|   What is jitter? | bozak
Apr 24, 2001 10:36 AM | | I did a test with three different toslink (optical) cables which
consisted of monster, acoustic research, and rca. The monster was
59$, the acoustic research came free with my hdtv receiver, and
I paid 12.95 for the rca at a store called fry's. I bought the
monster at good guys because a salesman told me it was the cream
of the crop when it came to toslink cables. Being a computer
junky I thought to myself isn't it just one's and zero's being
transfered, but refused on raining on the salesman's parade for
fear of him possibly having some intricate knowledge about
cables that I did not posess.
The salesman told me that if I bought the cheapy cables I would
be subject to a lot of jitter. So I bought one of the monster
cables to see if it truly made a difference.
Needless to say, after I had listened to them all, I could not
tell the difference between the three of them. I did this using
a denon 3801 with a sony 570 dvd player, a sony cd player, and
klipsch speakers. I also did the test using a sony 444es receiver
with a sony dvd and cd player. After doing these tests I can
honestly say that I did not hear the slightest in difference
of sound. That being the case I took the monster back to good
guys, went back to fry's and picked up 5 more of the rca brand
3ft cables at 12.95. I ended up being able to pretty much do
both systems for what it would have cost me for one monster
cable hook up. 380$ vs 65$. I must say the monster cable
looked a lot better than the cheap rca plug, and will probably
last twice as long, but in the long run I would rather go out
and spend 12.95 vs the 59.95 and have cables that aren't as
cute (like it really matters, who is going to see them anyway?).
And finally after using all three, I never heard jitter.
I actually thought jitter was a video term. |
| Jitter is an English word | Norm Strong
Apr 24, 2001 2:27 PM | | It's been around for hundreds of years. The patent has run out on the word jitter so anybody can use it for free--and do! |
| No, you fool........ | Chris Garrett
Apr 24, 2001 9:01 PM | | it's what happens when you're 14, have too much time on your hands (pun intended) and only have the new Sear's Catalog.
Chris |
| A regular Dale Carnegie graduate you ain't.... | Resident Loser
Apr 25, 2001 5:09 AM | | ...."No, you fool" is a phrase best suited for those long meaningful conversations you have with yourself!
Unprovoked, insulting demeanor isn't humorous, but it is revealing.
jimHJJ(...If you have so much on the ball, why not just answer the initial post and dazzle us all with your technical expertise?...) |
| Aw jeez, dude. Lighten up, will ya? | Markw*
Apr 25, 2001 6:23 AM | | I'd lay off the caffiene if I were you. We alls just having some fun today. Let's try to all get along for a change. OK? |
| Was it something that I said.... | Resident Loser
Apr 25, 2001 6:39 AM | | ...BTW, seems you still didn't get that footnote problem straightened out.
jimHJJ(...Oh! I see it's my fault. All the while I tought it was Manuels' fault...I must be punished...BAD Jim...BAD...BAD...BAD...satisfied?...) |
| Jim, it's ALWAYS something you said. | Markw*
Apr 25, 2001 9:27 AM | | Sorry if I offended you bit I just thought your response to Mr. Garret was a little harsh considering that no daggers were thrown.
If it was intended as jest, then I apologize. If not, then I sentence ye to post a pro DBT thread in AA's cable asylum. That outta teach ya.
BTW, you goin' to the show in NY this MAy?
(and, yes, this footnote thing is getting to be a real pain in the asterisk) |
| I felt use of the word "fool".... | Resident Loser
Apr 25, 2001 10:15 AM | | ...in response to Norms' amusing post...inappropriate. That sort of name calling is what has prompted previous exchanges between myself and the imimitable CG. It ain't funny.
Hell, I don't have to post at AA, I've had posts and responses deleted here because I've referred to a couple of the "inmates" in less than glowing terms! Probably couldn't get in the door, even if I wanted to.
Wasn't aware of a show in NY, I'm sorta' out of the loop; visits seem to cascade into purchases...not a good thing...Info please!
jimHJJ(...maybe you should seek the advice of a good accu-punctuationist...all right, all right...I know it was a stretch, don't needle me!...) |
| re: What is jitter? | John T
Apr 24, 2001 10:17 PM | | I thought "JITTER" was something your knees does, when you have the girl friend up against the wall, and you are trying to get it over with before the last bus arrives. |
| re: What is jitter? | DulceBuzz
Apr 25, 2001 8:29 PM | | Get what over? LOL!! |
| Ones and zeros....oh! you poor misguided fellow.... | Resident Loser
Apr 25, 2001 6:28 AM | | ....well that makes at least two of us!
For one school of thought on the subject, check out:
http://www.digido.com/jitteressay.html
Since I am strictly into analog, I can't vouch for its' accuracy, but it sounds reasonable to me. The paragraph immediately following the "waveform" examples pretty much says it all IMHO.
There are others with differing points of view. Claims for cumulative errors, deformed data packets, etc. will be mentioned. I was always under the impression that the built-in safeguards, i.e. buffer circuits, data redundancy and the like, addressed those issues.
There may be some validity, in the attempt to limit errors as best as can be done, due to the fact the error correction circuitry might be overtaxed, which will cause other circuits to be overtaxed or underpowered, etc., etc., etc., and there is a possibility(however slight), that this could have an adverse effect on the resultant sound. To my way of thinking, we're dealing with a non-issue; if the error is that bad you will have no sound!
Finally, unless I'm sadly mistaken, the whole "jitter issue" applies when dealing with separate transports and DACs. A self-contained player is sending an analog signal down the chain, so in that case, the point is moot.
BTW, let me tell you a few things you might be told:
A. You don't know what to listen for.
B. Your experience is anecdotal and therefore irrelevant.
C. The author of the cited url doesn't know what HE'S talking about.
D. I'm an idiot, so don't even pay attention to me.
jimHJJ(...I don't claim to have answers, just a lot of questions...) |
| Ones and zeros....oh! you poor misguided fellow.... | bozak
Apr 25, 2001 9:56 AM | | ....well that makes at least two of us!
For one school of thought on the subject, check out:
http://www.digido.com/jitteressay.html
Since I am strictly into analog, I can't vouch for its' accuracy, but it sounds reasonable to me. The paragraph immediately following the "waveform" examples pretty much says it all IMHO.
Resident Loser
Great article. When I go back to good guys I will ask the salesman
will it also take out the "good jitter" or help prevent "cumlative
jitter". :-) |
| Entire article | Jon Risch
Apr 25, 2001 5:33 PM | | If you read the entire article you reference, then it would become clear that jitter can be a problem during PLAYBACK.
Copying or transfering data without listening to it is not an issue unitl actual data gets corrupted or lost.
However, with a playback event, the DAC must convert the digital signal at the correct and precies moment in time, and if there is jitter in the SYSTEM, it will likely manifest at the DAC during this conversion event.
LIM, bandwidth limitations, and so on, all conspire to cause this.
RL, the mystery to me is, why do you still not understand this part? It has been explained before, in detail with further clarification. Do you just not bother to read these explanations, or what?
I would be interested to know why you still seem to think that real time PLAYBACK is immune from jitter, and why?
Whether or not it is noticed right off is an entire other issue.
Listening comparisons can be difficult to perform, and unless the listener is made aware of what jitter sounds like, it becomes even more difficult to try and discern it initially. It may not be readily apparent on some systems, to some listeners. Overall system performance or overall jitter within certain components may swamp interconnect related jitter.
For more on jitter, and how it can affect PLAYBACK, see:
http://members.nbci.com/Jon_Risch/jitter.html
and
http://www.digido.com/jitteressay.html
AND
http://www.digido.com/wegetletters.html#anchor2484124
http://www.axon.nl/axon/axon_comp.nsf/whitepapers/whitepapers/$file/jitter.pdf
http://www.galstar.com/~ntracy/acg/AandE/npt.on.jitter2.htm
http://www.stereophile.com/fullarchives.cgi?280
(An archived Stereophile review, that shows measured jitter levels.)
http://www.dcsltd.co.uk/papers/jitter.pdf
(Talks about optical based jitter problems toward the end)
http://www.nanophon.com/audio/jitter92.pdf
http://www.nanophon.com/audio/diagnose.pdf
http://www.nanophon.com/audio/towards.pdf
http://www.homecinemachoice.com/frame.html?http://www.homecinemachoice.com/testbench/DVDPlayers/DVDSound.shtml
http://www.benchmarkmedia.com/appnotes-d/jittercu.asp
http://www.music.mcgill.ca/~martin/bibliography/digital/d_conversion.html
http://www.audioprecision.com/publications//audiotst/jan96/jan961.shtml
http://www.audiotest.com/publications/audiotst/dec99/jitter_theory.html
http://www.jitter.de/english/engc_navfr.html
(This site has many links to good references, as well as decent explanations of what jitter is, etc.)
Replication News Article on Jitter:
http://www.AudioAsylum.com/audio/general/messages/977.html
http://www.elantec.com/pages/apppdf/d40954.pdf
(Impedance variations of a short cable)
http://www.toshiba.com/taec/components/Datasheet/TOTX173.pdf
(One of the more popular TOSLINK optical components)
Digital Logic chip output waveforms and ground bounce info:
TI
http://www-s.ti.com/sc/psheets/sdya010/sdya010.pdf
page29-32, waveform views of various devices, shows great shots of non-square square waves
Fairchild
http://www.fairchildsemi.com/ms/MS/MS-541-MISC.pdf
Pages 10-16, digital logic waveforms, showing less than perfect logic signal transmission, ringing, ground bounce, etc. Esp p. 15-16
http://www.fairchildsemi.com/ms/MS/MS-539-MISC.pdf
Shows good waveforms on page 4, also t-line effects for 3 foot cables.
http://www.fairchildsemi.com/an/AN/AN-831.pdf
Shows RF output of logic chips.
http://www.fairchildsemi.com/an/AN/AN-754.pdf
Shows mis-termination results, and (best case) real world waveforms.
http://www.fairchildsemi.com/an/AN/AN-375.pdf
Clearly shows waveform abberations due to the real world.
info on voltage regulator transients, re digital audio and jitter.
http://www.cherrysemiconductor.com/product/PDF/CS-5233-3PDF.pdf page5
http://www.linear-tech.com/pdf/lt0117.pdf, page 5
http://www.national.com/ads-cgi/viewer.pl/ds/LM/LM117.pdf, page 4
http://www-s.ti.com/sc/psheets/slvs297a/slvs297a.pdf
|
| Entire article | Eyespy
Apr 25, 2001 6:20 PM | | You crack me up sometimes. |
| Entire article | Dupper
Apr 25, 2001 8:36 PM | | It's called selective reading and commentary. |
| Wow........That's a lot of info... Your backround and | TinHere
Apr 25, 2001 9:15 PM | | knowlege certainly puts you among the elite IMO. Thanks for sharing. |
| Entire article | mtrycrafts
Apr 25, 2001 11:39 PM | | Oh, Jon, does any of those links cite DBT listening tests to determine what amount of jitter is audible? Didn't think so. A lot of nothing is what you posted, space fillers. Easy to fool some of the people all the time. |
| Entire article | Dupper
Apr 27, 2001 9:38 AM | | your pretty good at asking and answering your own questions. |
| Mother Mary and Joseph..... | Resident Loser
Apr 26, 2001 6:43 AM | | ....I must really tick you off!
Every time my moniker appears connected to a subject you consider sacrosanct, out comes the 2lb hammer and 20d nails when a tack hammer will usually suffice. Overkill to the nth degree. Heaven forbid I include a URL; out comes the bibliography that could choke a horse.
I'm curious, what part of "...I am strictly into analog, I can't vouch for its'( the articles') accuracy..."-"...says it all IMHO..."-"...under the impression..."-"...to my way of thinking..." didn't you understand? Up to that point, the original poster got no real answer, I searched the web and came up with what seemed to be a reasonable reference and provided it along with my opinion(which was so identified). The poster read it and formed his own opinion. Bada-bing,bada-boom.
You could have posted all your info as an answer to the original, but you didn't, you chose to "refute"(if that's the right word) my meager contribution. Gotta' wonder why.
Anyone(read: Dupper) who wishes to cast the shadow of"...selective reading and commentary..." my way, would be better served aiming at those with the "soundbite mentality" and quite possibly themselves.
Any factual info I provide is usually direct from a manufacturers site; other articles are the statements of their respective authors. I provide them for informational purposes only and allow readers to muddle through them for their content of alternate viewpoints. Is there some problem with that?
jimHJJ(...there are two sides to every story...) |
| Entire article | bozak
Apr 26, 2001 1:07 PM | | If you read the entire article you reference, then it would become clear that jitter can be a problem during PLAYBACK.
Copying or transfering data without listening to it is not an issue unitl actual data gets corrupted or lost.
http://www.digido.com/wegetletters.html#anchor2484124
Jon Risch
-------------------
From what I've read in some of the articles you have posted,
especially one of them in that particular url is that imo jitter
comes from the source and not cables. My post was mainly about
how all of the cables no matter what the price sound the same.
This guy Bob in that article mentioned iirc that toslink or
coaxial really wouldnt make a difference as long as you
have a good connection.
I believe that my hearing is good enough to tell if there is
a difference between toslink cables if there was one.
The only difference I believe to exist in the cables are
the materials used and whether or not they are aesthetically
pleasing or not to the eye. Since the cables are behind the
system and not in front, looks do not matter to me. So spending
12.95 vs 59.95 makes a whole lot more sense to me. |
| Entire article | mtrycrafts
Apr 26, 2001 5:36 PM | | >>>. So spending
12.95 vs 59.95 makes a whole lot more sense to me.<<<
A no brainer, right :-) |
| It's what you get when you've had too much caffiene.... | Bruce Burke
Apr 25, 2001 6:32 AM | | Seriously, if you were to look at a square wave signal on an oscilloscope, you'd get a nice steady image. One with jitter would appear to be jumping around somewhat in time making it hard to get a stable lock on the waveform. Sorta like taking a camera and shaking it horizontally at a rapid rate.
Most equipment has the ability, to a point, to be able to reclock the data and filter this stuff out, but it varies depending on the manufacturer.
You can find technical info on Belden's website:
http://www.belden.com/
What would it sound like? I would imagine there are probably several different artifacts that could be created from an echoing(or metalic reverb) effect to a solid low-level whistle, or tone being heard. Probably varies depending on the complexity of the equipment used; again, how well it deals with the problem.
Now, is it a problem in most equipment, well, apparently not in your case. I also doubt that it is in the vast majority of equipment, although there are others who would disagree.
If you have a good scope available to you and can get inside your equipment and find a point right after the optical detector, you'll be able to see if there is any jitter on the signal or not. Don't do this if you're not comfortable with the idea, the stuff is easy to damage by a simple slip of the probe.
-Bruce |
| It's what you get when you've had too much caffiene.... | bozak
Apr 25, 2001 4:21 PM | | If you have a good scope available to you and can get inside your equipment and find a point right after the optical detector, you'll be able to see if there is any jitter on the signal or not. Don't do this if you're not comfortable with the idea, the stuff is easy to damage by a simple slip of the probe.
-Bruce
------------
I'll leave going inside the equipment to people that have a
clue. I don't... :-( |
| re: Good work, bozak... | Monstrous Mike
Apr 27, 2001 10:19 AM | | I like your reply to Jon Risch. Some people are either afraid of a mountain of data, or simply agree with some who provides said mountain. I see you're a person of common sense.
Strictly speaking, jitter is a timing error in a digital signal. Since S/PDIF digital audio is real time audio data, jitter can be a problem. Timing errors can cause output distortions at the DAC. There are many different ways jitter can be introduced into a digital signal, among which cabling is included.
Jitter can be introduced by internal cable reflection due to impedence mismatching which is either an incorrect characteristic cable impedence (S/PIDF calls for 75 ohm cabling) or by connector impedence mismatching.
But the real key to this problem is to realize that most of us have cables in our home which are only 3, 6, or 12 feet long. This is way too short of a cable to cause a reflection in the 3 MHz digital audio signal. I'll bet that you could use an audio cable (as I have done in my own home testing) for your coaxial digital connection and still would not hear a difference.
The bottom line is that I use a decent video cable for my digital coax connection. I've heard of digital coax cables being sold for over $1000! People like to throw around technical terms to encourage the sales of high priced cabling for no audible benefit. It's sad really, and it's the reason lots of people hear recommend common sense in this matter. |
| re: Good work, bozak... | bozak
Apr 29, 2001 12:59 PM | | I like your reply to Jon Risch. Some people are either afraid of a mountain of data, or simply agree with some who provides said mountain. I see you're a person of common sense.
Strictly speaking, jitter is a timing error in a digital signal. Since S/PDIF digital audio is real time audio data, jitter can be a problem. Timing errors can cause output distortions at the DAC. There are many different ways jitter can be introduced into a digital signal, among which cabling is included.
Jitter can be introduced by internal cable reflection due to impedence mismatching which is either an incorrect characteristic cable impedence (S/PIDF calls for 75 ohm cabling) or by connector impedence mismatching.
But the real key to this problem is to realize that most of us have cables in our home which are only 3, 6, or 12 feet long. This is way too short of a cable to cause a reflection in the 3 MHz digital audio signal. I'll bet that you could use an audio cable (as I have done in my own home testing) for your coaxial digital connection and still would not hear a difference.
The bottom line is that I use a decent video cable for my digital coax connection. I've heard of digital coax cables being sold for over $1000! People like to throw around technical terms to encourage the sales of high priced cabling for no audible benefit. It's sad really, and it's the reason lots of people hear recommend common sense in this matter.
Monstrous Mike
----------------------
Thanks. In forums like this I read to learn and mainly, save money.
If buying expensive cables made for a lot better music or ht, I would
be all for it. The testing that I've done on my own tells me that
its not worth it to pay five or ten times the amount of what you
should pay. There are some excellent arguments going on in this
forum that enabled me to get better sound out of the equipment
I have. This forum is a great read. It almost reminds me of
my former stomping ground (the laker newsgroup). I'm glad that
some people take audio so seriously (although maybe some in here
shouldn't). I can deal with the information and misinformation.
I am going to do my own tests anyway. Some of the stuff I've
tried has worked, some of it hasn't. No matter what, I think the
main thing we are all after is better sound. If I can get that
and be entertained a bit, I'm happy.
BTW your description on jitter was the most competent and easiest
to understand after reading most of those articles. Thanks again... |
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