Any sound degradation from using a 3.5mm to dual RCA cable? - AVS Forum
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post #1 of 119 Old 04-18-2014, 04:19 AM - Thread Starter
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I Am looking into finding a sound card but from the looks of it, to use 7.1 surround I'll need to make use of the 3.5mm output ports in order to get it; my receiver has no 3.5mm inputs so I may need to use multiple 3.5mm to RCA adapters. I want to be careful if that's the best idea so I was hoping someone could confirm if by any chance there is any sound degradation from using such an adapter. I've heard some say that when the cable splits the signal for left and right RCA it doesn't really help the audio so much.

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post #2 of 119 Old 04-18-2014, 04:44 AM
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Originally Posted by Tyrone Burton View Post

I Am looking into finding a sound card but from the looks of it, to use 7.1 surround I'll need to make use of the 3.5mm output ports in order to get it; my receiver has no 3.5mm inputs so I may need to use multiple 3.5mm to RCA adapters.

3.5 mm plugs and jacks aren't the most reliable,durable things in the world, but they can be effectively used for handling high quality line level signals. The audio signal put out by most sound cards is unusually robust.
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I want to be careful if that's the best idea

Like a lot of things in this world 3.5 mm jacks aren't the best idea, but they can be reliable and clean-sounding. Their leading problem relates to durability, not signal quality when they are in good mechanical shape.
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so I was hoping someone could confirm if by any chance there is any sound degradation from using such an adapter

If the plug and jack are in good shape, then they are not a bottleneck for sound quality.
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. I've heard some say that when the cable splits the signal for left and right RCA it doesn't really help the audio so much.

People say the darnedest things. In any cable the most unreliable components are typically the connectors, and 3.5 mm suffers from that more than just about any other connector used in the world of audio. One thing that has helped this situation is the wide use of portable digital players.

No manufacturer wants to handle a warranty claim on a $300 portable digital player due to a $0.30 jack, so these parts seem to often be more reliable now than they were in the past.

One helpful tool for easing the load on 3.5 mm jacks is the use of right angle plugs:

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post #3 of 119 Old 04-18-2014, 04:54 AM - Thread Starter
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Thank you very much Arnold, I'll keep an eye out for those right angle connectors.

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post #4 of 119 Old 04-18-2014, 01:29 PM
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Also add that sound cards are in a very noise electrical environment and almost always have low quality D/A converters. The 3.5mm jack may be the least of the quality problems.

You would be better off using an HDMI or S/PDIF port than analog out.
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post #5 of 119 Old 04-18-2014, 01:53 PM
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Originally Posted by William View Post

Also add that sound cards are in a very noise electrical environment and almost always have low quality D/A converters. The 3.5mm jack may be the least of the quality problems.

You would be better off using an HDMI or S/PDIF port than analog out.

Interesting that with all that alleged noise, there are sound cards that have noise as low as even some of the best audio gear.

Reality is that any piece of audio gear with digital circuits inside it has a built-in noise problem, and guess what - even stand alone DACs have digital circuits inside them.

Reality is that there is a area of equipment design called :Mixed signal circuits" that is all about mixing digital and audio circuits in the same box without problems.

Consider a DAC chip - one side of the chip is digital with all the noise that you fear, the other side is analog. They are tiny fractions of an inch apart. No magic, just the art of mixed signal design paying off.

Another example - AVRs. They are now chock full of digital circuits for both audio and video, and the ones with Class D power amps also have switchmode power supplies that would put all but the very largest PC power supplies to shame.

Here are the specs of the analog outputs of an audio interfact that I own:

http://www.lynxstudio.com/pop/product_file.asp?i=22

Frequency Response 20 - 20 kHz, ± 0.05 dB at 44.1 kHz sample rate

Dynamic Range 117 dB, A-wtd.

Signal-to-Noise 117 dB, A-wtd.
Channel Crosstalk <-120 dB,
1 kHz signal @ -1dBFS

THD+N -97 dB (0.0014%) @ -1 dBFS
-104 dB (0.0006%) @ -8 dBFS
1kHz signal, 22Hz - 22kHz BW

It's an ordinary PCI with no special shields, etc:



I've tested it - they tell no lies! ;-)
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post #6 of 119 Old 04-18-2014, 08:14 PM
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Arny, as always, your wisdom and knowledge is beyond us mere mortals. I hope you don't object to me whispering these comments regarding your post smile.gif.
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Originally Posted by arnyk View Post

Interesting that with all that alleged noise, there are sound cards that have noise as low as even some of the best audio gear.
And for every one of those unfortunately, there are tons that don't have low noise. William is right on this note although the fault is not the DAC chip but the implementation.
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Reality is that any piece of audio gear with digital circuits inside it has a built-in noise problem, and guess what - even stand alone DACs have digital circuits inside them.
There is no 2.6 Ghz processor running inside the DAC chip Arny. The bit of logic in a pure DAC is inconsequential in grand scheme of things and at any rate, has been designed by someone who knows what they are doing. Such is not the case usually with the cost and expertise starved PC motherboard and low cost sound card implementations.
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Reality is that there is a area of equipment design called :Mixed signal circuits" that is all about mixing digital and audio circuits in the same box without problems.
Wow Arny. Do you find it that easy to design such circuits? I have managed the development of the same and finding good mixed signal engineers is one of *the* most challenges of any hiring manager. Analog designers don't understand digital and digital designers don't understand analog. This is common knowledge in every engineering circle so I am surprised that your experience is different. Here is a random article that popped up on a search to show that it is not just me talking: http://www.low-powerdesign.com/cadence_karnane.htm. Cadence in case you don't know is one of the top two leaders in engineering design tools (EDA):

"Mixed-signal design environments are not an entirely new ballgame. In the broader context, from an analog perspective, engineers have been doing mixed-signal design for years; however, it seems today that neither analog nor digital engineers are completely prepared to enter each others’ areas of expertise. Analog engineers may shy from the complexity of SoC verification, and digital engineers may find the fuzziness of analog design disconcerting in the context of applications that must run on the chip."


Oh, just realized my good friend who used to write for EDN, Brian Dipert, is on the left side of that article and writes for that site! Small world. I would be curious to know of your experience designing mixed signal circuits or managing people doing the same. I am sure I can get Brian to write an article about that to counter the above if you disagree.
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Consider a DAC chip - one side of the chip is digital with all the noise that you fear, the other side is analog. They are tiny fractions of an inch apart. No magic, just the art of mixed signal design paying off.
Ah, you must be a very good mixed signal designer to find implementing of a DAC in a system that easy. The rest of the engineering world suffers from it and this article nicely states the reasons why: http://www.edn.com/design/analog/4368761/2/Audio-converter-subsystem-design-challenges-in-the-21st-century. And this excellent PDF by Ian Dennis from Prism Sound who I worked with on my article on Jitter in AVRs: http://www.edn.com/Pdf/ViewPdf?contentItemId=4368761

"Advice about the data converter reference voltage
Nearly all data converters have at least one accessible reference voltage (or current) pin. The input
to the converter is multiplied by the reference to produce the output, and so what you do to the
reference is just as important as the analogue signal path: any noise or interference on the reference
will modulate the converter output. Internally-generated voltage references must be filtered with
suitable capacitors placed very close to the pins
– an assortment of low-value HF parts and larger
electrolytic/tantalum types are usually required.

It may be preferable in some situations to drive a voltage reference externally from a well-regulated
and filtered source. Some converter devices require both high and low reference voltages to define
their operating range, and some require separate references per channel. Whilst the actual
reference voltages may sometimes be user-modified to some degree, converter performance is often
optimised at a particular voltage so it's best to stay there.

A parting word: when you have distortion or noise problems, and you've looked everywhere else,
don't forget the reference. If you have modulation issues (sidebands or noise skirts around the signal
frequency): if it gets worse with increasing signal frequency, it's jitter; if it doesn't, it's probably the
reference voltage. Check out [9] if you don't believe me."

Quote:
Another example - AVRs. They are now chock full of digital circuits for both audio and video, and the ones with Class D power amps also have switchmode power supplies that would put all but the very largest PC power supplies to shame.
I have to disagree with you on this one Arny smile.gif. I have written extensively about how poor AVR audio response is when you use HDMI and hence, the video subsystem whales at the same time as audio. Performance is heavily degraded as a result compared to S/PDIF alone. Here is an example in the form of Onkyo AVR:

i-zCFzBVN-L.png

The graph in red is HDMI and the cyan is S/PDIF. Everything other than the main spike in the middle is distortion. Both of these interfaces are "digital" yet the "mixed signal" skills of the designers of this AVR is lacking enough to cause such large degradation in performance when video and the rest of the bits in HDMI are turned on. This is another good example of difficulty of finding people who know what they are doing here and complexity of getting a clean implementation. All the other AVRs I tested suffered the same.
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Here are the specs of the analog outputs of an audio interfact that I own:

http://www.lynxstudio.com/pop/product_file.asp?i=22
Yup. They are "specs" not measurements. My Lynx card cost $1,000. Plug that card into multiple systems and you are liable to get differing performance. Mind you, this is one of the best sound cards out there but it cannot escape the realities of being plugged into different boxes and hence having its performance impacted.

Appreciate any enlightenment you have have time to offer Arny.

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post #7 of 119 Old 04-19-2014, 06:02 AM
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Originally Posted by amirm View Post

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Originally Posted by arny 
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Here are the specs of the analog outputs of an audio interface that I own:

http://www.lynxstudio.com/pop/product_file.asp?i=22

Yup. They are "specs" not measurements.

Ignores something that I wrote that for some strange reason got lost in the quoting which is that I have conformed those specs in my own use of the card. Why do you keep doing that, Amir?
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My Lynx card cost $1,000. Plug that card into multiple systems and you are liable to get differing performance. Mind you, this is one of the best sound cards out there but it cannot escape the realities of being plugged into different boxes and hence having its performance impacted.

Amir after the anecdote with your son's $400 audio interface that performed badly, I understand why you may be skeptical.

I've had that LynxTWO for the better part of a decade (obtained it about the same time the LynxTWO was introduced) and it has resided in countless different PCs. Always meets its specs. What can I say? Somehow I manage to get the best out of the hardware that I have, and often that hardware which I have is near or at best-in-class. It is a curse, I guess!
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post #8 of 119 Old 04-19-2014, 07:40 AM
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That's great Arny. You have had good luck. Do you mind posting a couple of measurements so that we can see what variations there are?

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post #9 of 119 Old 04-19-2014, 07:58 AM
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You two should start a daily Podcast called The Bickering Bickersons Redux. rolleyes.gif
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post #10 of 119 Old 04-19-2014, 08:20 AM
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Quote:
Originally Posted by amirm View Post

That's great Arny. You have had good luck. Do you mind posting a couple of measurements so that we can see what variations there are?

Not a lot in the archives:



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post #11 of 119 Old 04-19-2014, 07:37 PM
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Quote:
Originally Posted by amirm View Post

i-zCFzBVN-L.png

Hmmmm, I do remember being EXTREMELY adamant in saying that just because it's digital it doesn't mean it won't contain any jitter.

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post #12 of 119 Old 04-20-2014, 04:55 AM
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Originally Posted by David Susilo View Post

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Originally Posted by amirm View Post

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Hmmmm, I do remember being EXTREMELY adamant in saying that just because it's digital it doesn't mean it won't contain any jitter.

Well you do seem to have the mastery of the obvious down pat, even if a slight bit of subtlty throws many posts completely off track.

Every sound digital or analog has some jitter in it, most of us but maybe you and Amir are more worried about whether it is actually audible.
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post #13 of 119 Old 04-24-2014, 10:24 AM
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Originally Posted by arnyk View Post

Every sound digital or analog has some jitter in it, most of us but maybe you and Amir are more worried about whether it is actually audible.
Do you have a reference Arny to analog having jitter? Here is the definition from Wiki: http://en.wikipedia.org/wiki/Jitter

"Jitter is the undesired deviation from true periodicity of an assumed periodic signal in electronics and telecommunications, often in relation to a reference clock source."

Analog as you know has no periodicity, nor has a clock. So this definition says there is no such thing as analog "jitter."

Can you please cite any references that describe jitter in the context of analog signals?

As to it not being audible argument, that is what I call the "Bathroom Standard" or BS for short. If I told you that you need to wash your hands after you go to the bathroom, according to this argument you would ask me to prove to you that you will get sick if you didn't. Of course, it is entirely possible that you don't get sick even if you didn't wash your hands five times in a row after going to the bathroom. By that "standard" then we never have to worry about germs when we go to the bathroom. If I showed you under a microscope or UV light that you have picked germs there, you could argue that I have not proven that they can make you sick and therefore that data is not valid. I hope we all agree that such an argument is not valid and that we better wash our hands after using the bathroom.

Based on the BS standard, you could argue that seeing such elevated jitter in HDMI implementation of audio is of no consequence since I have not shown it to be audible to you and I. As with the advice for washing your hands even if you have no proof of getting sick from them, it is prudent to shop for equipment interfaces that do not have such elevated distortions. Sure, you may not hear them. But you can't prove that no one can. If you are into audio as a casual listener aiming to spend as little as you possibly can, sure, such distortions are not a worry for you. But if you are here for days on end wanting to learn about the best audio reproduction, wash your hands, I mean get equipment that doesn't have such distortions smile.gif.

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post #14 of 119 Old 04-24-2014, 08:07 PM
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Originally Posted by arnyk View Post


Every sound digital or analog has some jitter in it, most of us but maybe you and Amir are more worried about whether it is actually audible.

What is "analog jitter" by the way? A new term coined by you? It must be...because you have the mastery of making stuff up down pat! rolleyes.gif

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post #15 of 119 Old 04-25-2014, 04:35 AM
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Originally Posted by David Susilo View Post

Quote:
Originally Posted by arnyk View Post


Every sound digital or analog has some jitter in it, most of us but maybe you and Amir are more worried about whether it is actually audible.

What is "analog jitter" by the way? A new term coined by you? It must be...because you have the mastery of making stuff up down pat! rolleyes.gif

(1) Analog jitter is one of the ugly things that we left behind when mainstream media went digital. The inherent audible jitter in both analog tape and the LP format is huge compared to the vanishing and generally inaudible levels seen in typical digital media. One of the ironies of life is that the high end technocrats go ballistic when they find picoseconds of jitter, but stand mute when their favorite legacy media has thousands of times more.

(2) In music jitter is called "Vibrato". How many musical sounds have vibrato as an inherent component?

BTW the AVS equivalent of XYZZY is to challenge certain people who love to posture hot and heavy about jitter to provide relevant positive listening test results that would meet reasonable standards for controlling bias.
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post #16 of 119 Old 04-25-2014, 05:00 AM
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Originally Posted by amirm View Post

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Originally Posted by arnyk View Post

Every sound digital or analog has some jitter in it, most of us but maybe you and Amir are more worried about whether it is actually audible.
Do you have a reference Arny to analog having jitter? Here is the definition from Wiki: http://en.wikipedia.org/wiki/Jitter

"Jitter is the undesired deviation from true periodicity of an assumed periodic signal in electronics and telecommunications, often in relation to a reference clock source."

Analog as you know has no periodicity, nor has a clock. So this definition says there is no such thing as analog "jitter."

Can you please cite any references that describe jitter in the context of analog signals?

The definition is being quoted correctly but perhaps being applied incorrectly - the scope somehow got narrrowed to just deviations in the clock. In digital systems that is a common cause, but its not the only effect in all of audio.

The assumed periodic signal that is common to both analog and digital systems is the usual frequency components of the source material itself. In analog systems it was called Flutter and Wow which are pretty good descriptions of its audible effects. The jitter in most if not all mainstream analog media is often audible if not very audible.

http://www.aes.org/e-lib/browse.cfm?elib=13

"Measurement of Flutter and Wow in Magnetic-Tape Instrumentation Recorders" Author: The legendary John Mullin

"Specifications for all tape recorders for professional and instrumentation applications include performance figures with regard to flutter and wow. Techniques of measurement give divergent results. The method employed in the author's organization is described, and a comparison is made of results obtained by this method and other methods of less precision."

http://www.aes.org/e-lib/browse.cfm?elib=1498

"Comments on "Perceptibility of Wow and Flutter" By John McKnight - another legend in the realm of analog tape recording.



Another example of analog jitter is FM distortion in loudspeakers:

"Frequency-Modulation Distortion in Loudspeakers," reprinted in the Journal of the Audio Engineering Society, Vol.29 No.5, May 1981.

"Modulation Distortion in Loudspeakers," Journal of the Audio Engineering Society, Vol.17 No.4, April 1969.

"Simulation and Investigation of Doppler Distortion," AES 56th Convention, March 1977.

"The Audibility of Doppler Distortion in Loudspeakers," AES 70th Convention, October 1981.
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post #17 of 119 Old 04-25-2014, 07:29 AM
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Quote:
Originally Posted by arnyk View Post

The definition is being quoted correctly but perhaps being applied incorrectly - the scope somehow got narrrowed to just deviations in the clock. In digital systems that is a common cause, but its not the only effect in all of audio.

The assumed periodic signal that is common to both analog and digital systems is the usual frequency components of the source material itself. In analog systems it was called Flutter and Wow which are pretty good descriptions of its audible effects. The jitter in most if not all mainstream analog media is often audible if not very audible.

http://www.aes.org/e-lib/browse.cfm?elib=13

"Measurement of Flutter and Wow in Magnetic-Tape Instrumentation Recorders" Author: The legendary John Mullin

"Specifications for all tape recorders for professional and instrumentation applications include performance figures with regard to flutter and wow. Techniques of measurement give divergent results. The method employed in the author's organization is described, and a comparison is made of results obtained by this method and other methods of less precision."

http://www.aes.org/e-lib/browse.cfm?elib=1498

"Comments on "Perceptibility of Wow and Flutter" By John McKnight - another legend in the realm of analog tape recording.
Thank you for the answer Arny. I am at a loss as to how this is the answer to the question I asked. I wanted a reference that showed someone else using the term jitter to refer to analog systems as you used it. The references you provided all use the term Wow and Flutter. Let's look at Wiki's definition of Wow and Flutter: http://en.wikipedia.org/wiki/Wow_(recording)

"Wow is a relatively slow form of flutter (pitch variation) which can affect both gramophone records and tape recorders. In the latter, the collective expression wow and flutter is commonly used."

I have highlighted the key word there: "slow." When we speak of jitter in digital systems, often the "speed" variations is measured in billions or even trillionth of second! Nothing about research into audibility of Wow and Flutter has anything to do with such small "speed changes." So to mix the two terms is inappropriate and hence the reason no one else does that. It would be like confusing using wrong size tire with one that is imbalanced on your car. One is a macro problem, the other micro.

As you recall, you and I had this conversation before and I showed in gory detail how Wow and Flutter audibility draws on completely different psychoacoustics. Here is the post on that: http://www.avsforum.com/t/1340051/seeking-education-about-those-ultra-expensive-interconnects/1830#post_20710842. And this summary:
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Originally Posted by amirm View Post

Summary

1. Yes, Flutter and Jitter are forms of FM modulation. For the reasons that it hurts differently if you got hit by a golf ball in the head than a basketball
, just because the roots are the same, it doesn't mean perceptual effects are the same. Flutter amplitude is considerably higher and hence, creates a different situation.

2. Modulation index determines the bandwidth of an FM signal and flutter by definition has a wider distortion spectrum than jitter.

3. While frequency masking is alive and well at all times, its effect can sharply be reduced based on modulation index and with it, allowing distortions to be heard that would not otherwise be as audible.

4. Wow and Flutter standardized curves have a 4 Hz maximum importance with the amount dropping on both sides of that center frequency. Therefore Arny's original thesis is invalidated that as flutter frequencies increase, there is a downward slope in audibility of the distortion. He has acknowledged the same although it doesn't look like anyone picked up on that.

5. As I noted many pages back from the well written and simple presentation by FHG, the explanation of 4 Hz peak appears to be very related to temporal masking where the distance between fluctuations determines audibility.

6. There are cases such as jitter aliasing and data dependent jitter that simply have no analog in flutter. So as much as the levels of jitter can be lower than flutter, it can manifest itself in ways flutter cannot. So one has to be very careful in drawing parallels here. (There are other considerations here that I am not covering here just yet.)

I responded to your objections in this post. This led to your kind admission of your error in this regard:
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Originally Posted by arnyk View Post


Amir, I have already admitted this this was an error in a reply to John Atkinson in post 1768. That hasn't stopped you from bringing it up several times since then. Amir, I guess your new strategy is to avoid responding to valid criticism of your new errors by replaying my old error ad nauseum.

Given the extensive back and forth there and every opportunity to cite the relevant science, I suggest we don't repeat all of that here.

Bottom line is that no one in the industry uses the term jitter to refer to speed variations in analog systems. So its use in these arguments is problematic as it looks like we are trying to spin the truth, pun intended smile.gif. And even if the term were appropriate, drawing analogies between Wow and Flutter and Jitter cannot be done because they are governed by very different psychoacoustics due to their characteristics being so different.

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post #18 of 119 Old 04-25-2014, 07:33 AM
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You reminded me Arny that I wanted to turn the comparison of WoW and Flutter to Jitter into an article. I shall do that soon so that is easier for everyone to read. So I thank you for that too.

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post #19 of 119 Old 04-25-2014, 07:42 AM
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Arny, no musicologist will define "vibrato" as "jitter".
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post #20 of 119 Old 04-25-2014, 07:45 AM
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Lot's of bla bla but still deflecting away from the audibility of digital clock jitter. Jitter is analog to flutter as we knew it the point is with digital it as become inaudible when clock recovery is doing what it should do.
Pico seconds is a folly that crept in after some reviewers and engineers latched onto minute problems highlighted by J test signals .
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post #21 of 119 Old 04-25-2014, 07:46 AM
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And how does jitter creep in through a 3.5mm to stereo RCA cable?
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post #22 of 119 Old 04-25-2014, 09:39 AM
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Quote:
Originally Posted by David Susilo View Post

Arny, no musicologist will define "vibrato" as "jitter".

No one formally educated in control systems theory either. Jitter is a description of a discrete phenomenon where as wow and flutter is not. IMHO, there isn't even room to make an argument that there is even a vague correlation between how these two (three) artifacts affect the reproduced signal.
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post #23 of 119 Old 04-25-2014, 10:07 AM
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Originally Posted by hevi View Post

No one formally educated in control systems theory either. Jitter is a description of a discrete phenomenon where as wow and flutter is not. IMHO, there isn't even room to make an argument that there is even a vague correlation between how these two (three) artifacts affect the reproduced signal.

All three are unwanted variations on clock timing.

How it works out sonically was more clear in the analog era. Wow and flutter are fairly descriptive of the effect. In digital jitter can cover a variety of effects slow clock drift (slow tracking pll) or variations per clock cycle due to noise or internal reference voltages in ic's.
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post #24 of 119 Old 04-25-2014, 11:25 AM
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Originally Posted by Frank Derks View Post

All three are unwanted variations on clock timing.

No, one of the terms is only relevant for discrete signals and the others are only relevant for continuous signals. They are completely different domains and have different nomenclature -with your and army's logic of reasoning a CD would be analogue and an LP is digital.

And this is the problem I have with arnyk's modus operandi; The easy way out, and more importantly, the best way of moving the discussion forward in a constructive way, would have been for arnyk to simply admit that the wording was perhaps a bit off, or similar -it's an honest mistake that we all do from time to time!

But, fact of the matter, arnyk is obviously incapable of doing that -actually admitting he is in fact sometimes wrong, or don't perhaps allways use the correct words or allways build perfect sentences, like the rest of us mortals fail to do on a daily basis!?!

-he'd rather keep on arguing obviously ridiculous arguments indefinitely just to "prove" he is right.

And why do I say this about arny? Is it because I despise him? On the contrary! I actually agree with a fair amount of what he is saying, but I think the good stuff arnyk is actually contributing is getting drowned in his own quest to make sure he himself "is never wrong, even if it is obvious", rather than putting the fact of the matter, the *truth*, in focus. People that are more interested in not beeing wrong than moving this part of the forum forward kind of counteracts the essence of this very part of the forum, and I don't like that...
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post #25 of 119 Old 04-25-2014, 11:46 AM
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Originally Posted by hevi View Post

No, one of the terms is only relevant for discrete signals and the others are only relevant for continuous signals. They are completely different domains and have different nomenclature -with your and army's logic of reasoning a CD would be analogue and an LP is digital.

....

The quantization of the samples amplitude is in the digital domain as is the storage and transport. We all call it digital but actually it really is analog. The Sampling theorem works in the analog domain without digital quantization being necessary.

Wow and flutter originated from capstans and turntable platters not spinning at a constant rate. In a sense this spinning can be considered a clock.
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post #26 of 119 Old 04-25-2014, 12:19 PM
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Originally Posted by Frank Derks View Post

The quantization of the samples amplitude is in the digital domain as is the storage and transport. We all call it digital but actually it really is analog. The Sampling theorem works in the analog domain without digital quantization being necessary.
The samples are discrete in time. It matters not what the amplitude is in this regard. Analog has no discrete samples by definition.
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Wow and flutter originated from capstans and turntable platters not spinning at a constant rate. In a sense this spinning can be considered a clock.
No analog engineer would ever refer to it this way. Hence the reason I asked and Arny could not cite any papers that refer to Wow and Flutter as being jitter or in your case, having a clock. Here is the definition of clock in digital systems: http://en.wikipedia.org/wiki/Clock_signal

"In electronics and especially synchronous digital circuits, a clock signal is a particular type of signal that oscillates between a high and a low state and is utilized like a metronome to coordinate actions of circuits.[...]A clock signal is produced by a clock generator. Although more complex arrangements are used, the most common clock signal is in the form of a square wave with a 50% duty cycle, usually with a fixed, constant frequency. Circuits using the clock signal for synchronization may become active at either the rising edge, falling edge, or, in the case of double data rate, both in the rising and in the falling edges of the clock cycle."


There is no clock that is causing an event to happen at its edges in a turntable. There is a reference speed but achieving that or not, is an analog function, not digital. Hence the use of the word "clock" is totally inappropriate.

Now, if you want to say in layman, non-engineering terms they both sound the same to you, then sure. You can call it photon torpedos for that matter and it would be cool as long as it is not meant to show understanding of the technology....

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post #27 of 119 Old 04-25-2014, 01:39 PM
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Again you fail to grasp the point entirely

Paint a dail on the platter surface and you have a clock.

The motor driving the platter has a set number of poles causing 'pulsing' of the driving force (hey, another 'clock' ) and if that transmits to the platter we get flutter.

Tik tok tik tok.

The only truly analog record players had a crank and rotation was powered by a spring....
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post #28 of 119 Old 04-25-2014, 02:58 PM
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Anybody who have actually heard wow and flutter would never, in their right mind, saying that jitter is analogous to wow and flutter. Jitter is clock related, in analog there is no clock, hence there is no jitter. Plain and simple, no?

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post #29 of 119 Old 04-25-2014, 03:42 PM
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Wow... my hearts a flutter. Gives me the jitters.
Let's get jiggy wit it. Boogie oogie oogie oogie.

Sorry... biggrin.gif
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post #30 of 119 Old 04-25-2014, 04:28 PM
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Quote:
Originally Posted by David Susilo View Post

Anybody who have actually heard wow and flutter would never, in their right mind, saying that jitter is analogous to wow and flutter.

Says you, based on what?

There's a good chance that you've never ever heard jitter from a digital source, as audible jitter is pretty rare in correctly operating digital systems.

OTOH there's a good chance that you've never ever heard audio without jitter from an analog source, as audible jitter is pretty common in even the best analog playback digital systems.
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Jitter is clock related, in analog there is no clock, hence there is no jitter. Plain and simple, no?

Interesting.

I will repeat a pretty good formal definition of jitter from http://en.wikipedia.org/wiki/Jitter

"Jitter is the undesired deviation from true periodicity of an assumed periodic signal in electronics and telecommunications, often in relation to a reference clock source. Jitter may be observed in characteristics such as the frequency of successive pulses, the signal amplitude, or phase of periodic signals."

Notice that it says "often in relation to a reference clock source" but not "always in relation to a reference clock source".

Analog playback has a presumed time base just as surely as digital playback. In analog the presumed time base is related to the motion of the media that has the sound engraved on it (Vinyl) or embedded in it as magnetic variations (magnetic tape). Since the velocity of these media with respect to the stylus or playback head is prone to small variations, there is an variation in the time base of the signal just as surely as if it were sampled.

In reality all of these things are FM distortion.

FM distortion in speakers is a little more complex to visualize, but it is again just another example of FM distortion.

I can intentionally create digital jitter, analog flutter or FM distortion with the same modulating frequency and modulation index or degree of modulation and it will all sound pretty much the same.

There is even audio editing software that was originally designed for doing things like pitch correction that was found to be capable of identifying and correcting jitter in analog recordings:

http://www.celemony.com/en/start

http://www.celemony.com/en/capstan

"
For over a hundred years, music has been recorded on mechanical mediums. And for over a hundred years, there has been a problem with this: wow and flutter. Who isn’t familiar with the wobbling and warbling, the droning and dragging? Mechanical degradation caused by defective devices or sticking tapes, by ageing or defective storage. In the past, it was usually impossible to get rid of wow and flutter.

Countless recordings of renowned orchestras, big bands and rock groups are currently slumbering deep in archives. Yet they are unusable, simply due to wow and flutter. The tapes worthless, the recordings lost to posterity. Until now.

For, in Capstan, there is now for the first time a program capable of removing wow and flutter from recorded music. Whether on tape, compact cassette, wax, shellac or vinyl.
"

Wow, flutter, FM distortion, Jitter, even vibrato - they are all different names for the identical same basic physical process - time distortion.
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