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R/E/P => R/E/P Archives => Dan Lavry => Topic started by: obyone on October 03, 2006, 10:32:16 PM

Title: Digidesign White Paper
Post by: obyone on October 03, 2006, 10:32:16 PM
Hi guys,

I am surprised that no one has mentioned anything about the new white paper that digidesign have posted on their website about clock and jitter (in the news section).

If you do have time to read this Dan, I would love to get your comments about it!

Kind Regards!!!

Denis
Title: Re: Digidesign White Paper
Post by: Ronny on October 04, 2006, 09:15:02 AM


I quick read it, well more like scanned it, my first impression was that it was an honest and well written article and I didn't notice anything that was off base nor speculative and even counter speculative. They even say that the 192k internal clock can have more jitter than clocking from an external in some cases. I find the conclusion section to mirror the views of many folks on this forum. The writer of the article obviously knows that psychoacoustics play a key role in misevaluating audio gear. He doesn't come right out and say it, but I get the impression that he knows there is a lot of hype from manufacturers that rely on power of suggestion and not always totally false, but round about or misleading information to sell their wares.

Here's the direct link, to save time searching the site.

http://akmedia.digidesign.com/news/docs/WhitePaper_ClockJitt er_30863.pdf

 
Title: Re: Digidesign White Paper
Post by: Etch-A-Sketch on October 13, 2006, 05:58:00 PM
I read the paper, and was under the impression that they were saying the 192 will have higher jitter when using an External clock, not that it has a higher jitter than other external clocks...
Title: Re: Digidesign White Paper
Post by: Ronny on October 14, 2006, 07:47:50 AM
Etch-A-Sketch wrote on Fri, 13 October 2006 17:58

I read the paper, and was under the impression that they were saying the 192 will have higher jitter when using an External clock, not that it has a higher jitter than other external clocks...



I said "in some cases" and was referring to page 13 quoted from:  

http://akmedia.digidesign.com/news/docs/WhitePaper_ClockJitt er_30863.pdf


"dedicated clocks use non-PLL’ed XOs and can have lower amounts of jitter compared to the 192’s PLL’ed internal clock. But since all sources pass through the 192’s PLL, all clocks assume a similar spectrum above the loop filter corner frequency."
Title: Re: Digidesign White Paper
Post by: Socrates on October 14, 2006, 06:52:47 PM
Its been a long time since I discussed such matters, but I recall that the cable from the dedicated external clock can introduce jitter of its own....
Title: Re: Digidesign White Paper
Post by: Ronny on October 15, 2006, 05:32:23 AM
Socrates wrote on Sat, 14 October 2006 18:52

Its been a long time since I discussed such matters, but I recall that the cable from the dedicated external clock can introduce jitter of its own....


True, I'm in Dan's camp as far as clocking from outboard sources, it's really only needed when linking multi-devices. I've always thought that clocking from the source of the audio made more sense and in the olden days, it provided a more stable system for most of my apps involving only 2 or 3 devices in the clock chain.
Title: Re: Digidesign White Paper
Post by: danlavry on October 17, 2006, 02:57:24 PM
Ronny wrote on Sun, 15 October 2006 10:32

Socrates wrote on Sat, 14 October 2006 18:52

Its been a long time since I discussed such matters, but I recall that the cable from the dedicated external clock can introduce jitter of its own....


True, I'm in Dan's camp as far as clocking from outboard sources, it's really only needed when linking multi-devices. I've always thought that clocking from the source of the audio made more sense and in the olden days, it provided a more stable system for most of my apps involving only 2 or 3 devices in the clock chain.



If you look at page 8, upper right (digidesign article) it says:

"Internal clock provides the lowest jitter in a single interface system".  

So the digidesign article supports what I have been saying.
The article states a lot of other facts that I have been saying for a long time, though I was not mentioned in the bibliography of that paper.

It would have been great to have Digidesign support a year ago, during my back and forth with that "other company" that makes clocks. I did not really expect Digidesign support, given all that I said about 192KHz, which they were selling at the time.

It would be worth noting that the new digidesign product, the Venue, is basically a 48KHz rate unit. It certainly does not support 192KHz. How does Digidesign explain it? I guess I will have to wait a year or 2 (similar to the clocking issue) for them to come around with a paper stating that 192KHz is not really needed, again, rehashing all that I said as if it were discovered by them.

Meanwhile, all my efforts regarding proper clocking ended at Saloon. My technical comments, posts and graphs are surrounded by posts about drunk monkeys and political junk.

One PSN moderator put the thread back on my forum, and the next day another moderator put it in Saloon. I consider putting the thread in Saloon very offensive. PSN has been ignoring the emails regarding the matter.


You can see the "Proper Word Clock Implementation" thread at Saloon:
http://recforums.prosoundweb.com/index.php/m/23134/1684/?src h=dan+lavry#msg_23134  

Regards
Dan Lavry
http://www.lavryengineering.com
Title: Re: Digidesign White Paper
Post by: danlavry on October 19, 2006, 01:45:40 PM
danlavry wrote on Tue, 17 October 2006 19:57

Ronny wrote on Sun, 15 October 2006 10:32

Socrates wrote on Sat, 14 October 2006 18:52

Its been a long time since I discussed such matters, but I recall that the cable from the dedicated external clock can introduce jitter of its own....


True, I'm in Dan's camp as far as clocking from outboard sources, it's really only needed when linking multi-devices. I've always thought that clocking from the source of the audio made more sense and in the olden days, it provided a more stable system for most of my apps involving only 2 or 3 devices in the clock chain.



If you look at page 8, upper right (digidesign article) it says:

"Internal clock provides the lowest jitter in a single interface system".  

So the digidesign article supports what I have been saying.
The article states a lot of other facts that I have been saying for a long time, though I was not mentioned in the bibliography of that paper.

It would have been great to have Digidesign support a year ago, during my back and forth with that "other company" that makes clocks. I did not really expect Digidesign support, given all that I said about 192KHz, which they were selling at the time.

It would be worth noting that the new digidesign product, the Venue, is basically a 48KHz rate unit. It certainly does not support 192KHz. How does Digidesign explain it? I guess I will have to wait a year or 2 (similar to the clocking issue) for them to come around with a paper stating that 192KHz is not really needed, again, rehashing all that I said as if it were discovered by them.

Meanwhile, all my efforts regarding proper clocking ended at Saloon. My technical comments, posts and graphs are surrounded by posts about drunk monkeys and political junk.

One PSN moderator put the thread back on my forum, and the next day another moderator put it in Saloon. I consider putting the thread in Saloon very offensive. PSN has been ignoring the emails regarding the matter.


You can see the "Proper Word Clock Implementation" thread at Saloon:
 http://recforums.prosoundweb.com/index.php/m/23134/1684/?src h=dan+lavry#msg_23134  

Regards
Dan Lavry
http://www.lavryengineering.com


Does anyone have any comments regarding the above post?

Regards
Dan Lavry
http://www.lavryengineering.com[/quote]

Title: Re: Digidesign White Paper
Post by: bushwick on October 19, 2006, 02:21:22 PM
My only question is, how can a moderator's posts be moved by another moderator? If that is the case, there is something really crap goin on here. Who would do that and why? Is this a mistake?

joshua
Title: Re: Digidesign White Paper
Post by: bblackwood on October 19, 2006, 02:39:54 PM
bushwick wrote on Thu, 19 October 2006 13:21

My only question is, how can a moderator's posts be moved by another moderator? If that is the case, there is something really crap goin on here. Who would do that and why? Is this a mistake?

No, only Admin can move threads around like that. Fletcher explained it to Dan fully, if he has questions, he should contact Fletcher privately.
Title: Re: Digidesign White Paper
Post by: PookyNMR on October 19, 2006, 02:45:34 PM
danlavry wrote on Thu, 19 October 2006 11:45

Does anyone have any comments regarding the above post?


I do find it encouraging to see manufacturers put forth more honest scientific disclosures - especially if it means that end users end up with turley better products.

I was involved is some of the threads that you mention, Dan.  It's a bit sad they're in the 'Saloon' as there was a wealth of great technical information that many of us learned a great deal from.  Wherever that info is now, it's just great that it's still available for others to learn from.  Personally, I was most saddened when I tried to re-read the thread to re-learn and at one point found the thread missing from PSW.

Title: Re: Digidesign White Paper
Post by: danlavry on October 19, 2006, 06:35:16 PM
bblackwood wrote on Thu, 19 October 2006 19:39

bushwick wrote on Thu, 19 October 2006 13:21

My only question is, how can a moderator's posts be moved by another moderator? If that is the case, there is something really crap goin on here. Who would do that and why? Is this a mistake?

No, only Admin can move threads around like that. Fletcher explained it to Dan fully, if he has questions, he should contact Fletcher privately.


Hi Brad,

Here are the facts:

The removal of the thread WAS coupled with a message from a PSN stating "moved by moderator". This was on a forum where I am a moderator, and I did not post it. I accept that it was an un intentional error on the part of PSN. It was corrected, so I have no issue with that.  

When you reposted this thread, it was removed within a day and put in Saloon. No one told me about it. There was no discussion at all, and Fletcher did NOT say anything to me about it. No discussion, he just did it.

Priscilla and I sent at least 4 emails to Fletcher, stating how displeased I was to the thread posted in Saloon, and what we wish will be done.  

We recieved NO REPLY!

Regards
Dan Lavry
http://www.lavryengineering.com

Title: Re: Digidesign White Paper
Post by: Fletcher on October 19, 2006, 08:35:56 PM
Because no reply was necessary.  

Do you really want to get into this on your forum or would you like to get back to the business of discussing audio [the purpose of these forums].

As I mentioned in my PM [Private Message] to you earlier today, if you have a problem with this pick up the phone and give me a call.  I do not respond to spousal emails concerning forum matters.

I would also suggest you delete this post, and all posts that are not audio related... but its your forum, do as you like [within reason].

Peace.
Title: Re: Digidesign White Paper
Post by: Sin x/x on October 19, 2006, 10:19:48 PM
danlavry wrote on Thu, 19 October 2006 12:45



Does anyone have any comments regarding the above post?

Regards
Dan Lavry
http://www.lavryengineering.com


Censorship can never be a good thing.



In the long run truth will prevail.
Title: Re: Digidesign White Paper
Post by: Ronny on October 20, 2006, 01:40:11 AM

"Censorship can never be a good thing."

Exactly.

Not only does PSW censor members that don't post agreeable posts to the moderators, but they delete some of the moderators posts when they aren't agreeable with the owners. We aren't dumb asses, we know that you make money on the advertising and over cater to some manufacturers who pay the bills. It's obvious what's been happening for quite a while now.

It's a big problem PSW, you should look into it as the truth in audio is more important than any product that you may lose revenue on, just because others in the audio industry may pan it. I feel that you should look at it as a good reason to re-examine your own views, but obviously my single opinion doesn't mean jack.

The Lavry forum is the last one on PSW that I monitor for this reason, so lose another click through customer, I won't go to the Saloon to read what should be kept on this forum. I'll look at it once again after you delete this post, as PSW is not a fair and unbiased newsgroup base and I'll reserve myself to reading Dan's expert take on what's really happening in audio, on his website where the issue of censorship would never exist, even at the detriment of market PR on his own products.

They can never rob you of your honesty and struggle for truth in audio Dan Lavry, they can only attempt to postpone it.

Title: Re: Digidesign White Paper
Post by: Fletcher on October 20, 2006, 08:02:58 AM
Ronny wrote on Fri, 20 October 2006 01:40


"Censorship can never be a good thing."

Exactly.

Not only does PSW censor members that don't post agreeable posts to the moderators, but they delete some of the moderators posts when they aren't agreeable with the owners. We aren't dumb asses, we know that you make money on the advertising and over cater to some manufacturers who pay the bills. It's obvious what's been happening for quite a while now.


Actually Ronnie, I didn't want to get into this, especially on this forum because this is a non-tchnical topic [which in my opinin is best suited for the "Saloon"... but that is my opinion and we will leave this quandary in the hands of this forum's moderator as to the disposal of this thread].

Let's hit the "rewind" button for a couple of minutes and look back to the formation of PSW's recording forums back in like 2001.  

I was contacted by Ken Berger who at the time was the owner of PSW to put together a set of recording forums.  I took the challenge for a monthly stipend and complete autonomy.  I received an adequate stipend, and the complete autonomy [which to me was actually more important than the stipend part but I wasn't set to tell that to management at that point, and seeing as I had both all was good].

Within a year we built a pretty good environment.  We had "Mixerman" and "Harvey Gerst", "John Klett" and "Seva".  We were able to build a site that was based around the community that at the time was indeed "professional audio".

Time went by and the infamous "Mixerman Diaries" lifted the fame and I dare say infamy of the old "recpit" to the point where in January of '04 it was decided that the recording forums had to split.  1/2 of the "recpit" became "MARSH" led by "Mixerman" and his crew.  Its a pretty cool site on the more social aspects of what we do.  It is a place where there is a social order and structure which R/E/P doesn't have where mud can be slung with out penalty nor much backup from the management of that section of the website.

When the "recpit" split R/E/P was formed as a more technically oriented site where decorum was not only expected but enforced.  When George Massenburg first opened his forum he had a pretty strict policy that you had to include your name and professional affiliation to post.  Anyone could read, but to contribute you had to be A) identifiable; B) accountable for your statements.

Klaus Heyne has continued that tradition in what I feel is absolutely the most authoritative forum on the subject of microphones in the world.  Ross Hogarth, Terry Manning, Dave Hecht, Steve Albini, and yes, Mr. Lavry have produced what I would like to think are the most civil and authoritative set of audio production forums available on the internet.  These forums are indeed about facts and opinions that have a basis in fact more so than myth.

What happened with the original thread was that Mr. Lavry decided to edit several posts made by Lucas (sp?) from Apogee Electronics.  Now Lucas is also a respected design engineer, he too should have had the ability to voice his full statements without interdiction from the forum's moderator.  This did not happen, which in my opinion diluted the value of the thread in question because of the censorship of a view that opposed Mr. Lavry's view.

Whether Lucas's words were spot on or not is a matter for greater minds than mine to decide.  It is my job and position to see that those words were available in the thread as this site, and these forums are to enable open discourse on any topic by those qualified to make those comments.  It was indeed Mr. Lavry's censorship of the fore mentioned statements that prompted not only the closure of the original thread [by me] as well as the thead's subsequent repositioning in "The Saloon".

Had Mr. Lavry refuted the statements with his own words and not the reactionary censorship of the words of a colleague this discussion would never have taken place.  

When Mr. Lavry was added to the R/E/P forums I took a tremendous amount of pressure from several manufacturers as well as one of our former moderators and would not waiver on my stance that Mr. Lavry had a right to be heard.  When Mr. Lavry edited the posts of a fellow designer that poisoned the thread in my opinion, which meant that the thread was no longer of fact but skewed in a manner that only supported Mr. Lavry's position.  Right or wrong, all voices should be heard on these forums in their entirety or these forums become nothing but a shill point for their moderator's firm.  I won't permit that on my own forum, I will not permit that on any other forum on the R/E/P board.

To this day, my stipend, while greatly reduced from what it was when we started this project is still in tact.  To this day my autonomy on these decisions is still mine and mine alone.  I have people with whom I consult on these matters, like Mr. Blackwood my co-administrator, but when the rubber meets the road these decisions are mine and mine alone.  The buck stops here.

I do not bend to threats from manufacturers [of which there have been many], I do not bend to threats from moderators [of which there have been fewer than those from the MFG's but they have existed none the less].  I enjoy full support for my decisions from the upper management of the PSW site and its parent company Huge Universe Inc. [which I think was just sold but it doesn't affect me or our forums in any manner other than the neat little symbols that now accompany each forum].

Again, this kind of bullshit has absolutely no place on a technical forum such as Mr. Lavry's.  Y'all requested an explanation so an explanation is what you have received.  This is indeed an abridged version of that explanation but suffice it to say that there are absolutely no commercial motives in any of my decisions as it applies to the administration of these forums.

Peace.
Title: Re: Digidesign White Paper
Post by: Tom C on October 20, 2006, 09:13:32 AM
Fletcher, is the version down in R/E/P Saloon the censored
or the uncensored one?
Title: Re: Digidesign White Paper
Post by: bblackwood on October 20, 2006, 09:19:46 AM
Tom C wrote on Fri, 20 October 2006 08:13

Fletcher, is the version down in R/E/P Saloon the censored
or the uncensored one?

It's the edited one - once the posts are edited, the info is gone.
Title: Re: Digidesign White Paper
Post by: Brent Handy on October 20, 2006, 12:47:07 PM
danlavry wrote on Tue, 17 October 2006 19:57

It would be worth noting that the new digidesign product, the Venue, is basically a 48KHz rate unit. It certainly does not support 192KHz. How does Digidesign explain it? I guess I will have to wait a year or 2 (similar to the clocking issue) for them to come around with a paper stating that 192KHz is not really needed, again, rehashing all that I said as if it were discovered by them.


The Venue is a live sound platform.  There are no common sense audio quality reasons to go above 48.  Consider the environment, speaker system limitations and concert SPL/human ear masking effects.

The Venue is set up to interface with PT HD, so in my case, where I am capturing audio for video (Avid, which uses 24bit/48kHz AIFF), I require no extra math processing.

There are a couple 96kHz consoles, but I think that it is a waste.  Any sonic or processing advantages are going to be lost in a PA system operating at 10-20% THD, in the average shed, stadium, etc.
Title: Re: Digidesign White Paper
Post by: danlavry on October 20, 2006, 02:59:37 PM
Fletcher wrote on Fri, 20 October 2006 13:02

Ronny wrote on Fri, 20 October 2006 01:40


"Censorship can never be a good thing."

Exactly.

Not only does PSW censor members that don't post agreeable posts to the moderators, but they delete some of the moderators posts when they aren't agreeable with the owners. We aren't dumb asses, we know that you make money on the advertising and over cater to some manufacturers who pay the bills. It's obvious what's been happening for quite a while now.


What happened with the original thread was that Mr. Lavry decided to edit several posts made by Lucas (sp?)...

When Mr. Lavry edited the posts of a fellow designer that poisoned the thread in my opinion, which meant that the thread was no longer of fact but skewed in a manner that only supported Mr. Lavry's position.  

Peace.



Fletcher,

First. you said that you do not respond to spouse’s emails. I sent you an email which you did not respond to, telling you how I feel about moving the thread to Saloon. When you did not respond, I asked, Priscilla, the CEO of Lavry Engineering to help. You did not respond to my emails, and you did not respond to mine.  

Now you wrote a long post repeating over an over that I censored Lucas (Apogee engineer). That is NOT TRUE! I did not censor any of Lucas statements!!! In fact, at some point I censored Max (Apogee sales and marketing) because he was just being offensive. I told Max to have apogee engineering come in and state thier position. I AM THE ONE THAT INVITED Lucas (or any Apogee engineer) in, and Lucas was NEVER CENSORED!

So all your long argument is based on a wrong premises.

And then you said: “When Mr. Lavry edited the posts of a fellow designer that poisoned the thread in my opinion”.  

That is wrong. And BTW as a moderator, I do not have the access to edit other posters massage! I CAN DELETE a post, but I CAN NOT EDIT the content of a post. You Fletcher, should have known that "little technical fact", and realized that accusing me of editing posts is wrong.  

Your long thread about how I censored and even edited posts is wrong. YOU are the one that is doing the censoring. You accuse me wrongly for censoring and editing, while you are the one doing it. There is only one proper way to fix it: repost the thread now, without any alterations.

Dan Lavry
http://www.lavryengineering.com
Title: Re: Digidesign White Paper
Post by: bblackwood on October 20, 2006, 03:05:09 PM
danlavry wrote on Fri, 20 October 2006 13:59

And BTW as a moderator, I do not have the access to edit other posters massage! I CAN DELETE a post, but I CAN NOT EDIT the content of a post.

Not true.

From the Admin action-log viewer:
Title: Re: Digidesign White Paper
Post by: danlavry on October 20, 2006, 04:16:58 PM
bblackwood wrote on Fri, 20 October 2006 20:05

danlavry wrote on Fri, 20 October 2006 13:59

And BTW as a moderator, I do not have the access to edit other posters massage! I CAN DELETE a post, but I CAN NOT EDIT the content of a post.

Not true.


Brad,

You are correct. I just checked it out and the edit button is active on all posts. I seem to recall that in the past I could only edit mine (I may be worng).

But BACK TO THE POINT OF DISCUSSION: I have been under the impression that I can only edit mine. I NEVER EDITED ANY POSTS!!! Changing content is like fraud. Fletcher said that I edited posts. I NEVER EDITTED ANY POSTS!  

Regards
Dan Lavry
http://www.lavryengineering.com  
Title: Re: Digidesign White Paper
Post by: Fletcher on October 20, 2006, 05:29:13 PM
I just called Lucas, there was no editing of his posts by Mr. Lavry.
Title: Re: Digidesign White Paper
Post by: Max on October 20, 2006, 06:57:10 PM
While it may be true that Dan did not edit any of Lucas' posts, he did delete a number of posts I had put up to address the issues. I am the spokesperson for Apogee Electronics and anything I say is wholly endorsed by engineering, making the distinction between myself and anyone in our engineering department moot.

In principle, a moderator who is also a manufacturer should not be allowed to delete posts by a competitor that the moderator is attempting to impeach. To do so only imparts bias to the reader and promotes the moderator's agenda at the expense of a fair and open dialogue.

As for this white paper, there is nothing claimed in there with respect to jitter that we at Apogee do not agree with or goes against any of our previous claims. Apogee never stated that Big Ben provided lower jitter than a converter on internal clock. What we did say was that Big Ben can improve performance of many external converters across the quality spectrum.

There are things we tried to express that Dan Lavry and others purposely omit in these clocking arguments. Yes, Jitter is a deficiency that causes a certain type of distortion to the signal. However, the ear, being a non-linear device with respect to frequency, will not hear all jitter the same. It is very easy to create a scenario whereby two signals can be induced with jitter, one of which has significantly more jitter than the other, but sounds audibly more ACCURATE to the ear. The distortion due to jitter on the one with more jitter can be relegated to frequencies that are entirely out of the human audible spectrum in various ways, whereas the other can have far less jitter, but at frequencies that are much more audibly apparent.

It is certainly possible to design an external clock in such a way that the increased amount of jitter that results will have less of an audible impact than the internal clock by itself. For this reason one cannot claim that an internal clock will always be more accurate - merely that it will theoretically always have less jitter. There is a significant difference between the two, and the testimony we have been seeing on the market and in our own testing with respect to Big Ben over the last few years certainly attests to this.

Title: Re: Digidesign White Paper
Post by: bblackwood on October 20, 2006, 07:14:51 PM
Hi Max, to be clear, Dan deleted one post in that entire thread...
Title: Re: Digidesign White Paper
Post by: Max on October 20, 2006, 08:08:13 PM
Actually Dan deleted a number of responses that I posted that were directed at his attacks on Apogee:

danlavry wrote on Tue, 22 March 2005 01:03

Max,

You said: Dan had deleted a number of our responses in this regard, so we have opted not to continue this discussion in his forum.

I deleted some of your repetitive salesman, non-technical responses but none of Lucas's.


Dan also deleted posts by Nika that agreed with Apogee's point of view, and subsequently banned both of us from posting. If you recall Brad, you were the one who reinstated us:

bblackwood wrote on Tue, 29 March 2005 14:18

Well, we're all about free speech here, but sometimes mods have a different perspective than the masses. That being said, Nika has brought up some good points which should be heard.

This will be dealt with, and we thank you all for your thoughts.


bblackwood wrote on Tue, 29 March 2005 18:13

Both Nika and Max have been un-banned.


As to whether my responses were any more repetitive salesman, non-technical responses than Dan's comments about Apogee should have been left up to the reader. Again, a moderator should not be allowed to delete posts by a competitor that the moderator is attempting to paint in a negative light.

And for the record, Apogee has never been an advertiser on Pro Sound Web.
Title: Re: Digidesign White Paper
Post by: bblackwood on October 20, 2006, 11:47:22 PM
Max wrote on Fri, 20 October 2006 19:08

Actually Dan deleted a number of responses that I posted that were directed at his attacks on Apogee:

I can only go on what the Admin action log viewer from the forum software shows me, and that's exactly one deletion in that entire thread. And zero edits.

Thanks,
Title: Re: Digidesign White Paper
Post by: dcollins on October 21, 2006, 02:14:05 AM
Is anyone surprised that external sync was worse?

That would be news.

DC
Title: Re: Digidesign White Paper
Post by: Jon Hodgson on October 21, 2006, 06:42:37 AM
Max wrote on Fri, 20 October 2006 23:57

It is certainly possible to design an external clock in such a way that the increased amount of jitter that results will have less of an audible impact than the internal clock by itself. For this reason one cannot claim that an internal clock will always be more accurate - merely that it will theoretically always have less jitter. There is a significant difference between the two, and the testimony we have been seeing on the market and in our own testing with respect to Big Ben over the last few years certainly attests to this.



But the external clock is not fed directly to the converters is it? It is used to drive a phase locked loop which includes and internal clock, so what you would end up with is the jitter on the external clock, smoothed out by a degree dependant on the quality of the phase locked loop, PLUS the jitter of the internal clock.

So as far as I can see you're not exchanging the jitter of the internal clock for the possibly subjectively superior jitter of the external clock, rather you are increasing the jitter of the internal clock.

Hard to see how this could be in any way more ACCURATE, though some people might find it pleasantly more fuzzy.
Title: Re: Digidesign White Paper
Post by: Jørn Bonne on October 21, 2006, 08:00:54 AM
Max wrote on Sat, 21 October 2006 02:08

Actually Dan deleted a number of responses that I posted that were directed at his attacks on Apogee:

danlavry wrote on Tue, 22 March 2005 01:03

Max,

You said: Dan had deleted a number of our responses in this regard, so we have opted not to continue this discussion in his forum.

I deleted some of your repetitive salesman, non-technical responses but none of Lucas's.


Dan also deleted posts by Nika that agreed with Apogee's point of view, and subsequently banned both of us from posting. If you recall Brad, you were the one who reinstated us:

bblackwood wrote on Tue, 29 March 2005 14:18

Well, we're all about free speech here, but sometimes mods have a different perspective than the masses. That being said, Nika has brought up some good points which should be heard.

This will be dealt with, and we thank you all for your thoughts.


bblackwood wrote on Tue, 29 March 2005 18:13

Both Nika and Max have been un-banned.


As to whether my responses were any more repetitive salesman, non-technical responses than Dan's comments about Apogee should have been left up to the reader. Again, a moderator should not be allowed to delete posts by a competitor that the moderator is attempting to paint in a negative light.

And for the record, Apogee has never been an advertiser on Pro Sound Web.


I was one of the people who followed the wordclock thread in Dan's guest forum. I also posted once, supporting Max's and Lucas's rights to rectify some of the desinformation being launched against Apogee product.

I was stunned to see a guest moderator yelling at people at length using caps for long sections, continously putting down a competing company's products, their "young engineers", "sales people" etc. and all the while promoting himself and his own product.

The interesting thing was that he got away with it!!! Neither Fletcher nor Brad seemed to mind this utter lack of moderating skills on PSW. On the contrary, soon after Dan was promoted and had his own permanent forum.

I have noticed that Dan's moderating skills have improved somewhat since, though!

I posted a comment on Dan's behaviour in a thread on PSW where this was discussed. I think it was on Fletcher's forum, if memory serves. And yes, my post was deleted immidiatly after I posted it, as this one may well be.

Like Ronny said, Dan's forum is down on my list of priority, though it does offer interesting stuff from time to time.

J
Title: Re: Digidesign White Paper
Post by: danlavry on October 23, 2006, 06:49:36 PM
Max wrote on Fri, 20 October 2006 23:57

While it may be true that Dan did not edit any of Lucas' posts....


You said:
“There are things we tried to express that Dan Lavry and others purposely omit in these clocking arguments.”

Not so. What you propose here is a new argument, and I am responding to it. This is the first time I have heard this argument (why?)

The last argument we heard from engineering stated:

(DEC 27 2004)
“We do CLAIM:
1. The Big Ben is an excellent low jitter solution if you need a master clock
2. If you have a clock to a very jittery source, you’ll get better results most of the time by having the Big Ben cleaning it up first
We haven’t claimed anything else.

Lucas van der Mee
Sr. design Engineer
Apogee Electronics”


Soon after the above was posted, I considered the argument settled.

Now we have a new argument claiming that one can have some “special jitter” to make things sound better in most converters. Let’s examine it:

Different AD and DA’s (IC’s) respond to jitter in different ways. The audible effect of jitter on the reproduced signal depends on the choice of IC (modulator over-sampling ratio, modulator number of bits, and more. There is literature out which discusses this in depth).

Next, the “inserted jitter” needs to go through a PLL on its way to the converter IC. PLL’s (and thus their reaction to jitter) also vary a lot from design to design (number of PLL stages, corner frequency…) .

The argument says:  “It is very easy to create a scenario whereby two signals can be induced with jitter, one of which has significantly more jitter than the other, but sounds audibly more ACCURATE to the ear.”

Even those that wish to argue that jitter “improves” sound, must restrict their arguments to altering specific signals. The argument is wrongly extended to a claim that jitter can improve any signal without any knowledge of the signal itself. The music is a wave that changes all the time, and the clock box has no access to that signal. It does not even know what is playing.

What is being “blurred” here is the difference between subjective opinions and scientific facts. Also blurred are comments regarding the impact of jitter on specific known signals, and the impact on music (any signal), all leading to the use of the word “Accurate”.  Accurate according to what definition?
And all that is predicated on the wrong assumption that most AD’s will react to the “special” jitter similarly.

But the sales guy says:

1. “It is certainly possible to design an external clock in such a way that the increased amount of jitter that results will have less audible effect…”

It is especially easy to understand that this premise is wrong when you take into account the fact that the clock box does not get to see the music signal. Additional this “special jitter” will go through various types of hardware that will be reacting to this “special jitter” differently in every case.

The new argument does not state “we figured how to do something”. It says “it is certainly possible”. It does not say “we implemented it”.

And then you said:

2. “For this reason one can not claim that an internal clock will always be more accurate…and the testimony we have been seeing on the market and in our own testing… certainly attest to that.”

Why are you talking about what one may claim or not claim? We are talking about what you have inside your product, by design (hardware, firmware, software…)  

And here is your previous argument: (Proper Word clock implementation thread, Oct 27 2004)

“The problem with discussing the how and why of Apogee's advanced science in this field is that there are things we are doing that we do not want to advertise to our competitors…”

This suggests a scenario such as:

There was jitter research project resulting in some certain type of jitter (intentional timing error in capturing the signal), that when inserted by way of external clock circuitry into most converters, makes them sound better. The insertion of such intentional jitter improves any audio signals across the board; it does not require any analysis of the audio signal itself.  
The “special jitter” was implemented in such a way that inserting the same “intentional timing errors” would improve sound regardless of and without any knowledge of:
1. The music being played
2. The type of converter IC
3. The clock signal path implementation (PLL)
4. Other sources of jitter

The Engineer was stating that the box will remove jitter (from sources external to the clock), which is a very reasonable clock maker’s goal. The salesman is talking about their “advanced science” resulting in adding more jitter of a certain type to do the impossible.

Should we disregard the original engineer’s statement of DEC 27 2004 or your statement-

“I am the spokesperson… and anything I say is wholly endorsed by engineering, making the distinction between myself and anyone in our engineering department moot.”

Dan Lavry