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Topic: Is jitter audible and what does it sound like? (Read 46807 times) previous topic - next topic
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Is jitter audible and what does it sound like?

I hope I put this in the right forum. You've probably been asked this a million times, but I trawled the web (mostly searching "dan lavry" + "jitter", as I figured he was the "master") as well as his forum, and I couldn't really find my answer, so I asked on his forum (which gave this response: http://www.lavryengineering.com/lavry_foru...f=1&t=7449), and I'll also ask here to hear your opinion:

If we're talking home audio listening (not recording), is jitter then audible, and how does it sound? I'm only talking about playing CDs and digital audio files from either a CD player, or your computer or a streamer through a dac into your amplifier.
Let's also for the time being assume that the analogue to digital conversion during recording/mastering was done well to begin with, and let's assume that the converter you use is of fairly good quality.

I discussed this with an audiophile friend. My own impression is that with 16 bit audio, jitter starts to become audible at -96 dB (without dithering), so with music recorded at sensible levels, it will not be audible, as all jitter is in the noise floor, and the music would mask the jitter. An exception could of course be orchestral music with a huge dynamic range recorded at a very low volume (so the noise floor would be raised). As for how jitter sounds, the video "Digital show & tell" on Xiph.org says quantization noise sounds like tape hiss from analogue tapes, but I might be mixing up quantization noise with jitter (is it the same?). On that website, there's also a file available for download with a 1 kHz tone at -105 dB. When playing that file there's background noise, which I assumed was jitter. In other words, jitter is present in all digital audio, but the amount is so low that you can never hear it except for in those extreme cases mentioned above. I asked Ethan Winer who said:
"Jitter manifests as noise 100+ dB below the music, and is never audible. Nor does it create 'a lack of depth, solidity and a smearing of the stereo image.' You’re thinking of wow and flutter. :->)"

In Ethan Winer's Youtube video "AES Damn lies workshop", he shows the following picture:



My friend's attitude is that jitter is omnipresent and always audible and smears the stereo image etc. (like the comment above), so although he exclusively listens to digital audio he is starting to think vinyl might be the way to go to get rid of the issue of jitter. Surface noise, pops, clicks, etc. from vinyl can be filtered out by our brains, whereas jitter is an omnipresent 'grating' and unpleasant sound.

I of course understand that when creating converters like Dan Lavry does, it's important to minimise jitter as much as possible in order to come closer to creating the perfect product, as well as creating an A/D converter that will have minimal jitter so the recording artists can raise and lower levels on different tracks as much as they like. But as mentioned, I'm only interested in audibility and listening at home – not in the technical aspect (measuring, etc.).
"What is asserted without evidence can be dismissed without evidence"
- Christopher Hitchens
"It is always more difficult to fight against faith than against knowledge"
- Sam Harris

Is jitter audible and what does it sound like?

Reply #1
Jitter doesn't have anything to do with stereo.  Its basically just instability of the sampling clock, which causes sidebands around pure tones.  Usually its not audible though, since you need to have quite a lot of it before you'll even get the signal above the noise floor of modern music. 

It tends to be a much bigger problem in things like RF, since the frequencies are much higher.

Is jitter audible and what does it sound like?

Reply #2
My friend's attitude is that jitter is omnipresent and always audible and smears the stereo image etc. (like the comment above), so although he exclusively listens to digital audio he is starting to think vinyl might be the way to go to get rid of the issue of jitter. Surface noise, pops, clicks, etc. from vinyl can be filtered out by our brains, whereas jitter is an omnipresent 'grating' and unpleasant sound.


Your friendly is sadly very misinformed. Jitter in digital audio does manifest itself as noise in the signal. But like you said, it's way below audible levels, unless the recording is done at a ridiculously low level. It can't do anything else, and certainly not "smear" anything at all. To claim that it is omnipresent and "grating" just shows that your friend has bought into the audiophile bullshit machine, big-time.

If your friend is so worried about jitter, he should be absolutely mortified at the amount of wow on vinyl records, even good ones. There can be a significant pitch difference as the record spins if the center hole isn't perfectly aligned. You mostly notice it on long sustained tones like organ music, you get a warbling or pitch rising and faling with the ~1.8 second period of the record's rotation.

Wow on a vinyl record is several orders of magnitudes beyond even very bad digital jitter, and the noise floor is significantly higher.

And that's before you get into other effects such as pre-echo (you can hear a faint copy of loud transients ~1.8 seconds before they hit, because the grooves slightly distort each other during the vinyl production process, or because the master tape has suffered from bleed-through. And of course, everything gets worse the closer you get to the center of the record, as there is less vinyl in each groove per revolution, so the dynamic range and noise floor suffers.

Is jitter audible and what does it sound like?

Reply #3
My friend's attitude is that jitter is omnipresent and always audible and smears the stereo image etc. (like the comment above), so although he exclusively listens to digital audio he is starting to think vinyl might be the way to go to get rid of the issue of jitter. Surface noise, pops, clicks, etc. from vinyl can be filtered out by our brains


I think your friend thinks that vinyl is better because he can hear Surface noise, pops, clicks, etc, then he immediately knows it is vinyl and sound quality is automatically improved in his brain.

Is jitter audible and what does it sound like?

Reply #4
When playing that file there's background noise, which I assumed was jitter.

Not a good assumption in any experiment with 20 nuisance variables. Better account for/eliminate them all before ascribing any cause>effect.

Surface noise, pops, clicks, etc. from vinyl can be filtered out by our brains.

Audiophile brains, yes. Music lover no. I attend too much live classical and acoustic music to filter those completely alien artifacts. My references for sound isn't Foghat or other audiophiles stereos.

whereas jitter is an omnipresent 'grating' and unpleasant sound.

That is better remedied by a psychiatrist than a turntable.

cheers,

AJ
Loudspeaker manufacturer

Is jitter audible and what does it sound like?

Reply #5
If we're talking home audio listening (not recording), is jitter then audible, and how does it sound?


Jitter is FM distortion which has two properties:

(1) The frequency of the modulation, measured in Hz of the modulation frequency.  For example due to the 33 1/3 rotation speed of LPs, it is very common of them to have large amounts of jitter at 0.5555 Hz.  For another example, due to some geometric effects, it is also very common to also have large amounts of jitter at the fundamental resonant frequency of the tone arm which is usually ab out 10 Hz.

(2) The amount of the modulation which is given in in the deviation in HZ or amount of frequency change due to the jitter.

Jitter was a far greater and more intractable problem with analog recording such as the LP and analog tape. It is also a problem with FM radio reception that is affected by multipath.

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I'm only talking about playing CDs and digital audio files from either a CD player, or your computer or a streamer through a dac into your amplifier.


In general this jitter involves modulation frequencies and deviations that are inaudible.

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Let's also for the time being assume that the analogue to digital conversion during recording/mastering was done well to begin with, and let's assume that the converter you use is of fairly good quality.


Then there is no audible jitter.

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I discussed this with an audiophile friend. My own impression is that with 16 bit audio, jitter starts to become audible at -96 dB (without dithering), so with music recorded at sensible levels, it will not be audible, as all jitter is in the noise floor, and the music would mask the jitter.


That's not true because the jitter is not fully defined.  The audibility of jitter is dependent on both the frequency of the modulation which in your example is unspecified, and its deviation which could be discerned  mathematical means if the modulation frequency were known.


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An exception could of course be orchestral music with a huge dynamic range recorded at a very low volume (so the noise floor would be raised).


That's false because jitter is usually independent of dynamic range.  An audio signal can be jittered a certain amount regardless of its level, whether loud or soft.


Quote
As for how jitter sounds, the video "Digital show & tell" on Xiph.org says quantization noise sounds like tape hiss from analogue tapes, but I might be mixing up quantization noise with jitter (is it the same?).


Yes, quantization noise and jitter are two very different things and should not be confused with each other.

If you want to hear jitter, the easiest way may be to listen to a LP record or analog tape, particularly a cassette tape. Almost any playback of them will include audible jitter.


Is jitter audible and what does it sound like?

Reply #7
Your friend might be more inclined to notice "grating" flaws in recordings (and there are many) when he's listening to the digital version, because analog = more better.  The irony is of course that the best analog can't match the noise floor of mediocre digital recording.  Another explanation could be dynamic range compression and deliberate clipping, which wasn't really possible until digital manipulation advanced sufficiently.  This could certainly be described as an "omnipresent grating sound," though it is in no way the fault of digital to analog conversion.  Without having any idea what he's listening to or comparing, it's hard to say if his complaint is purely perceptual bias, or just a confusion of correlation and causation.

Edit: I wouldn't be quick to completely dismiss your friends' perception.  Is analog a better medium for sound reproduction?  Absolutely not.  Could a digital "remaster" be made to sound much worse than the original?  Of course.

Is jitter audible and what does it sound like?

Reply #8
The noise floor of digital recordings is something draws me to digital devices that definitely have a good noise floor themselves more often than not.  I've had my moments where I preferred an analog version over the digital version (usually if the digital version is a bad remaster) but it's rare and even rarer a noisier version of something (old school game consoles that didn't have the greatest of sound systems, usually).  Not going to lie there.

Is jitter audible and what does it sound like?

Reply #9
My own impression is that with 16 bit audio, jitter starts to become audible at -96 dB (without dithering), so with music recorded at sensible levels, it will not be audible, as all jitter is in the noise floor, and the music would mask the jitter.

I'm curious to learn how you arrived at this impression. Is it due to the diagram in Ethan's video? If so, you would read it wrongly. The diagram has nothing to do with audibility. It tries to answer the question what magnitude the jitter artifacts have in what situation. Whether they are audible is an entirely different question which depends on many more factors, amongst them are masking properties of human hearing.

The diagram you found in Ethan's video essentially derives from work done by the late Julian Dunn, who is sometimes quoted by audiophiles in quite misleading ways. You read the diagram like this: If your audio signal is a pure sine wave of the frequency shown on the horizontal axis, then a jitter signal which is also a sine wave will create modulation products of the level shown on the vertical axis, when its magnitude is as written on the diagonal lines. Note that both audio and jitter signals are assumed to be sinusoidal. That's not the case an audiophile is usually interested in. It is the case where jitter effects are most readily noticeable. If the jitter signal is noise, which is the usual case, the effect is orders of magnitude less audible. This has been confirmed by listening tests. Similarly, when the audio signal is music, the effect is also much less audible. The highest sensitivity of human hearing for jitter effects arises, when both jitter and audio signals are sine waves, and the frequency of the audio and jitter signals is chosen such that the modulation products fall into the most sensitive region of hearing, and are outside the masking region. In other words, you can handcraft a scenario that maximizes the chance of hearing it. If you do that, some people can detect jitter in the lower single figure ns range. With ordinary music, you are in the double figure ns. If the jitter signal is noise, you need a jitter magnitude of well beyond 100 ns to have a chance of hearing it.

It is fairly easy to build digital gear with jitter figures of a nanosecond or below, so unless someone has goofed, pretty much any gear should be good enough, jitter-wise. Therefore, it is a non-problem. If you find gear that exceeds a few ns of jitter, consider it defective or misdesigned. Both of those may happen, of course. Competition for ever-lower jitter figures well below a nanosecond may be technically challenging, but is sonically irrelevant.

Note also that jitter is measured and expressed in a variety of different ways which may render two figures uncomparable. Hence to be sure you would have to know more about the measurement conditions than most people are likely to tell you. In audiophile circles, hardly anyone seems to have enough clue of even the basics to deliver a meaningful measurement, so the figures which are claimed for various pieces of gear are likely bunk. Sometimes people buy an oscillator off-the-shelf and use the manufacturer data, without checking if it still holds true on their board, which is far from self-evident, and usually overoptimistic.

And then people confuse interface jitter with sampling jitter, which again leads to complete nonsense.

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As for how jitter sounds, the video "Digital show & tell" on Xiph.org says quantization noise sounds like tape hiss from analogue tapes, but I might be mixing up quantization noise with jitter (is it the same?).

No it isn't the same. It has entirely different root causes. Quantization noise would be there regardless of whether there is jitter or not. Quantization noise is amplitude noise, whereas jitter is time-domain noise. Jitter modulates the audio signal, whereas quantization noise simply adds to the signal. The effects of both can be similar if the jitter signal indeed takes the form of random noise, which it may or may not, depending on its origin.

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On that website, there's also a file available for download with a 1 kHz tone at -105 dB. When playing that file there's background noise, which I assumed was jitter.

No, it is quantization noise. In fact, it is dither, which is a way of making quantization noise purely random, so that it sound like continuous noise. Without dither, quantization noise may be correlated to the audio signal, which means that the noise coloration changes with the audio signal. The file is supposed to demonstrate that the noise floor is not a limit for audibility. It is possible to hear signals which are below the noise floor. This has to do with the fact that noise is a broadband effect across a whole range of frequencies, whereas the sine wave is a narrow band thing with a narrowly defined frequency. That can be exploited by both the ear and by measurement instruments.

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In other words, jitter is present in all digital audio, but the amount is so low that you can never hear it except for in those extreme cases mentioned above.

That's a fair characterization for the vast majority of cases.

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My friend's attitude is that jitter is omnipresent and always audible and smears the stereo image etc. (like the comment above)

He almost certainly never checked how much jitter was present in his own trials. And he never checked how much jitter would have to be added in order to make its effects audible. His opinion is pure belief, instilled by "interested parties".

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I of course understand that when creating converters like Dan Lavry does, it's important to minimise jitter as much as possible in order to come closer to creating the perfect product, as well as creating an A/D converter that will have minimal jitter so the recording artists can raise and lower levels on different tracks as much as they like. But as mentioned, I'm only interested in audibility and listening at home – not in the technical aspect (measuring, etc.).

Minimizing jitter can be an interesting technical challenge, which can be pursued independently from any audibility considerations. If audibility is the key factor, it is enough to follow ordinary design practices, and check the result with your favorite audio analyzer.


Is jitter audible and what does it sound like?

Reply #11
Thanks for all your responses, everybody, and thanks for the jitter soundclips, Arnie. You answered my question of "how does jitter sound?" 

I better state something about my friend before anybody else makes any more comments about him. I thought I made it clear in my original post, but apparently not:
To the best of my knowledge he has never owned a turntable. He's not a vinyl freak. He's been asking me about what gear to buy and what particular vinyl records I could recommend (I was "vinyl only" for 15 years, and have now done a lot of A/B'ing with vinyl and CD as well as various turntables). He's a hi-fi manufacturer, and he's considering buying a turntable purely for his showroom, as many potential clients could come in and ask for a demonstration with a turntable (you know, analogue is always better - we all know that). At one point he said he wouldn't want to switch to vinyl as it was too troublesome (cleaning, the price, etc.).
As for what types of music he listens to, then it's varied, but mostly "nice" modern recordings (Diana Krall and the like) and classical music. Although he might listen to a few compressed albums (like Daft Punk) here and there, it doesn't seem common for him.
And yes, I think he might have been influenced by the audiophile community who's nowadays constantly talking about jitter. 20 years ago it was never an issue, whereas nowadays it's apparently on everybody's lips as the new thing that everybody has to fix. I mean, I'm also asking this question here because I've been reading those sort of articles/comments.

Did anybody read the response I got on Dan Lavry's forum? The link is in my original post. I know that he's somewhat in the "other" camp (audiophile camp), although he seems very, very scientifically minded. Yet, the response from one of his employees seems to be the complete opposite of all your responses: Jitter is always present, and will give a grating sound, unless it's drastically reduced (and still it will always be somewhat audible). I'm still a novice in this field, so I can't concur or contradict anything. I am, of course, aware that Lavry's company is selling a product, and if they state that jitter is an issue, and they then can sell us a product that solves this problem, then it's money in their pockets. That said, I do have a lot of respect for them, and they seems to be some of the most straightforward, no-bullshit manufacturers out there .

And yes, I probably understand Ethan Winer's picture like you explained it, Pelmazo. Also I understood the short entry about Jitter here http://wiki.hydrogenaud.io/index.php?title...Vinyl%29#Jitter as saying jitter was just in the noise floor.

So, anyway, if I understand you all correctly, then jitter will be audible in a recording where the analogue to digital conversion was poorly done, or it will be present in a well-converted recording (A/D) if the digital to analogue conversion (by the DAC in the CD player) is being poorly done. The latter is not so likely nowadays (if it ever really was). The first one might have been a problem in the 80s, or it can still be a problem if poorly designed A/D converters are used. And there might also be other things in the chain that could have gone wrong, so it can be a bit random if jitter is audible or not.
"What is asserted without evidence can be dismissed without evidence"
- Christopher Hitchens
"It is always more difficult to fight against faith than against knowledge"
- Sam Harris

Is jitter audible and what does it sound like?

Reply #12
Did anybody read the response I got on Dan Lavry's forum? The link is in my original post.


I got like 10 lines in.  Does that count? 

I'm still a novice in this field, so I can't concur or contradict anything. I am, of course, aware that Lavry's company is selling a product, and if they state that jitter is an issue, and they then can sell us a product that solves this problem, then it's money in their pockets. That said, I do have a lot of respect for them, and they seems to be some of the most straightforward, no-bullshit manufacturers out there .


Salesmen must love you.

Is jitter audible and what does it sound like?

Reply #13
Did anybody read the response I got on Dan Lavry's forum? The link is in my original post. I know that he's somewhat in the "other" camp (audiophile camp), although he seems very, very scientifically minded. Yet, the response from one of his employees seems to be the complete opposite of all your responses: Jitter is always present, and will give a grating sound, unless it's drastically reduced (and still it will always be somewhat audible). I'm still a novice in this field, so I can't concur or contradict anything. I am, of course, aware that Lavry's company is selling a product, and if they state that jitter is an issue, and they then can sell us a product that solves this problem, then it's money in their pockets. That said, I do have a lot of respect for them, and they seems to be some of the most straightforward, no-bullshit manufacturers out there .

Much of the factual information he offers is correct, but you must have noticed that for all the subjective opinions and experiences he gives, he doesn't even attempt to provide any quantitative estimates, or verifications. That's the usual state of affairs for the last decades: People who are convinced of the importance of jitter and of its audibility, have no hard evidence on offer for it. One would wish that particularly those who can give a more or less accurate technical account of what jitter is, would go the extra mile and verify their perceptions with a well designed experiment. You can contemplate why this doesn't happen.

Let me add a few corrections to Brad Johnson.

Strictly speaking, jitter does not count as quantization error. The process of converting analog signals to digital involves two processes: Sampling and quantization. They both occur in the A/D converter, and often even at the same point in the circuit, but it is useful to keep them separate on a conceptual level. Sampling is a time-domain thing, because it involves taking snapshots of the signal at regularly spaced points in time. This can be done in a purely analog fashion with no digital circuitry involved. Quantization is an amplitude-domain thing, as it separates a continuum of analog voltage levels into a fixed number of "bins", with each bin carrying a number. The CD for example, with its 16-bit format, has 65536 bins. Quantization introduces errors, because a range of voltages falls into a single bin, so once quantized they can't be distinguished any more. Note that the error needn't be noise in the common sense. For example, if you have a very low level signal whose amplitude is so small that it falls into a single bin, the resulting digital code is always the same number, which means silence. It takes dither to randomize the error, so that it becomes noise. With dither, the situation is exactly as it would be in analog, where there is always a noise floor, even when there is no signal. Noise floor and signal are effectively independent. Furthermore, if you provide more bins (i.e. more bits in the number), the range for each bin gets smaller, and so the average error gets smaller. The result is a reduction in the level of the noise. One more bit doubles the number of bins, halves the amplitude range that is represented by each bin, and reduces the average error by half. The noise level reduction is approximately 6 dB.

Since Jitter is a time-domain thing, it needs an audio signal to produce an effect. If a voltage is constant over time, it doesn't matter how accurately you hit the right points in time when sampling. The resulting numbers would be the same. The error resulting from sampling at the wrong point in time will be largest when the signal goes through a steep slope, i.e. varies rapidly. This happens at high frequencies at high level. Therefore, the best test signal for measuring the effects of jitter is a high pitched sine wave near the upper end of the frequency scale at full volume. That's another reason for being sceptical about the audibility of jitter, since music does not typically contain high frequencies at full volume. (This is, by the way, the reason for the sloped lines in Ethan's diagram.)

Brad Johnson probably knows this, and I don't think he wanted to misrepresent anything. It is a sloppy way of talking about these things that lumps the errors into a common concept. I just happen to believe that it doesn't help understanding, so I prefer to stick to the clearly defined terms.

I also prefer to emphasize the distinction between sampling jitter and interface jitter. Brad Johnson did make this distinction in spirit, but it wasn't very obvious. It is important to clarify this. Sampling jitter is what we are concerned with when we talk about errors at the point of conversion from analog to digital or vice versa. The relevant clock signal for this is the clock that drives the sampler in the A/D converter. This clock is very rarely accessible from the outside of a box. It may be accessible on a circuit board, and if you are equipped with enough knowledge and tools you may be able to measure its jitter directly. In practice, it is much easier to measure the jitter effect in the resulting audio, because that can be done outside of the box.

Interface jitter happens at a digital interface, such as S/P-DIF. Since the signal at this point doesn't directly drive a converter, its effect on the sampling quality is unknown. It may not have any effect at all. Measuring the interface jitter therefore doesn't allow any conclusion about the audio quality. Interface jitter is usually measured with an oscilloscope displaying a so-called eye diagram. The purpose of such measurements is to assess the likelihood of bit errors, i.e. the probability that you get errors in the data recovery at the receiving end. If there are such data recovery errors, the wrong data likely leads to clicks in the audio, which will be fairly apparent and bears no resemblance to the kind of impairment commonly associated with jitter.

There are cases where the sampling clock is derived from the incoming digital signal. In such cases, interface jitter may result in sampling jitter. Whether this happens, and to what extent it happens, depends on the details of the circuit involved. Gear does vary in this respect. This is what Brad described as "jitter immunity". This term describes the relationship between interface jitter and sampling jitter, i.e. how much of the former results in how much of the latter. Jitter immunity matters if your situation involves both of the following:
  • You have a significant amount of interface jitter
  • The receiver of the digital signal derives the sampling clock from it.

Brad noted a situation when the second point doesn't apply: The source device is synchronized to the receiver, i.e. there is a second connection feeding a synchronization signal from the receiver to the signal source. In this case the receiver can generate the sampling clock locally, and interface jitter has no effect on sampling jitter.

Is jitter audible and what does it sound like?

Reply #14
So, anyway, if I understand you all correctly, then jitter will be audible..

No, you don't understand correctly. There is zero evidence that jitter is, or ever had been audible in Hi-Fi equipment. Ever. There is evidence to the contrary.
If you, your friend or Lavry et al could present evidence to the contrary, by all means do so. But it's been more than 30 years. Still waiting for these witch effects to show up at dawn during trust your ears only evaluations.
"Omnipresent jitter" is one of the many symptoms of audiophile disorder (a subset of Digital disorder).

I was "vinyl only" for 15 years, and have now done a lot of A/B'ing with vinyl and CD as well as various turntables

How many of those A/Bs were done with vinyl vs a level matched 16/44 rip of that vinyl?

cheers,

AJ

Loudspeaker manufacturer

Is jitter audible and what does it sound like?

Reply #15
How many of those A/Bs were done with vinyl vs a level matched 16/44 rip of that vinyl?


I do have a question about ABXing vinyl and vinyl rip. A vinyl rip can have very consistent performance during playback because it is already digitized, but can a turntable have enough consistency in each playback? For example, if we rip a vinyl two times and ABX the two rips, can they sound different? Are there any research about this?

Is jitter audible and what does it sound like?

Reply #16
So, anyway, if I understand you all correctly, then jitter will be audible..

No, you don't understand correctly. There is zero evidence that jitter is, or ever had been audible in Hi-Fi equipment. Ever. There is evidence to the contrary.
If you, your friend or Lavry et al could present evidence to the contrary, by all means do so. But it's been more than 30 years. Still waiting for these witch effects to show up at dawn during trust your ears only evaluations.
"Omnipresent jitter" is one of the many symptoms of audiophile disorder (a subset of Digital disorder).

I was "vinyl only" for 15 years, and have now done a lot of A/B'ing with vinyl and CD as well as various turntables

How many of those A/Bs were done with vinyl vs a level matched 16/44 rip of that vinyl?

cheers,

AJ


Ha, they both sound like crap.

Is jitter audible and what does it sound like?

Reply #17
can a turntable have enough consistency in each playback?

It is conceivable that the position of a click may give enough of a hint for identifying the source that is playing. The limitations of vinyl players certainly limit ABX test protocols. You just can't repeat a signal as easily as you can loop a piece of a sound file.

Is jitter audible and what does it sound like?

Reply #18
I love the way people casually throw around "A/B"

analogue is always better - we all know that

I hope you're only joking.

Is jitter audible and what does it sound like?

Reply #19
I do have a question about ABXing vinyl and vinyl rip. A vinyl rip can have very consistent performance during playback because it is already digitized, but can a turntable have enough consistency in each playback? For example, if we rip a vinyl two times and ABX the two rips, can they sound different? Are there any research about this?

Don't know, but the rip will capture all that lovely vinyl + TT blah, blah sound. I have my doubts that one subsequent replay would be discernible (i wouldn't try it with 100), but if not, it puts those with the disorder at an advantage, in that there would be something to differentiate. So now all we need is one positive "A/B".
It should be good therapy either way, however temporary.

cheers,

AJ
Loudspeaker manufacturer

Is jitter audible and what does it sound like?

Reply #20
I do have a question about ABXing vinyl and vinyl rip. A vinyl rip can have very consistent performance during playback because it is already digitized, but can a turntable have enough consistency in each playback? For example, if we rip a vinyl two times and ABX the two rips, can they sound different? Are there any research about this?


The most obvious problem here would be static noise and pops, since it is not consistent between playbacks, and could be used to identify the 'live' vinyl record with enough repeated tests.

Is jitter audible and what does it sound like?

Reply #21
As I've mentioned here in other threads, the proper way to ABX test direct, live vinyl to a digitized version of it is via a nearly instantaneous (low latency) A>DA>A loop, the exact same methodology used by Meyer and Moran to compare the live, analog out of an SACD player to a digitized version it via a standalone CD recorder put in "record monitor" mode. Pops, ticks, and clicks won't give away which source is being played because you are hearing the exact same playback session of the vinyl either way.


Is jitter audible and what does it sound like?

Reply #23
Great method, thanks mzil, and thanks for the aes link as well. Audiophiles should spend a bit to read the paper rather than spending a lot to "fix" a nonexistent problem.

Is jitter audible and what does it sound like?

Reply #24
Did anybody read the response I got on Dan Lavry's forum? The link is in my original post. I know that he's somewhat in the "other" camp (audiophile camp), although he seems very, very scientifically minded.


To the poorly informed, a good charlatan will sound very, very scientific.  It doesn't matter which part of science we're talking about, this is how pseudoscience is done for fun and  profit.

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Yet, the response from one of his employees seems to be the complete opposite of all your responses: Jitter is always present, and will give a grating sound, unless it's drastically reduced (and still it will always be somewhat audible).


That's the usual line of pseudoscientific bull - a mixture of true and false claims.

True statement: Jitter (and every other form of noise and distortion) is always present. (because nothing in the real world is perfect).

False claim: Jitter will give a grating sound  unless it's drastically reduced (and still it will always be somewhat audible).

True correction to the above false claim: Jitter can easily be low enough that it has no audible effect.

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I'm still a novice in this field, so I can't concur or contradict anything. I am, of course, aware that Lavry's company is selling a product, and if they state that jitter is an issue, and they then can sell us a product that solves this problem, then it's money in their pockets.


Hold those thoughts.

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That said, I do have a lot of respect for them, and they seems to be some of the most straightforward, no-bullshit manufacturers out there .


Not at all.

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And yes, I probably understand Ethan Winer's picture like you explained it, Pelmazo. Also I understood the short entry about Jitter here http://wiki.hydrogenaud.io/index.php?title...Vinyl%29#Jitter as saying jitter was just in the noise floor.


That's the nature of noises and distortion that are too low to be audible by anybody - they are lost in the noise.  In the real world there is always a noise floor.

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So, anyway, if I understand you all correctly, then jitter will be audible in a recording where the analogue to digital conversion was poorly done, or it will be present in a well-converted recording (A/D) if the digital to analogue conversion (by the DAC in the CD player) is being poorly done. The latter is not so likely nowadays (if it ever really was). The first one might have been a problem in the 80s, or it can still be a problem if poorly designed A/D converters are used. And there might also be other things in the chain that could have gone wrong, so it can be a bit random if jitter is audible or not.


All recordings that are, will be, or ever were made on analog media (analog tape and LP) are very likely to have audible jitter because one of the reasons that analog media was generally scrapped is because its jitter and other forms of audible noise and distortion could never be reduced below audibility.

If a recording is made digitally, thus avoiding analog media, using audio gear with average or better quality, then it is likely to be free of audible jitter and every other kind of audible flaw. This is easy enough to demonstrate by means of a straight wire bypass test where a back-to-back analog and digital converter is compared to a short piece of wire. It is easy enough to do this by comparing a recording to itself after being re-recorded digitally.

By not directing people to do straight wire bypass tests under bias-controlled conditions, the myth that digital converters and all other kinds of audio gear are not quite good enough is perpetuated for fun and profit.