[pinnahertz]

Yes, wow on turntable is technically FM, but because the modulating frequency is so low, the side bands it creates are too close to the
"carrier" to create a modulating noise product. Wow is, of course, directly audible. The bigger concern is that tape scrape flutter is recorded on vinyl.

 

[watchnerd]

 
Obsess all you like about digital jitter, it's already inaudible, but we've had the analog version for decades. 

 
From the listening tests I've done:
 
1. For non-randomized sine waves in the upper midrange 2k-4khz, I've been able to identify jitter vs not as low as -60 dBFS on ABX tests.  That's still far higher than most decent products.
 
2. For non-randomized sine waves in the low bass, <60 Hz, it was shockingly high, something like -30 dBFS
 
3. When the same jitter from #2 was combined with music that had heavy bass content (i.e. masking), things got worse, in the range of -15 dBFS to -20 dBFS
 
4. For jitter with music, I can most easily ABX it on solo piano and solo cymbals, but only at levels that are much higher than one might think
 
5. With complex orchestral music, I failed the ABX test within the parameters being tested, i.e. the test didn't go high enough.

 

[pinnahertz]

How did you generate the jitter(ed) samples?

 

[watchnerd]

How did you generate the jitter(ed) samples?

 
In this example, I didn't.  That was part of a test at Dolby Labs. I was a test subject.  I don't know what they used to generate the files.
 
However, there are also several online jitter tests, as well.  Hydrogen audio has some, Crane also.

 

[nick_charles]

   
In this example, I didn't.  That was part of a test at Dolby Labs. I was a test subject.  I don't know what they used to generate the files.
 
However, there are also several online jitter tests, as well.  Hydrogen audio has some, Crane also.

 
Were you one of Benjamin and Gannon's subjects - cool !

 

[watchnerd]

   
Were you one of Benjamin and Gannon's subjects - cool !

 
I signed an NDA, so can neither confirm nor deny. The results haven't been published..not sure if they will be or it will be kept internal.
 
It was at the SF office.

 

[nick_charles]

   
I signed an NDA, so can neither confirm nor deny. The results haven't been published..not sure if they will be or it will be kept internal.
 
It was at the SF office.

 
The study I was referring to is from 1998
 
Theoretical and Audible Effects of Jitter on Digital Audio Quality
Eric Benjamin and Benjamin Gannon
Dolby Laboratories Inc.
San Francisco, CA 94103-4813, USA
 
Published by the AES ...It was at the time the best attempt to define Jitter audibility , your experience however sounds similar to the tests they did in 98' , one hopes the study you participated in will be published ...fwiw their most successful subject detected 20ns of 1700Hz jitter in music (a 5 second sample from McGill University) but their threshold test was self-administered so not as rigorous as it could have been! That said they chose the most intrusive config they could and the musical samples it was most likely to audibly mangle - they concluded
 
"The influence of jitter in causing audible distortion was found to be less than anticipated by the authors, and less than that predicted by both the technical and consumer audio press. Jitter induced by the digital audio interface was not found to be an audible problem for any of the program material auditioned."
 

 

[watchnerd]

   
The study I was referring to is from 1998
 
Theoretical and Audible Effects of Jitter on Digital Audio Quality
Eric Benjamin and Benjamin Gannon
Dolby Laboratories Inc.
San Francisco, CA 94103-4813, USA
 
Published by the AES ...It was at the time the best attempt to define Jitter audibility , your experience however sounds similar to the tests they did in 98' , one hopes the study you participated in will be published ...fwiw their most successful subject detected 20ns of 1700Hz jitter in music (a 5 second sample from McGill University) but their threshold test was self-administered so not as rigorous as it could have been! That said they chose the most intrusive config they could and the musical samples it was most likely to audibly mangle - they concluded
 
"The influence of jitter in causing audible distortion was found to be less than anticipated by the authors, and less than that predicted by both the technical and consumer audio press. Jitter induced by the digital audio interface was not found to be an audible problem for any of the program material auditioned."
 

 
Ahh..no, the study I participated in was done in 2015.
 
In only did the 2 channel part.  There was another group where they were testing them in multi-channel settings.

 

[GuyUnder]

Jitter is consciously perceptible at fairly high levels. Any modern DAC, even little baby Chinese DACs, have a clock that are good enough to reduce jitter to levels that are not perceptible as jitter. So the battle isn't with old-school, extremely obvious jitter.
 
Instead of just explaining how jitter at low levels matters, let's see what respected industry manufacturers have to say:
 
MSB (builders of what many consider to be the finest DACs in the world):
 
"Our years of experience taught us amplitude (DAC) precision contributes to the realism of the instruments and voices while low clock jitter decreases ‘digital harshness’ and increases focus. Jitter simply takes the pleasure out of the music and creates listener fatigue."
 
Antelope Audio (famous in high end pro audio):
 
"Leading producers, sound engineers, artists, and movie post production studios worldwide are using the 10M Atomic Clock together with our high-end Trinity master clock. They usually describe it as “mind-blowing”, an “instantaneous improvement”, “superior”, and fundamental in bringing “more detail, ambiance, and naturalness” to the digital signal. The results are described as “wider and more solid” with “crisp transients and a 3D depth of field.”
 
---
 
Low-level jitter does have an impact on audio perception. This is well-known not only by manufacturers, but by DIY'ers as well.
 
A comparison with inter-module distortion is handy. It's known that IMD isn't generally audible in modern equipment -- because the brain filters out IMD artifacts, but IMD is seen as negative because it is theorized to lead to listener fatigue (it's a theory because it involves neuroscience but it's still a widely accepted view). You won't hear jitter, or noise in general below a certain threshold -- but that doesn't mean that it doesn't effect you.
 
I am certain beyond any shadow of a doubt -- if readers of this thread were to plug their headphones of choice (well, headphones that aren't trash anyway) into my reference system, the difference between it and their DAPs, little integrated units, etc, were would very obvious. A lot of that difference will come down to the effort and expense gone into reducing jitter and noise in the system.

 

[spruce music]

  Jitter is consciously perceptible at fairly high levels. Any modern DAC, even little baby Chinese DACs, have a clock that are good enough to reduce jitter to levels that are not perceptible as jitter. So the battle isn't with old-school, extremely obvious jitter.
 
Instead of just explaining how jitter at low levels matters, let's see what respected industry manufacturers have to say:
 
MSB (builders of what many consider to be the finest DACs in the world):
 
"Our years of experience taught us amplitude (DAC) precision contributes to the realism of the instruments and voices while low clock jitter decreases ‘digital harshness’ and increases focus. Jitter simply takes the pleasure out of the music and creates listener fatigue."
 
Antelope Audio (famous in high end pro audio):
 
"Leading producers, sound engineers, artists, and movie post production studios worldwide are using the 10M Atomic Clock together with our high-end Trinity master clock. They usually describe it as “mind-blowing”, an “instantaneous improvement”, “superior”, and fundamental in bringing “more detail, ambiance, and naturalness” to the digital signal. The results are described as “wider and more solid” with “crisp transients and a 3D depth of field.”
 
---
 
Low-level jitter does have an impact on audio perception. This is well-known not only by manufacturers, but by DIY'ers as well.
 
A comparison with inter-module distortion is handy. It's known that IMD isn't generally audible in modern equipment -- because the brain filters out IMD artifacts, but IMD is seen as negative because it is theorized to lead to listener fatigue (it's a theory because it involves neuroscience but it's still a widely accepted view). You won't hear jitter, or noise in general below a certain threshold -- but that doesn't mean that it doesn't effect you.
 
I am certain beyond any shadow of a doubt -- if readers of this thread were to plug their headphones of choice (well, headphones that aren't trash anyway) into my reference system, the difference between it and their DAPs, little integrated units, etc, were would very obvious. A lot of that difference will come down to the effort and expense gone into reducing jitter and noise in the system.

We know how sure you are.  That confidence doesn't indicate that you are correct in that opinion.
 
You should read the link I posted earlier about external clocks.  Despite the comments about atomic clocks and such it is a measurable certainty that an external clock regardless of how high the quality of that clock is introduces low level jitter above a self clocked device.  What you read in the testimonial is someone being influenced by all the hoopla around such things.  This causes them to hear what they expected to hear.
 
The comments about IMD are non-sensical.  IMD is not harmonically linked to fundamentals, therefore not masked by them as well and more obvious when heard.  Yet when levels are low enough you cannot hear IMD, guess what......you can't hear it.  It can't effect your hearing because you can't hear it. Usually anything below -70 db IMD will do the trick.  Now we could supply you with files with various levels of noise or jitter or IMD and let you find at what level you no longer hear them.  It wouldn't do a lick of good.  You will just insist based upon nebulous subjective feelings about listening to gear that some unheard or unmeasured distortion is certain to be the cause. 
 
To ask an oft asked question, under what conditions or what kind of test would you accept that you are incorrect about this jitter business?  What would it take to convince you that you can't hear low level jitter of a few hundred picoseconds?  That there are no subliminal effects of low level jitter ?

 

[watchnerd]

 
So the battle isn't with old-school, extremely obvious jitter.
 

 
Please define "old-school jitter" and how it differs from the usual definition of jitter.
 
This is not an engineering term, so I have no idea what you mean by it.

 

[nick_charles]

  Low-level jitter does have an impact on audio perception. This is well-known not only by manufacturers, but by DIY'ers as well.
 
I've never seen that assertion rigorously tested anywhere. I'm sure it is possible to find lots of anecdotes but I'd prefer to see some stronger evidence if you have it.

 

[sonitus mirus]

I've never seen that assertion rigorously tested anywhere. I'm sure it is possible to find lots of anecdotes but I'd prefer to see some stronger evidence if you have it.

 
Thanks for your input.  I understand that one of the responsibilities in your profession is to be a scholarly peer reviewer; and, to me, you are one of the most valued contributors to this forum.  Now you, I, and practically everyone else that frequently participates in this forum is probably confident that your comment and pedigree won't make a lick of difference to the person you replied to, but I sincerely hope that it may influence others that stumble across this thread in the future.

 

[pinnahertz]

  Jitter is consciously perceptible at fairly high levels. Any modern DAC, even little baby Chinese DACs, have a clock that are good enough to reduce jitter to levels that are not perceptible as jitter. So the battle isn't with old-school, extremely obvious jitter.
 
Instead of just explaining how jitter at low levels matters, let's see what respected industry manufacturers have to say:
 
MSB (builders of what many consider to be the finest DACs in the world):
 
"Our years of experience taught us amplitude (DAC) precision contributes to the realism of the instruments and voices while low clock jitter decreases ‘digital harshness’ and increases focus. Jitter simply takes the pleasure out of the music and creates listener fatigue."

The above is about as ambiguous as it gets. No figures, no thresholds. Like jitter is an on/off kind of function. The above proves nothing but the ability to write ad copy.

 
Antelope Audio (famous in high end pro audio):
 
"Leading producers, sound engineers, artists, and movie post production studios worldwide are using the 10M Atomic Clock together with our high-end Trinity master clock. They usually describe it as “mind-blowing”, an “instantaneous improvement”, “superior”, and fundamental in bringing “more detail, ambiance, and naturalness” to the digital signal. The results are described as “wider and more solid” with “crisp transients and a 3D depth of field.”

This one's even worse. "Leading producers, sound engineers....." Who? "Top men." Yeah, right. No specifics, you got nothin'. And so how they "usually describe" anything is an equally worthless statement. If none of them felt strongly enough for a personal endorsement, who cares? Again, ad copy only. Not even good.  
---
 

Low-level jitter does have an impact on audio perception. This is well-known not only by manufacturers, but by DIY'ers as well.

Odd there are no references....

 
A comparison with inter-module distortion is handy.

IMD=Inter-Modulation Distortion.

It's known that IMD isn't generally audible in modern equipment -- because the brain filters out IMD artifacts, but IMD is seen as negative because it is theorized to lead to listener fatigue (it's a theory because it involves neuroscience but it's still a widely accepted view).

It depends on what specific modern equipment you're talking about. There's a whole class of very expensive, very professional gear that can be (and often is) adjusted in such a way as to result in huge amounts of unintentional, but very audible IMD. Wanna hear some? Listen to FM radio a while.
 
The brain DOES NOT filter out IMD artifacts...complete hogwash.
 
IMD Does increase listener fatigue, and you don't need neuroscience to show that. Audio processing research has that done...and has had for decades.
 

You won't hear jitter, or noise in general below a certain threshold -- but that doesn't mean that it doesn't effect you.

What,specifically, is that effect that affects us, if we can't hear it?  

 
I am certain beyond any shadow of a doubt -- if readers of this thread were to plug their headphones of choice (well, headphones that aren't trash anyway) into my reference system, the difference between it and their DAPs, little integrated units, etc, were would very obvious. A lot of that difference will come down to the effort and expense gone into reducing jitter and noise in the system.

 

Want to do a DBT/ABX on that hypothesis? Yeah, didn't think so.



 

 

[pinnahertz]

   
Please define "old-school jitter" and how it differs from the usual definition of jitter.
 

Jitter occurring within the confines of a structure built before 1950 for the purpose of education.