakers :). I understand the emotions of his position. The push, I think comes from the difficulty of having, after a lifetime in pro and high-end audio, produced such a remarkable product at such a remarkable price and then having to watch people talk such complete nonsense and not only be paid a king's ransom for it, but do great damage to the industry with it. That can't be easy. But at the core, what Ashley believes in is not new, it has merely been lost...

“Audio as a hobby is dying, largely by its own hand. As far as the real world is concerned, high-end audio lost its credibility during the 1980s, when it flatly refused to submit to the kind of basic honesty controls (double-blind testing, for example) that had legitimized every other serious scientific endeavor since Pascal. [This refusal] is a source of endless derisive amusement among rational people and of perpetual embarrassment for me..”

-- Gordon Holt, founder of Stereophile Magazine, from the peace and perspective of his retirement.

Mr. Holt is no gentler than Mr. James, for many of the same reasons. And he's right.

P
It was only matter of time before you brought up the Holt's tired quote -, posted on November 6, 2009 at 07:55:07
carcass93
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 as did almost every other think-alike before you.

To that "loss of credibility", whatever that means to you and him, I say - good riddance. Like you say, "it has merely been lost" - to which I'd like to add, "hopefully for good".

Regarding the remarkable product at remarkable price - I'm sincerely happy for you, that you found your ideal. Besides, your gear preferences obviously do not increase demand for the products I could be potentially interested in - that's a plus, too.

RE: It was only matter of time before you brought up the Holt's tired quote -, posted on November 6, 2009 at 08:33:20
Phelonious Ponk
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 I take small comfort in knowing it took me a lot longer to come up with the Holt quote than it took you to accuse me of holding measurements above sound, merely because I believe in the measurements and hear things differently than you do. Which took about one post.

This is the thing that bugs me about subjectivists. If they could simply say that they don't care what the measurements say, they prefer the sound of X, that would be fine. But so many of them are not subjective at all. They have to discredit what the measurements say and declare what they hear superior. And so the old argument continues.

P

RE: It was only matter of time before you brought up the Holt's tired quote -, posted on November 7, 2009 at 12:03:33
aljordan
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 I think those who are strongly objectivists and those who are purely subjectivists force their experiences to be slave to their world view, because their minds are too closed to entertain the possibility that something exists outside of their narrow beliefs.

Regards,
Doctor Alan,
PhD in run-on sentances.

RE: "And he's (Holt) right.", posted on November 6, 2009 at 07:41:56
rick_m
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 No he's wrong. Dead wrong.

We are simply a bunch of self-effacing weenies to even consider that our hobby isn't universal due to something we're doing wrong. For one thing, who gives a politician what other people think? None the less, here is what I think...

History holds the answers, we just need to fill in the right questions. Home audio didn't used to be a niche, it was a breakthrough. Radio and recordings brought entertainment, civilization, fun and pleasure into homes all over the world. Early radios were expensive propositions, more comparable to audiophile prices than boomboxes. I remember my Dad saying how much he spent on one for his folks and it was well over a month's salary.

But time marched onward and TV dethroned radio for entertainment and status thus fewer people listened to 'just music' at home. However in those days only adults had TV's and us marginalized kids only had audio. Some of us never outgrew it and that's why there is such a clump of now old audiophiles. We are a quirk. It doesn't take much foresight to predict that sex, music and drugs will morph together into direct pleasure center stimulators one of these days and that some of us will still cling to music. Hey, too much stimulation is dangerous to folks our age!

Point is you can't judge the steady state future of a pastime by the height of it's peak. Nothing went wrong with paintings, books, music, theater, radio, bowling, bridge, visiting, barbecues, etc. In many cases there may be more people enjoying them than ever before simply because there are so many more people alive just now. But the percentages for each activity may be down.

I don't know the numbers, but I sure see a lot of people with transducers jammed into their ears. I bet more people than ever are enjoying recorded music nowadays. And the technology is serving the message, do you doubt for a moment that their gear is adequate for the material? But the sorts of music that I grew up with and love, classical, folk... require a somewhat better bandwidth and dynamic range to work well.

Then there are the, the what? Connoisseurs? People that really dig subtle qualities in particular things for some reason or another. Audiophiles are people that are especially moved by not just music, but the sound. Not that the music doesn't matter, but the sound itself is unusually important to them (us) [me].

Do you find art lovers making fun of themselves because they can't tell the difference between a real and fake painting yet believe that the first is precious and the second valueless? How about gastronomes who prefer Betty Crocker in a blind test?

So to critics of audiophiles I say 'to hell with you'. What I love, do and care for is none of your business. If you don't like to swim, stay out of the water. Why don't you go plague cooking sites or point out to Harley lovers that Hondas are better in every quantifiable aspect?

We have no need to be defensive about our interest or harbor some inane belief that if everybody doesn't feel the same way that we are failing somehow. By definition 'audiophiles' wouldn't exist if everybody felt the same way, we would just be 'normal'!

Holt wasn't right, just bitter. Tough. The fun's still there for the rest of us. Say, could you give me some tips on how you got so gentle...

Rick

RE: "And he's (Holt) right.", posted on November 6, 2009 at 08:49:25
Phelonious Ponk
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 My, my, such anger. Sorry, I should have added a MHO, YMMV. And I should have been more clear. The thing Holt was right about was that most of the audiophile press, public and providers have:

"flatly refused to submit to the kind of basic honesty controls (double-blind testing, for example) that had legitimized every other serious scientific endeavor since Pascal."

There are exceptions among high-end products and companies, but they are certainly not the rule. And I know from recent, local, personal experience that if you suggest that such measurement might be an indication of reality, you get shouted down very quickly. Yeah, I think Holt was pretty right on that count. Does it bear sole responsibility for the state of the audiophile endeavor? Probably not. Do you care what other people think? If you did not, your answer to people with Holt's and my POV would be ACTUALLY subjective. It would be something on the order of "I really don't care if this gear is objectively inferior to stuff that costs a fraction of what it does, I like the way it sounds and I'm willing to pay the price."

But it seldom stops there. The science must be dismissed or discredited. The subjective choice must be declared superior.

P

RE: "The subjective choice must be declared superior.", posted on November 6, 2009 at 11:45:19
rick_m
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 Darned tootin! And we turn to science as a method to enhance that experience. I don't see a conflict between 'science' and subjective experience.

I'm curious what measurement(s) would cause you to believe one item is objectively inferior to another. (I've got a little list...) Clearly to many posters on AA the parameter that holds sway is cost, the more the better. But if one takes a slightly more nuanced and intelligent look at the system things get a lot blurrier. Depending upon the implementation certain aspects may be sacrificed a little to gain subjectively more important performance in other areas or to dramatically reduce system interactions thus providing more performance to more people more of the time.

Stereophile hasn't abandoned science. They measure, they listen, they report. JA@S is vastly superior to what JH@SR was. But I think that they could do even better. They really took the lead on the jitter issue and I believe to a large extent we have them to thank for having as good as sound as we do today. Unfortunately they have steadfastly refused to address other longstanding issues like PSR ratio and EMC. A long time ago (~15 year) I brought up measuring power supply rejection during a panel at one of their shows, the (now late) gentleman that answered my question, can't remember his name, hemmed and hawed and finally said that was because there were no appropriate standards. Boy, talk about a weak response. You may not believe it after my recent post, but I actually managed to restrain myself from telling him exactly how and why on the spot and just said 'thank you'.

There is one area where I'm fed up to the gills with all marketing and no substance and that's cables and power 'conditioners'. It's like everyone has taken a drought from the "facts-bad kool-aid pitcher". I can't imagine anyone in their right mind buying a garden hose stuffed with wire and crystalized snail-slime for thousands of dollars without any understanding of what they are buying. If the kilobuck cable really 'makes the black blacker' it is surely a dawdle to provide a little graph showing the transfer impedance or loss vs frequency. I mean some of these suckers are tens of thousands of dollars and it would take a technician say two hours to prepare the graph.

Or, a widely read journal could actually measure them!

OMG, I'm starting to sound like you...

Rick

RE: "The subjective choice must be declared superior.", posted on November 7, 2009 at 03:11:28
Phelonious Ponk
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 "OMG, I'm starting to sound like you..."

-- Welcome to the real world, Neo.

ON EDIT: Sorry, I was so excited about the possibility of having met another rational audiophile I forgot to answer your questions. What measurements might indicate objective superiority? Might being the key word, I think we could just start with some basic understanding -- that the purpose of high fidelity is reproduction, that it refers to high levels of fidelity to the original recording, and if that recording is good enough, the original performance event. If we get that, then the levels of noise and distortion and the accuracy of the frequency response should be a good start. Pretty basic stuff. Of course there are all kinds of noise and distortions, even some fairly new ones in the digital world, and there is often the very fundamental debate of what is audible. In that case, as Holt suggested years ago, blind listening tests are the answer. In spite of all of the objections of many audiophiles, and all of the objectionable hobbyist testing that has been done and indicated little, it's not that difficult to conduct them in a controlled and objective manner that delivers statistically significant results. In other words, It's not hard to determine whether or not a claimed difference is actually audible. Personally, my alarm kicks off when any vendor is claiming results that are not measured, or, far worse, claiming immeasurable but audible results that have not been verified in blind testing. I can't even remember a case of the latter.

Incredibly, quite a few audiophiles seem to take exactly the opposite approach: They embrace those who claim great results without evidence while distrusting all evidence but the subjective evaluation, which miraculously leads to a determination of the objective superiority of their choices. The logic escapes me.

P

RE: "The subjective choice must be declared superior.", posted on November 7, 2009 at 06:33:29
rick_m
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 I'd like you to consider this question: Is the audibility of errors what matters or is it their objectionably? I suspect this dichotomy is the thing that causes the rift over DBTing.

"that the purpose of high fidelity is reproduction, that it refers to high levels of fidelity to the original recording"

OK, but it's the larger scope that's the real test, the reproduction's ability to impart the same feelings as the original. Errors which cause distractions can keep those feelings from building up.

Where I'm headed is that I think that there are many errors that are fairly easy to hear in an A/B test but typically don't matter very much. Broad frequency response variations for instance. Yet other things with a very small net energy impact can prevent you from getting into the music. It has to do in my mind with the 'naturalness' of the error. Things that bug me are things that mess up the temporal aspect of the reproduction like resonance in speakers, and unnatural distortions like crossover. But they can escape notice at first since the biggest indicator of their existence is the lack of listening pleasure.

I'm rational. That's the same as fractional, i.e. marginal isn't it? But this hobby is about sensuality. If it doesn't feel good, something's wrong and hopefully we can use our analytical side to try and fix that up. The only reason we listen to music is to influence our emotions...

WRT vendor claims, we are sort of in the same boat. I guess it depends on just what they claim and how they say it. I read an ad or 'whitepaper' or something by a powercord mfg a while back and it annoyed me no end. They were saying that their cord had something special that filtered out line noise. Great I thinks, how well and look around for the Specs. only to discover that there are none. Measurements, none. Credibility, none.

Rick

RE: "The subjective choice must be declared superior.", posted on November 7, 2009 at 08:47:35
Phelonious Ponk
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 I think we're probably actually pretty close in our beliefs, and yes, the objectionability of errors is of primary importance. Audio reproduction has always been fraught with compromises; it probably always will be. Picking the right compromises, the ones that don't distract from enjoyment of the music is pretty important. I personally go for "neutrality" until I get to transducers, where it is, as of yet, impossible, and choose my compromises there. It saves me the long, expensive, frustrating search for synergy.

But while this really shouldn't be an issue, it is: Before we start discerning between objectionable and unobjectionable errors, it might be useful to determine if they're audible. This should be a primary objective of the audiophile press. Unfortunately, it is often the opposite and they are often the greatest proponents of the haziest phantoms.

Anyway, that's how I hear it. I understand that it's not the most popular point of view around here, and I appreciate the board being open enough to allow for an alternative. That's not the case everywhere.

P

RE: "The subjective choice must be declared superior.", posted on November 7, 2009 at 10:23:16
rick_m
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 "Before we start discerning between objectionable and unobjectionable errors, it might be useful to determine if they're audible."

OK. I too like being able to discuss partially off-topic topics. But this isn't much off topic because I think we are still sorting out the relevant distortions from our newish digital sources and even solid state gear. The mere fact that they keep getting better puts a lie to the notion that they were perfect from the get-go yet if measured by the "objective" criteria from the record/tube era, they essentially were. This is pretty strong evidence that our measurements and interpretations have never included enough factors to reliably predict the listening experience.

Going for neutrality can only be done on a system basis from my experience, hence the quest for synergy. Ultimately that should all be behind us and anything that is heard, but "not measurable" is ripe for investigation. Understanding the nature of these things, and I like Tony's name for them: evil, is the key to determining audibility and controlling them.

Much work has been done and the many faces of jitter have been implicated over and over in a host of aural problems. Yet how many of us can state with confidence that we currently have it reduced to the point of no concern? Not me, that's fer sure.

Rick

RE: "The subjective choice must be declared superior.", posted on November 7, 2009 at 10:37:52
Phelonious Ponk
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 I think I can say I've reduced jitter to the point of no concern, because I'm not concerned. Is it possible that jitter is audible in my system? Sure. But I can't identify it. I'm not hearing any "evil" distortions. And any anomalies that might be there, other than the obvious recording problems and transducer limitations, are things I'd have to listen for, and probably train myself to hear. Why would I want to do that? This much I know is certain: I've tried many amps and several DACs, and the veil lifted for me when I went to single drivers, then active systems.

I suspect, while thoroughly understanding there is strong disagreement, that listening for jitter through conventional passive systems, is like looking for a pin through a blind fold.

P

RE: "The subjective choice must be declared superior.", posted on November 7, 2009 at 12:15:06
rick_m
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 Well, considering your system choice it would be tough to know where you stand jitter-wise. But as you essentially say, if you love the sound, who cares. That's largely my philosophy also as it's the bottom line.

I did just look up the Specs. on your speakers and they say:
"Up to the minute 24/192, completely jitter free design." Guess that answers the question, perfection should be adequate for anyone. I do wonder how they keep it up to the minute, must be sort of a DAC of the month club...

I doubt that mine is "completely jitter free" and being about eighteen years old it's more seasoned than "up to the minute". I see something faster in my future.

As I've said before, having this stuff in the speakers really appeals to me, too bad they don't seem to have any acoustic suspension models, ported speakers just haven't been keepers for me.

Rick

RE: "The subjective choice must be declared superior.", posted on November 7, 2009 at 20:03:46
Phelonious Ponk
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 Just between you and me, I think "completely jitter free" is a bit hyperbolic. :) With jitter below audible levels is, in my view, quite achievable, often achieved. I think jitter is highly overrated. Mostly be people selling very expensive jitter reduction.

P

"science must be dismissed or discredited" - that's your main problem., posted on November 6, 2009 at 10:03:03
carcass93
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 What you think is science is not - and that's the root of all confusion, and proclamations that sound ridiculous to anyone who has first-hand EXPERIENCE with the matters.

RE: "science must be dismissed or discredited" - that's your main problem., posted on November 6, 2009 at 10:08:21
Phelonious Ponk
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 Enlighten me, Carcass. What do I think is science? You've yet to be able to accurately paraphrase what I've said, it should be rich to see your interpretation of what I think.

P

We could start by revisiting the question why..., posted on November 6, 2009 at 10:29:21
carcass93
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 ... a DAC, designed and measured according to what you think IS science, sounds inferior to ones that exhibit inferior measurements, according to the same brand of science.

If you wish, you could also refer to ongoing discussion on PHP on the same subject - some posts there contribute to clarification of that matter.

Of course, for that to make any sense, first you would have to accept the hypothesis that they do sound BETTER, not just different - one of the participants there was unable to wrap his mind around it.

RE: We could start by revisiting the question why..., posted on November 6, 2009 at 11:16:05
Phelonious Ponk
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 ".. a DAC, designed and measured according to what you think IS science, sounds inferior to ones that exhibit inferior measurements, according to the same brand of science."

-- Are you still on that? Goodness, you must own one of those DACs with a little valve sticking out of it's head. No wonder I'm such an offense to you.

"Of course, for that to make any sense, first you would have to accept the hypothesis that they do sound BETTER..."

-- Well, I suppose that IS the gist of it. That's not a hypothesis, it is an opinion (back to that science thing...) And even though the numbers, and the very purpose of a digital to analog converter (as opposed to colorist) are on my side of the difference, I'm willing to accept that you may like the colored one better, and that we could be finished here. You, evidently, are not. It appears that it's not enough that it sounds better to you. It must be objectively superior to validate your opinion, therefore scientific measurement must be wrong, or at least inadequate. And those who disagree with what you hear either haven't heard or have been unable to wrap their minds around it.

Do I have that about right?

P

RE: We could start by revisiting the question why..., posted on November 6, 2009 at 12:38:43
Tony Lauck
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  Since: February 24, 2009
 You are creating a false dichotomy between objective measurement and subjective perception. All DACs are going to be colored when working at 44.1 kHz, such are the inevitable limitations of the sampling rate. There are trade offs in how coloration manifests.

Relying on a partial set of known measurements to claim one product "accurate" and another "colored" is inappropriate. One could use a different set of known measurements and reach the opposite conclusion, using purely objective considerations. It is not necessary to posit the possibility of new measurement techniques or as yet to be manufactured test equipment, existing data will do just fine to refute your false dichotomy.




Tony Lauck

"Diversity is the law of nature; no two entities in this universe are uniform." - P.R. Sarkar

RE: We could start by revisiting the question why..., posted on November 6, 2009 at 20:49:27
Phelonious Ponk
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Posts: 557
Location: NC
Joined: September 3, 2007
 I don't think I've proposed your false dichotomy. I haven't said, and don't believe that any piece of audio is absolutely transparent, perfectly accurate. I do, however, believe that some components produce flatter frequency response and lower noise and distortion than others. Don't you? I also believe it is absolutely OK to prefer the one with the less accurate specs. But a few days ago, in another thread, Mr. Carcass seemed to be insisting that the less accurate DAC was better because it was more expensive. That's just silly.

P

What IS silly - putting words in somebody's mouth, like you do,..., posted on November 7, 2009 at 14:43:00
carcass93
Audiophile

Posts: 2634
Location: NJ
Joined: September 20, 2006
 ... and then arguing with that.

But then, it's you, after all...

RE: What IS silly - putting words in somebody's mouth, like you do,..., posted on November 7, 2009 at 20:33:18
Phelonious Ponk
Audiophile

Posts: 557
Location: NC
Joined: September 3, 2007
 What words did I put in your mouth? Are you talking about these?

"But a few days ago, in another thread, Mr. Carcass seemed to be insisting that the less accurate DAC was better because it was more expensive. That's just silly."

Because with those words, I was referring to Audio Doctor's thread about his new Cosecant, in which someone said,

"You are not suggesting that a $975+ Dac should compete with a $3500 DAC are you?

...and you replied...

"I'm sure he's not, but there are shitheads that DO suggest that and much more."

...I didn't put those words in your mouth, I got them out of it. I just left the nasty name-calling ones behind. But maybe I mistook your meaning. When you implied that only shitheads would suggest a $975 DAC could compete with a $3500 DAC, did you somehow mean that it possibly COULD compete with the more expensive DAC?

P
Distortion, evil or otherwise..., posted on November 7, 2009 at 07:26:41
Tony Lauck
Audiophile

Posts: 3048
Location: Vermont
Joined: November 12, 2007
Contributor
  Since: February 24, 2009
 OK. Perhaps you are merely guilty of embracing the dichotomy, or maybe merely being an innocent bystander. And if it is all in the name of Rhetoric while debating with Dr. Carcass, so be it... Unfortunately for me, I have a tendency to get hot under the collar when people invoke the "S" word to imply that others aren't "s". IMO, most discussions concerning measurements should be using the "E" word, if not the "M" word, as in "M BS".

Mostly, I use measurements to tell if equipment is still working as it was originally designed, or if there are peculiar faults that might show up only under certain conditions. Otherwise, I use my ears. For tweaking, measurements are indispensable when possible, because a measurement is likely to be much quicker and more reliable than a subjective listening test. Unfortunately, some of the necessary measurements haven't been invented yet, other commonly used ones are simplistic, and others (such as some of the jitter measurements) require very expensive test equipment. So measurement can never be a substitute for listening, quite apart from questions of preference.

I concern myself with non-linear distortion much more than with frequency response variations, especially frequency response variations that are similar to naturally occurring objective effects (high frequency air roll-off) or to naturally occurring subjective effects (variations on the equal loudness curves with changing SPL). I am not terribly concerned about noise that is uncorrelated with the music, e.g. dither noise that remains well below audible levels regardless of the musical signal. However, any change in "noise" that is correlated with the signal fall into my category of "distortion" and if that correlation entails complex modulation artifacts they fit into the my most objectionable category, "evil distortion".

So for me, when looking at a DAC on a sine wave test, in addition to seeing no harmonics sticking their ugly head above the noise floor, I want to see the noise floor remain unchanged as the level of the sine wave goes from -0.1 dBfS to -90 dBfs. This would be for all frequencies in the audio band from 20 Hz to 20,000 Hz. In keeping with my view of "natural distortion" constant background noise corresponds to the random motion of air in the recording venue or listening room. There are no corresponding natural processes that create noise modulation commonly seen with digital audio, so this falls into the category of unnatural distortion, and hence unless in very small doses, "evil distortion". High order harmonic distortion created by excessive negative feedback is, of course, the classic case of "evil distortion".

Tony Lauck

"Diversity is the law of nature; no two entities in this universe are uniform." - P.R. Sarkar

"Dr. Carcass"? I'm flattered... But really, I dreamed of being D.V.M. when I was little. N/T, posted on November 7, 2009 at 20:27:51
carcass93
Audiophile

Posts: 2634
Location: NJ
Joined: September 20, 2006
 N/T

Doctor of Internet Invective? :-) nt, posted on November 8, 2009 at 07:07:20
Tony Lauck
Audiophile

Posts: 3048
Location: Vermont
Joined: November 12, 2007
Contributor
  Since: February 24, 2009

Tony Lauck

"Diversity is the law of nature; no two entities in this universe are uniform." - P.R. Sarkar

Oh, that... No, merely Bachelor of said Science (Art?). Working on my Masters. N/T, posted on November 8, 2009 at 08:34:50
carcass93
Audiophile

Posts: 2634
Location: NJ
Joined: September 20, 2006
 N/T

Nope, you don't., posted on November 6, 2009 at 11:31:44
carcass93
Audiophile

Posts: 2634
Location: NJ
Joined: September 20, 2006
 But explaining why would be obviously in vain.

And no, I don't own neither Wavelength nor Ayre, and I also don't own any tube equipment. And yes, what I have sounds superior to Benchmark.

RE: Nope, you don't., posted on November 6, 2009 at 20:54:33
Phelonious Ponk
Audiophile

Posts: 557
Location: NC
Joined: September 3, 2007
 Sorry, I had to be away for a few hours, but I thank you for continuing to make my case in my absence.

P

Problem is it's wrong!!!!!, posted on November 5, 2009 at 06:20:40
Gordon Rankin
Manufacturer

Posts: 2247
Joined: June 9, 2000
 Gang,

How is it that people of this technical nature cannot even flush out what is technically correct or not.

Adaptive is Adaptive and the confusion over the difference from Asynchronous Upsampling and Asynchronous USB should be made clear in this article and yet it is not. They mix it up and don't even mention the USB interface is Adaptive but yet say it is Asynchronous.

Really!!!!

The editor has been informed of the errors and we hope he will print the corrections in the next issue.

Thanks
Gordon
J. Gordon Rankin
RE: Problem is it's wrong!!!!!, posted on November 5, 2009 at 09:34:38
Thomas James
Audiophile

Posts: 91
Location: Vancouver
Joined: May 27, 2004
 Gordon, can you turn the volume down on the exclamation points?

Just another opportunity, posted on November 6, 2009 at 12:48:45
audioengr
Manufacturer

Posts: 4088
Location: Oregon
Joined: April 12, 2001
 To tout the benefits of Async USB. Nothing like free advertising.

What will Gordon do when we all have it I wonder?

RE: Just another opportunity, posted on November 7, 2009 at 11:25:24
Phelonious Ponk
Audiophile

Posts: 557
Location: NC
Joined: September 3, 2007
 OMG. Mr. Pott? Meet Mr. Kettle.

P

RE: Problem is it's wrong!!!!!, posted on November 5, 2009 at 15:44:50
Phelonious Ponk
Audiophile

Posts: 557
Location: NC
Joined: September 3, 2007
 I have to sympathize with Gordon, I'm afraid. It's difficult not to shout when local "authorities" are spreading blatant misinformation. Wasn't it Gordon himself who said, the other day, that digital music playback uses gobs of virtual memory? I nearly blew a vein in my head.

P

RE: Problem is it's wrong!!!!!, posted on November 5, 2009 at 22:06:03
fmak
Audiophile

Posts: 4100
Joined: June 1, 2002
 Are you a subscriber; I cannot read it without buying an annual overseas subscriptiopn - >$70?

What does the article say?

RE: Problem is it's wrong!!!!!, posted on November 6, 2009 at 02:09:21
Phelonious Ponk
Audiophile

Posts: 557
Location: NC
Joined: September 3, 2007
 I can't read it either. Evidently it confuses asynch upsampling with asynch USB. Unless Gordon is the one who is confused.

P

RE: Jitter and other topics from Malcolm Hawskford, posted on November 5, 2009 at 00:13:16
fmak
Audiophile

Posts: 4100
Joined: June 1, 2002
 It seems that we are being asked $72 for an annual overseas subscription just to read the article.

I used to take the magazine but contents deteriorated a few years ago and I haven't read it since.

Is there a way to take a single digital issue?

Are the tracks other than the original the residuals and not original audio plus additions?

RE: Jitter and other topics from Malcolm Hawskford, posted on November 5, 2009 at 13:39:16
audioengr
Manufacturer

Posts: 4088
Location: Oregon
Joined: April 12, 2001
 I have asked if they can post it online.

Malcolm Hawskford-Clear Up, posted on November 6, 2009 at 03:21:09
fmak
Audiophile

Posts: 4100
Joined: June 1, 2002
 Does he talk about asybc usb transmission from a PC or it is something from Jan Didden?

It would be good to have a brief summary of what is said about jitter.

RE: Malcolm Hawskford-Clear Up, posted on November 6, 2009 at 12:54:47
audioengr
Manufacturer

Posts: 4088
Location: Oregon
Joined: April 12, 2001
 I cant quote the article without permission, but the ideas are:

1) S/PDIF and AES jitter is usually pattern-based (music-correlated) and not random
2) Jitter can also be related to power supply ripple PS noise and clock signals.
3) the nature and spectra of the jitter are important, not just some single magnitude measurement

RE: Malcolm Hawskford AES Paper, posted on November 6, 2009 at 08:37:00
Slider
Audiophile

Posts: 445
Location: NoCal
Joined: September 24, 2006
 While I haven't seen it, any async talk would probably be by Didden, who authored the article. I believe the audio samples are derived from Hawksford's AES paper from a couple years ago, and the article likely summarizes it and includes some interview text. The paper is very good, with a broad overview of both random and periodic jitter, including correlated types of periodic jitter, and some limited discussion of design techniques to minimize. You can download the AES paper here. Below is the Introduction ...



INTRODUCTION
This paper explores the area of jitter with a particular bias towards high resolution systems. Earlier work [1- 8] has identified sources of jitter (which are well known) and also developed the mathematics which explains how jitter distorts a signal. Although jitter is not a fundamental distortion such as the errors derived from an incorrectly dithered quantizer [9], nevertheless it is pervasive in digital audio systems where to some degree all systems are defective in this area. Indeed in a high resolution system, distortion resulting from jitter can be more significant than quantizer distortion especially for systems using more than 20-bit resolution. One of the major difficulties in quantifying and explaining the consequences of jitter is that there are many sources of jitter. Also, jitter can be classed into three basic forms (all can coexist) where there can be Periodic jitter-related artifacts are further complicated as they can be linked, for example, to mains hum as well as the various clock signals present within equipment. Also, there can be correlated elements with the actual digital signals carrying the audio information. All these inter-related dependencies complicate the interpretation of jitter making it difficult for a simple jitter estimate or spectrum to be interpreted in terms of its subjective consequences.

As well as the numerous sources of error, the system architecture itself can influence the way jitter affects the resultant audio signal. For example, the use of noise shaping and up-sampling [10] with linear pulse code modulation (LPCM) alters the spectrum of the jitter induced distortion. Whilst, as suggested in an earlier paper [11], the use of a multiplying digital-to-analogue converter (DAC) with a raised cosine reference signal can in certain circumstances reduce distortion and HAWKSFORD JITTER SIMULATION augment interpolation between samples prior to the lowpass filter reconstruction filter. There are also analogue amplifiers which when processing a sampled-data signal can produce distortion akin to correlated distortion [12]. Finally, the choice of 1-bit sigma-delta modulation (SDM) code [13], pulse-width modulation (PWM) code [14] or multi-level LPCM code [15] changes the nature of jitter distortion.

As well as presenting comparative discussion on these numerous system options/permutations the subject of jitter is approached from the perspective of simulation. A technique is discussed that shows how by applying the defining mathematics, the true jitter distortion can be extracted such that it can be auditioned to enable its sonic signature to be identified. The jitter simulator is defined so that it can operate at the native sampling rate of the system and also avoid problems of high frequency aliasing distortion that result from distortion products being generated “between samples”. The paper presents both a broad review of jitter mechanisms in relation to typical audio system formats and architectures and also describes the simulator in detail. Time domain and spectral examples are derived using an actual music sequence and 3-D spectral plots presented as a function of time and frequency to illustrate the relationship between signal and various forms of jitter.

This work is considered timely when seen in the broader context of high resolution audio systems. As such it demonstrates the importance of minimizing jitter if the true performance of a format is to be realized. It also seeks to identify whether there are significant performance differences when using various system architectures which consequently impact upon not only DAC systems but also on switching amplifiers using SDM signals. Finally, the paper attempts to make some system-level observations that may prove helpful to the designer especially those aspects interlinking digital with analogue circuitry.

RE: Malcolm Hawskford AES Paper, posted on November 6, 2009 at 09:27:30
fmak
Audiophile

Posts: 4100
Joined: June 1, 2002
 Thanks

I know the paper and thought as you did about Didden but tried to draw this from audioengr who has read the article.

Jitter!!....Slowly I turned, step by step, inch by inch...., posted on November 4, 2009 at 16:24:34
Dynaudio_Rules
Audiophile

Posts: 5594
Location: Georgia
Joined: April 1, 2005
 I tell ya, all this talk about jitter is driving me crazy...its like herpes, never can truly get rid of it...just have to learn how to manage with it and minimize its outbreaks.



Scrutiny Strengthens The Truth and Breaks Down Lies 音楽は天国と地球のかけ橋
These guys have the answer., posted on November 5, 2009 at 06:46:14
Mercman
Audiophile

Posts: 2001
Joined: October 20, 2002



RE: These guys have the answer., posted on November 5, 2009 at 12:52:18
Phelonious Ponk
Audiophile

Posts: 557
Location: NC
Joined: September 3, 2007
 I'm pretty sure Larry hears jitter...

P

RE: These guys have the answer., posted on November 5, 2009 at 13:08:28
cfmsp
Audiophile

Posts: 353
Joined: October 21, 2006
But apparently Curly doesn't, perhaps after a little ear-twisting he will?

:)

clay

RE: Jitter!!....Slowly I turned, step by step, inch by inch...., posted on November 5, 2009 at 03:22:55
Phelonious Ponk
Audiophile

Posts: 557
Location: NC
Joined: September 3, 2007
 Wouldn't that be "slowly I turned...step by step...bit by bit..."

"I hear jitter, people..."

P

RE: Jitter!!....Slowly I turned, step by step, inch by inch...., posted on November 4, 2009 at 22:02:07
fmak
Audiophile

Posts: 4100
Joined: June 1, 2002
 Having gone thru this bits are bits RBCD is best stuff, there is nothing else to blame but jitter - even newly invented forms likle SOFTWARE jitter.

RE: Jitter and other topics from Malcolm Hawskford, posted on November 4, 2009 at 13:24:36
TubeDriver
Audiophile

Posts: 65
Location: DC
Joined: February 16, 2007
 Thanks. Can you post a quick description of the various tracks?

RE: Jitter and other topics from Malcolm Hawskford, posted on November 4, 2009 at 14:18:05
audioengr
Manufacturer

Posts: 4088
Location: Oregon
Joined: April 12, 2001
 Track 0 - unchanged track
Track 1 - TPDF (Triangular Probability Distribution Function) noise-based jitter
Track 2 - 2 equal-amplitude sinewaves (44050Hz and 44150Hz)
Track 3 - 3 sinewaves - 50Hz, 100Hz and 150Hz, amplitudes 1, 0.5, 0.25.
Track 4 - sinewave .2Hz
Track 5 - sinewave 10Hz
Track 6 - 3 equal amplitude, 1Hz 50Hz, 44104Hz
Track 7 - Tracks 1-6 combined

Steve N.

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