Home » Guest Moderator Archives » Dan Lavry » Proper word clock implementation
|
| Re: Proper word clock implementation [message #53210 is a reply to message #22983 ] |
Tue, 22 March 2005 09:31   |
 bananahill
Messages: 20
Registered: January 2005
Location: Los Angeles |
Member |
|
|
OK, no listening, just theory...
The cat...
Big Ben (or any external clock) cannot work. It does not make a system or converter sound better.
The box...
double blind listening test.
put the cat into the box and send it into space... the internet.
when does this cat die?
As long as you never listen, you can believe the cat is still alive.
However if you open the box...
If you don't want to listen, then there is no point to any of this.
I understood the point of this forum is to reach a deeper understanding of how this stuff works. The theory is all great in the design stage. Once the product is made, you must use it. To use it, you must listen to the conversion.
If all you want to do is look at waveforms on a scope, then do not sell something as a musical product! Sell it as test equipment!
The point of a deeper understanding of our technology should lead to the end target...music sounds better!
Shouldn't a technical discussion include the FUNCTION of the equipment in question?
Stephen Krause
|
|
|
| Re: Proper word clock implementation [message #53231 is a reply to message #53210 ] |
Tue, 22 March 2005 11:10 |
chap
Messages: 16
Registered: June 2004
Location: CT |
Member |
|
|
I Can't believe I'm taking time out of a busy day for this but since the bullshit is flying........
Dan,
Having re-read this entire thread, I do not see the relevance of your "technical questions" to what Apogee is saying. I also do not agree that the message has in any way been watered down. Seems to me you are using a very selective process when drawing conclusions regarding what Apogee is saying. For example, just because their position is based on listener experience, does not impeach the comments about the technology in Big Ben, rather, it supports them.
I think the real bullshit here is trying to have a theoretical argument about something you have no experience with. I and all my friends, golden eared engineers with thousands of hours spent doing this for a living, with award after award hear exactly what Apogee is claiming. Do you think Apogee's "bullshit" is so powerful that the likes of Sterling Sound, myself (3 Emmy's this year, 3 Billboard charting CDs), Manny Marroquin (2 grammys this year) and the hundreds of other high profile engineers with Big Ben have been hypnotized into believing in a placebo? This is our livelihood! we use what makes us better at our jobs and Big Ben makes the process of recording and mastering better in the ways Apogee described. I understand this does not jive with your personal bias against Apogee (yes, it's that obvious) but you are dong the audio community on this forum a disservice by not being open to the possibility that what we hear is what we hear and not some group hypnosis caused by good marketing.
As for the AD500 and DA1000...they were very good in their day, but nothing compared to even the Mini-Me today, which I understand you had nothing to do with. Those of us that buy Apogee products do so because they sound the best, not because they are marketed the best. My AD8000SE's (I think you approved of them) were saved by Big Ben. I have used your products and have a great repect for you as a designer but you are not the only designer and you have shown a personal disrespect towoards guys like Lucas who are peers and equals. It only detracts from your message. There is no snake oil here, just solid, forward thinking engineering. Should this thread be retitled to 'Apogee Bash"?
chap
|
|
|
| Re: Proper word clock implementation [message #53244 is a reply to message #53231 ] |
Tue, 22 March 2005 11:59 |
danlavry
Messages: 997
Registered: April 2004 |
Gold Member |
|
|
| chap wrote on Tue, 22 March 2005 17:10 |
Dan,
Having re-read this entire thread, I do not see the relevance of your "technical questions" to what Apogee is saying...
....There is no snake oil here, just solid, forward thinking engineering.
chap
|
Chap,
Many of your messages in various chat rooms on ProSound web show your commitment to Apogee gear. You are indeed entitled to your opinion. We would like to have some technical input from you to backup your opinion. We are about technological depth here. Your last comment, similar to Max’s seems to be an attempt to marginalize technological discussion in favor of opinion.
It is not my fault that Apogee's unhappy customers come to my site to vent out their frustrations. I and others have been accused of having an anti Apogee sentiment. The fact is: I have done my best to be fair. After Lucas dropped his previous claims and stated indirectly that they do not claim their clock will improve an AD, I stopped talking about their clock.
I wonder how long and how far you are willing to stand your ground.
In this forum I have a thread about cables. In there are a lot of unbelievable claims about cables, ranging from “magic numbers” to “paralleling a 12AWG cable for the bass and a 14AWG for the highs”. All have some things in common: They call themselves innovative, and they claim to yield the best sound some post comments from satisfied customers, or rave reviews from a magazine. Of course we all know that repeating how innovative and creative a product is does not make it so.
Example 1:
On the cable thread, there is a guy who claims to have invented a “quantum purifier” that grabs the electrons and makes them go at extra speed, to shake the noise out….
Should anyone even bother to try and listen to his cable? As far as I am concerned, a transaction where one guy sells a Quantum purifier cable to another should result with the buyer in the crazy house and the seller behind bars.
Example 2:
A MARKETTING COMPANY “X” sells cable that they claim are: ULTRA LOW JITTER CABLE and TEMPERATURE COMPENSATED CABLE. I do not know what temperature compensated cable means but I KNOW that THE CONCEPT OF “ULTRA LOW JITTER CABLE” is not true. Cables don’t have jitter . A cable is a PASSIVE device. It is just a “piece of material”. The level of jitter is determined by the electrical signal driving the cable! There may be other factors (variable load, induced noise and more). One thing for sure: but there is no such a thing as ultra low jitter cable.
“Jitter to cable” is like a “laptop to Moses”
“Jitter to cable” is like a “Pistachio nut to a whale”
“Ultra Low jitter cable” is like “super high speed tree”
“Ultra Low jitter cable” is like “butter to a headphone jack”
Guess who the marketing company X is? Apogee with their “ULTRA LOW JITTER CABLE”.
Folks, we have the double whammy solution. A clock box that was touted as “the cure for the jitters” (which is not being claimed explicitly any longer, only indirectly) and the “ultra low jitter cable”.
At this point, I am adding question # 4 and 5 to Apogee:
4. What the heck is TEMPERATURE COMPENSATED CABLE?
5. HOW DOES A “ULTRA LOW JITTER CABLE WORK”?
a. WHEN YOU DRIVE A ULRAT LOW JITTER CABLE WITH A JITTERY SIGNAL, DOES THE CABLE SUCK THE JITTER OUT?
b. IF THE CABLE IS REALLY LONG, DO YOU GET NEGATIVE JITTER?
c. Is the principle of operation based on quantum jitter suckers, or is it also a top secret of the 21st century that a guy like me does not have experience in.
Please know that in future that statements about personal opinion and marketing will be deleted unless backed up with technical input.
Dan Lavry
Lavry Engineering, Inc.
|
|
| | |
| Re: Proper word clock implementation [message #53297 is a reply to message #22983 ] |
Tue, 22 March 2005 15:54 |
PookyNMR
Messages: 1598
Registered: April 2004
Location: Edmonton, AB, Canada |
Platinum Member |
|
|
I do not doubt anyone that there may be a difference by adding an external clock. Listening preferences aside, I would just like to know exactly what that difference is.
I still have a question that I can't seem to get an answer for.
If there is a perceivable audible difference why could it not be measured and quantified?
If there is a difference in the jitter of the system, why could it not be measured?
I am confused why the lack of technical data. While there are some who don't seem to care about technical data, there are others who do.
Peace.
Nathan Rousu
|
|
|
| Re: Proper word clock implementation [message #53299 is a reply to message #22983 ] |
Tue, 22 March 2005 16:09 |
Joe Crawford
Messages: 107
Registered: June 2004
Location: Shanks, WV |
Active Member |
|
|
OK, this thread has finally gotten my dander up. This is why I went fishin’ a few years back….
Max – you are a true believer… and in your position you have to be. I respect you for it. Your company has a good line of excellent (or almost excellent, this is where it gets subjective) products. And, if you’re like every other high tech company out there, in order to market them, and meet the next quarter’s sales projections, I would imagine your marketing department sometimes stretches the truth, maybe just a little bit, as far as factual engineering is concerned. They probably don’t even know it when they do. This is totally normal in the audio industry as well as most other bleeding edge technology based industries. It has been a generation or two since sales, marketing, and upper level management in high tech companies were staffed with engineers, rather than specialist in sales, marketing, and management (HP got away with it for years until H & P both retired). Just like today’s political parties, every one spins it a little, no one tell the consumer the factual truth anymore. We engineer's just have a problem with spin.
But, if you eventually get curious, everyone calms down, and, I guess, we all recover from this thread, try something. Take you oldest (and most regarded) development engineer (if you still have one other that new grads, and have managed to keep a lead for a few years, and not the engineering manager, he’s probably corrupted already) out for few drinks some night after work and just have an off-the-record talk with him. Ask him his actual opinion of the direction the product line is taking and what he thinks about the current products. If you really get frisky, ask him a few of the questions brought up on this thread. Even run your current marketing liturature buy him. You might be surprised. Of course, if you bully him, you will get just the answers you want. Like everyone else, he probably values his job.
It’s very hard to develop a corporate culture that permits, even encourages, free speech between sales/marketing and engineering. Their “prime directives” are totally different. I would guess that out of the dozen or more high tech companies I worked for in the last 40 years, only one or two has had a good rapport between those groups. At least from my point of view, they were the best companies ever I worked for.
Well, so much for this soap-box…
Joe Crawford
|
|
|
| Re: Proper word clock implementation [message #53306 is a reply to message #53299 ] |
Tue, 22 March 2005 16:28 |
danlavry
Messages: 997
Registered: April 2004 |
Gold Member |
|
|
Max,
AGAIN for the record:
On Monday Dec 27 2004, an Apogee Sr. Design Engineer Lucas said on this thread:
We do CLAIM:
1. The Big Ben is an excellent low jitter solution if you need a master clock
2. If you have to 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.”
My clear technical comments showing that improved performance is technically impossible have not been answered!
Now to the “low jitter cable issue”
You said:
Finally, let it be clear to the end user that you are deceiving them with another semantic argument when making reference to our cables. Of course cables don't lower jitter, but cables do create jitter, some more than others. Apogee's Wyde-Eye cable creates less jitter artifacts than other cables, hence the phrase "ultra low jitter". We did not call it the "jitter free" cable or even the "jitter reducer", so this blatant attack is a deception.
The blatant deception is selling Ultra low jitter cable. Cables have a lot of specs ranging for bandwidth to resistance to capacitance and much more. But CABLES DO NOT HAVE A JITTER SPECS.
Yes you did not call it "jitter free" or "jitter reducer". You also did not call it a “rose garden” or a “frying pan”. But you called it an “Ultra low jitter cable” In trying to regroup you come up with a “rational” that “cables do create jitter”. That is also nonsense. Covering up BS with more BS. To my knowledge Apogee is the only one that claims that cables have jitter specs.
Yes I know, you cannot argue about “Ultra Low jitter cable”. No one can. You don’t have any measurements to show, just the regular SNAKE OIL blended with personal attacks, followed by claims of hearing it better.
ULTRA LOW JITTER CABLE IS SNAKE OIL. No way around it! Oops, you forgot to answer the other question about the "Temperature Controlled Cable".
Dan Lavry
Lavry Engineering, Inc.
|
|
|
| Re: Proper word clock implementation [message #53323 is a reply to message #53306 ] |
Tue, 22 March 2005 19:31 |
crm0922
Messages: 272
Registered: April 2004 |
Active Member |
|
|
| danlavry wrote on Tue, 22 March 2005 17:28 |
Max,
Yes I know, you cannot argue about “Ultra Low jitter cable”. No one can. You don’t have any measurements to show, just the regular SNAKE OIL blended with personal attacks, followed by claims of hearing it better.
ULTRA LOW JITTER CABLE IS SNAKE OIL. No way around it! Oops, you forgot to answer the other question about the "Temperature Controlled Cable".
Dan Lavry
Lavry Engineering, Inc.
|
Dan, if I were to use a piece of zip cord to carry word clock signals, would I experience more jitter on the receiving end of my system? I am asking this question honestly, as the thought that a cable could contribute to jitter issues seems at least reasonable.
If the zip cord is bad news, then would proper impedance and capcitance ratings improve the jitter situation? If so, could Apogee's cable be built with exacting standards that help resolve such issues?
I sure have learned a lot from this discussion, and I don't mind the snapping back and forth. This type of discussion will make everyone's products better, since you know there are people there to question it.
Now I'll refrain from posting to this thread 10 times a day for a little while.
Chris
|
|
|
| Re: Proper word clock implementation [message #53332 is a reply to message #53323 ] |
Tue, 22 March 2005 20:43 |
dpd
Messages: 25
Registered: March 2005
Location: Indiana |
Member |
|
|
Cables can distort the digital waveforms and close up the 'eye pattern' which will have the effect of increasing the bit errors in any subsequent detector. Most detectors are going to clip the incoming waveform, detect the clock and make the 1/0 detection at the mid-bit point, precisely to eliminate the effect of jitter - at least the bit synchronizers I have used do this. (not sure about AES detectors).
But, unless the cable is defective (e.g. intermittent), what mechanism exists in the cable to create jitter? There are no active, noise-inducing, parts of a cable so about all it can do is distort the waveform.
Am I missing something here?
I have no signature
|
|
|
| Re: Proper word clock implementation [message #53364 is a reply to message #22983 ] |
Wed, 23 March 2005 00:35 |
jimbo-baby
Messages: 16
Registered: March 2005 |
Member |
|
|
|
it occurs to me that the "improvements" in sound reported with use of the big ben may be because of what it adds to the signal rather than what it takes away (i think someone used the term "pretty jitter" to describe this). if that's the case, and some people think it does sound better, it is then being used the same way we use a 1073...to colour the sound in a way we think sounds cool. what is the goal of a converter? most people would say transparency. if you don't care about the number crunching and you just dig whatever sounds more ear pleasing, then go with it, and be satisfied. but don't complain about someone like dan, who has every right to question apogee over it's designs, being such a respected designer himself. he's not just bagging them out, he's asking them to explain how exactly their claims are possible. if they have some amazing new technological breakthrough, then they can patent it, and explain it to all. it'd be fantastic to do a blind listening test, but the results should be measured technically as well. that way everyone can make up their own mind. but you'd better beware if you're using a DA which adds it's own "ear pleasing colour" for in the box mixing or mastering, because then you're kind of missing the point of the flat response of your expensive room, acoustic treatment and monitors.
|
|
|
| Re: Proper word clock implementation [message #53500 is a reply to message #53323 ] |
Wed, 23 March 2005 12:55 |
danlavry
Messages: 997
Registered: April 2004 |
Gold Member |
|
|
| crm0922 wrote on Wed, 23 March 2005 01:31 |
| danlavry wrote on Tue, 22 March 2005 17:28 |
Max,
Yes I know, you cannot argue about “Ultra Low jitter cable”. No one can. You don’t have any measurements to show, just the regular SNAKE OIL blended with personal attacks, followed by claims of hearing it better.
ULTRA LOW JITTER CABLE IS SNAKE OIL. No way around it! Oops, you forgot to answer the other question about the "Temperature Controlled Cable".
Dan Lavry
Lavry Engineering, Inc.
|
Dan, if I were to use a piece of zip cord to carry word clock signals, would I experience more jitter on the receiving end of my system? I am asking this question honestly, as the thought that a cable could contribute to jitter issues seems at least reasonable.
If the zip cord is bad news, then would proper impedance and capcitance ratings improve the jitter situation? If so, could Apogee's cable be built with exacting standards that help resolve such issues?
I sure have learned a lot from this discussion, and I don't mind the snapping back and forth. This type of discussion will make everyone's products better, since you know there are people there to question it.
Now I'll refrain from posting to this thread 10 times a day for a little while.
Chris
|
Chris,
First, let me have some fun:
Let us give Max the opportunity to dig a bigger hole!
Say Apogee is right. Say they discovered that there is another physical law to be added to the 5 Maxwell equations. Maybe not, I will be flexible. Say there is some mechanism that makes cables manufacture jitter. That is what Max said is it not?
So in the good old tradition of cable specs, lets come up with a figure for pico second per foot (cables are specified in pF/foot , Ohms/foot, uH/foot…). Say 1psec /foot jitter sounds like a great spec to me (why not, I can pull things out of the air as well as Apogee). So take a zero jitter clock (assuming it is there) and add 100 feet of cable, and you have 100psec jitter.
So that is one more argument leading us to the conclusion that internal clocking is better, and assuming Big Ben has little jitter, 100 feet of cable will do you in. So go for internal clock.
There is still one more problem left. No one is saying what temperature controlled cable is. I thought about it long and hard, trying to figure out what the hack is temperature controlled cable. I figured if I say the wrong thing, I will be accused of deception, but let me give it a try:
There is a hidden oven built around the copper to make sure the electrons are happy. If they get a cold, they may start shaking very fast and when they enter the low jitter PCB trace they will be very jittery. I wonder if the temperature control is solar or nuclear.
That is the best I can come up with, and the sellers of that will not shed any more light on the issue. Until such time, I have the right to mock it. I think the customers have the right to demand an explanation!
Now, that I had my morning fun… to your question
If I carry your argument forward, then resistors make jitter, capacitors make jitter, everything does. Of course passive components do not generate jitter, least of all a cable, a solid piece of copper.
A cable bandwidth, capacitance, resistance, inductance, the skin effect, the proximity effect and the rest of the specs obey the same principles that ALL OF ELECTRONICS does – the 5 Maxwell equations, the laws of physics that govern all electricity and magnetism (which always go hand in hand).
A resistor generates noise. That noise is and the mechanism which generates it is all in line with Maxwell’s equations. There is a mechanism at play that is explainable. Say I build a comparator circuit for word clock detection. I will use resistors. To set a detection point (threshold). If I use higher value resistors, they will generate more noise, and the outcome can be more jittery.
Does that open the door to salesmen to sell low value resistors as "low jitter resistors"?
Each part, be it a resistor, IC, cable… has specific characteristics that are INDEPENDENT of its application. A 10 Ohm resistor is ALWAYS 10 Ohms resistor, be it for audio, instrumentation or just in the stock room all by itself. A 1/4 watt resistor is always a 1/4 watt resistor. I know a lot of things about that resistor and they GO WITH THE COMPONENT. Of course if I dissipate more power than the rating allows, I will fry it. If I only dissipate 1mW in a 250mW device I have huge margin of safety. It does not mean that I can call it high reliability device. IT IS THE WAY I USED IT that made it high reliability.
It would be appropriate to consider the specs that come with a cable. You may want it to be of certain bandwidth, capacitance, shielded, and so on. That is how you put a system together. But to say that the cable makes jitter?
You can say that a system has low jitter because of a list of factors and cable bandwidth may be one of them. Cable shielding may be another. Much of the outcome is about the interaction of different factors such as cable driver characteristics, load, environment noise, grounding. So you cannot attach attributes to a component characteristics, that varies from case to case, from setup to setup.
I can cut a tree and put it on a high speed jet. Does it become a “high speed tree”?
And again, I really want an explanation regarding the meaning of temperature controlled cable. Apogee will not answer me. They are the “Wal-Mart of converters”. There are a lot of ear people in the industry, that do not know much technical. But almost every one knows that there is a thing called jitter and “it is a bad thing”. So you sell them a flawed concept about an external box fixing a problems in another box, and that is a crock. But they push it anyway. Even after their engineer backs off the claims AND HE DID RIGHT HERE ON THIS FORUM. ANYONE THAT CAN READ CAN SEE IT FOR THEMSELVES. Then you add some BS about ultra low jitter temperature controlled … it is really bad for the industry to have people believe in BS.
You see, ear people get to decide what they want, what they hear, what they like. In a sense, everyone is “king” of their own turf. But this forum is technical, and that “equality” does not exist here. Some people are technical gurus and others are totally uninformed. One can have a lot of awards in the ear side and it does not make them technical. One of the difficult challenges for me is to learn to accept that a lot of visitors here are just “used to a different style” where they get to decide everything. A guy came here yesterday talking about his awards and many years of work as if it is the most importent thing for a cable or clock discussion. What about my many years of dealing with the ELECTRONIC aspects of the cable? I have no cable awards. In fact, it is the end of the era where “fat cat club” ruled audio by ear, ignoring technical realities, with technical awards given by name recognition (thus advertising money). Where is it all leading?
The method of advertising crock in audio has been traditionally to drum up some well known names and have them say nice things for you in exchange to something else.
Technical folks are a lot less willing to “just say anything”. But hearing people don’t look at numbers, and they “bend easier”. You can see the discrepancy between Lucas and Max. Lucas came back to a defensible position. Max will not. Perhaps Lucas wishes that his company would have not said that their cable is low jitter temp controlled.
So naturally, all the snake oil in audio comes back to drumming up folks willing to say things about “how it sounds”. You make them believe you are about substance and they will back you up. Some have so much confidence that they do not even bother with a blind test. They have done so for many years, being respected, even reinforced for such behavior.
And now I am here, calling it BS. Yes Max, the equipment salesman from Sweetwater, now at Apogee, has attacked me and I will respond to it in the next few days. I am still here, at almost 60 years of age, after designing lots of gear for my own and various companies and making a very good living, with very appreciative and happy customers.
I have 3 new products waiting for me to finish them if only I could get away from this forum for a while.
Regards
Dan Lavry
www.lavryengineering.com
|
|
|
| Re: Proper word clock implementation [message #53552 is a reply to message #53500 ] |
Wed, 23 March 2005 16:44 |
Logichead
Messages: 12
Registered: March 2005 |
Member |
|
|
TOWARDS COMMON SPECIFICATIONS FOR DIGITAL AUDIO INTERFACE JITTER
In the for what it's worth department, google the title above and you will find a white paper on jitter. In section 3.8 it appears to say that jitter is induced by lower bandwidth cable. This would mean high bandwidth cable would be less likely to induce jitter. Isn't that the point of the Apogee digital cable? (BTW, they include measurements.)
So which manufacturer is selling the snake oil? Pot, kettle, black?
More importantly, when these threads become personal they lose their validity. It is with regret and with respect that I make the following request:
Dan - you need to stop using this forum to sell your products and yourself, or resign as moderator. It is inappropriate for you to use your position to attack your competitors and former employers. You (and any other manufacturer) have too much to gain here to be unbiased.
The rest of you - use your friggin' ears to examine what the numbers tell you. There was a time when everyone knew that it was impossible to fly.
Best regards....H
Attachment: towards.pdf
(Size: 159.16KB, Downloaded 133 time(s))
|
|
| | |
| Pages (14): [ 12 ] |
  |
Goto Forum:
Current Time: Fri Dec 5 09:14:07 CST 2008
Total time taken to generate the page: 0.73974 seconds |
Members
Search
FAQ
Register
Login
Home
