What does jitter ACTUALLY sound like? (jitter test tracks)

[tuga]

The following website has some simulated jitter test tracks:

What does jitter ACTUALLY sound like?​

There are seven versions of each sample. Three have periodic jitter, three have random jitter, and one is the original - untouched. In the samples we have 2µs (microseconds), 4µs, 8µs, 16µs RMS jitter. It is unlikely in the real world for a digital-to-analog converter to have a jitter higher than 2µs RMS. I threw in the 4µs, 8µs, and 16µs samples to see what some extreme cases sound like. As you scroll down you can listen to them and make your best guess of which is which. Then you can click the sample's title (i.e. 1kHz v1) to see if your guesses are right.
Before you move on, here is something to keep in mind. The clock interval of a 44.1 kHz signal is 22.7 µs, meaning, there is a sample every 22.7 µs. Jitter is expressed in RMS microseconds. So when we say there is a 2µs RMS jitter, it means the clock was, on average, off by 2µs.

what does jitter ACTUALLY sound like?

In a previous post we had an encounter with jitter in audio. The talk about jitter is hard to miss these days. There are plenty of products on the mar...

www.sereneaudio.com

 

[Music707]

For the sake of completeness: Another reference was pointed out by @Blumlein 88 in the following thread:

Archimago's jitter files

https://archimago.blogspot.com/2018/08/demo-musings-lets-listen-to-some-jitter.html Saw this being discussed over at CA. Thought there is some interest here more than likely. Archimago has posted some synthetically created jitter at various levels on some pieces of music and a sweep tone...

www.audiosciencereview.com

Link to the source:

DEMO / MUSINGS: Let's listen to some jitter simulations with sideband distortions...

A blog for audiophiles about more objective topics. Measurements of audio gear. Reasonable, realistic, no snakeoil assessment of sound, and equipment.

archimago.blogspot.com

 

[DonR]

Considering most modern DACs, even very cheap ones, have jitter in the 100s of picoseconds or less, it does make one think.

 

[fpitas]

Considering most modern DACs, even very cheap ones, have jitter in the 100s of picoseconds or less, it does make one think.

Thinking that some audiophiles are out of their minds, you mean?

 

[MRC01]

As I understand it, jitter, wow and flutter are essentially the same thing: frequency/pitch variations. But jitter happens on a microscopic scale where wow & flutter are more of a macroscopic scale. So it manifests differently in terms of audibility. Wow & flutter at audible levels sound like pitch variations (for example the dreaded warbling note fade-out on analog piano recordings) but jitter at audible levels sounds more like spurious tones, like IMD or HD.

 

[OldHvyMec]

Max Headroom is close.

 

[kemmler3D]

It's shockingly less noticeable on the music... but the correlated jitter does legitimately sound horrible. Glad to know almost nothing has that much jitter anymore.

 

[pkane]

The following website has some simulated jitter test tracks:

What does jitter ACTUALLY sound like?​

There are seven versions of each sample. Three have periodic jitter, three have random jitter, and one is the original - untouched. In the samples we have 2µs (microseconds), 4µs, 8µs, 16µs RMS jitter. It is unlikely in the real world for a digital-to-analog converter to have a jitter higher than 2µs RMS. I threw in the 4µs, 8µs, and 16µs samples to see what some extreme cases sound like. As you scroll down you can listen to them and make your best guess of which is which. Then you can click the sample's title (i.e. 1kHz v1) to see if your guesses are right.
Before you move on, here is something to keep in mind. The clock interval of a 44.1 kHz signal is 22.7 µs, meaning, there is a sample every 22.7 µs. Jitter is expressed in RMS microseconds. So when we say there is a 2µs RMS jitter, it means the clock was, on average, off by 2µs.

what does jitter ACTUALLY sound like?

In a previous post we had an encounter with jitter in audio. The talk about jitter is hard to miss these days. There are plenty of products on the mar...

www.sereneaudio.com

There's another way to listen to jitter, using your own music track(s) and with more control over the type and amount of jitter: use my DISTORT app to apply jitter. You can play the file, or save it to listen to it in an ABX tester, if you want. You can mix random noise modulated jitter with correlated and close-in noise, as well as any number of individual frequency components in any proportion.

https://distortaudio.org

Dial in different types of jitter and listen:

 

[mhardy6647]

Max Headroom is close.

Beat me to it.

 

[Blumlein 88]

The weird thing is maybe more than any aspect of digital audio is the hand wringing over jitter. Yet with maybe one exception, it simply has never since the very first CD player been large enough to be of any consequence whatsoever. The other exceptions are some of these HDMI boxes that split out the audio which often have very high jitter. But we are talking about $30 or less devices. Also wow and flutter is a similar issue with tape and LP which is orders of magnitude larger than what is on digital audio sources. Even more so, since most things digital have moved on to USB connection DACs run off a local free running clock which has exceptionally low levels of jitter in the great majority of cases.

 

[tuga]

If I remember correctly jitter became an issue when the CD player was split into two boxes, back in the late '80s or early '90s.

Anyway, @RayDunzl posted a description from an old ESS white paper of how jitter sounds in another topic:

"The noise that jitter induces is not easily described: it is not a harmonic distortion
but is a noise near the tone of the music that varies with the music: it is a noise that
surrounds each frequency present in the audio signal and is proportional to it.
Jitter noise is therefore subtle and will not be heard in the silence between audio
programs. Experienced listeners will perceive it as a lack of clarity in the sound
field or as a faint noise that accompanies the otherwise well defined quieter
elements of the audio program."

As with any other type of distortion its audibility is probably both system, programme and listener dependent.

 

[Blumlein 88]

If I remember correctly jitter became an issue when the CD player was split into two boxes, back in the late '80s or early '90s.

Anyway, @RayDunzl posted a description from an old ESS white paper of how jitter sounds in another topic:

"The noise that jitter induces is not easily described: it is not a harmonic distortion
but is a noise near the tone of the music that varies with the music: it is a noise that
surrounds each frequency present in the audio signal and is proportional to it.
Jitter noise is therefore subtle and will not be heard in the silence between audio
programs. Experienced listeners will perceive it as a lack of clarity in the sound
field or as a faint noise that accompanies the otherwise well defined quieter
elements of the audio program."

As with any other type of distortion its audibility is probably both system, programme and listener dependent.

Nope.

It was then pushed as a possible problem that needed a solution with 2 boxes. In fact with 2 boxes it all remained low enough to be a non issue. It is something you don't need to worry about.

Very nearly all the "issues " with digital audio are attempting to create demands and differentiation for things that have never been broken in the first place.

 

[tuga]

Nope.

It was then pushed as a possible problem that needed a solution with 2 boxes. In fact with 2 boxes it all remained low enough to be a non issue. It is something you don't need to worry about.

Very nearly all the "issues " with digital audio are attempting to create demands and differentiation for things that have never been broken in the first place.

Low enough... Is that your opinion?

@John_Siau seems to acknoledge that it is an issue (albeit, from his point of view, a solved one in his own DACs).

The Unique Evils of Digital Audio and How to Defeat Them

The Unique Evils of Digital Audio And How to Defeat Them By John SIau August 2010 We are all too familiar with the criticisms of digital audio. We have heard digital audio described as harsh, brittle, lifeless, tense, cold, and non‐musical. Perhaps each of us can add our own adjectives to this...

benchmarkmedia.com

 

[Blumlein 88]

Low enough... Is that your opinion?

@John_Siau seems to acknoledge that it is an issue (albeit, from his point of view, a solved one).

The Unique Evils of Digital Audio and How to Defeat Them

The Unique Evils of Digital Audio And How to Defeat Them By John SIau August 2010 We are all too familiar with the criticisms of digital audio. We have heard digital audio described as harsh, brittle, lifeless, tense, cold, and non‐musical. Perhaps each of us can add our own adjectives to this...

benchmarkmedia.com

Not only solved, but never really a problem. John Siau comes close to spreading FUD here. 20 picoseconds is the level required to cause a change in the lowest bit from effects of jitter (and that only at the highest frequencies). However that does not mean it is audible. The available info indicates audibility is much higher. Besides noise in real recordings is high enough jitter has to be much higher to come out of that noise floor. Not the noise floor of the digital format, but the noise floor of recordings.

So no, while jitter could be a problem it effectively never has been. And it darn sure is not today in anything other than the lowest quality, incompetent designs like sub $30 HDMI to analog converters. Maybe that is a good test, to offer the original file and the heavily jittered file from such a converter.

I also have a device that has huge levels of jitter for a few seconds. I could provide that assuming it still works (I've not fired it up for a few years and it is 20 years old).

Jitter is not causing one device to sound sub-standard or less resolving vs other devices.

 

[tuga]

Not only solved, but never really a problem. John Siau comes close to spreading FUD here. 20 picoseconds is the level required to cause a change in the lowest bit from effects of jitter (and that only at the highest frequencies). However that does not mean it is audible. The available info indicates audibility is much higher. Besides noise in real recordings is high enough jitter has to be much higher to come out of that noise floor. Not the noise floor of the digital format, but the noise floor of recordings.

So no, while jitter could be a problem it effectively never has been. And it darn sure is not today in anything other than the lowest quality, incompetent designs like sub $30 HDMI to analog converters. Maybe that is a good test, to offer the original file and the heavily jittered file from such a converter.

I also have a device that has huge levels of jitter for a few seconds. I could provide that assuming it still works (I've not fired it up for a few years and it is 20 years old).

Jitter is not causing one device to sound sub-standard or less resolving vs other devices.

You are assuming that jitter does not modulate the noise floor of the recording/music programme/signal. Is that correct (paper)?

 

[Blumlein 88]

You are assuming that jitter does not modulate the noise floor of the recording/music programme/signal. Is that correct (paper)?

No, I am not assuming that. I am saying that jitter doesn't do enough of that to be audible until levels are much higher than has been typical of DACs.

Is jitter audible?

I have been reading some comments online where several audio experts have suggested that jitter is not audible. Is this actually correct?

www.audiosciencereview.com

How many DACs have jitter in the few nanosecond range?

https://mentor.ieee.org/802.11/dcn/04/11-04-1458-00-000n-jitter-requirements.ppt

 

[Blumlein 88]

Think of it this way. With 24 bit audio, any distortion above -144 db will alter the lowest bits. This is like the idea jitter above 20 picoseconds can alter 16 bit audio. Yet does this mean any distortion above -144 db is audible? No it does not. One will preclude the possibility of jitter or thd being audible. While the other aspect is much more than that is required to be audible even if it is measurably different.

 

[pma]

Think of it this way. With 24 bit audio, any distortion above -144 db will alter the lowest bits.

And it does not need to be distortion, it may be truncating or rounding - purely math operations. People often go ad absurdum in their reasoning.

 

[fpitas]

Maybe audiophiles just get the jitters?

 

[OldHvyMec]

Maybe audiophiles just get the jitters?

There is a point of analyzing that makes my head heart. I use to get the shakes before a punch out, does that count?
I've never had an issue with jitter. Seldom do I use a DAC and the units I use have never displayed the Max Headroom
issues. I use to experience a CD anomaly in units equipped with CD many years ago. It was related to a track change,
minor vibration and any sudden jarring of the unit. I seldom see any of that in newer production and CDs for the most
part, have to ordered special. Memory HDs and streaming are king in the NEW world. Jitter is a term, but for all practical
purposes one that I've never experienced.

It use to crack me up to hear a CD trying to recover, then spit it out on the floor.
Kinda like loosing it's lunch or my uncle spitting out his false teeth.