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Great white paper on jitter and clocking
- Thread starter Mivera
- Start date
I call bullshit. After all those words, the author concludes "more research is needed." Nonsense. We already know what levels are below the limits of audibility, and typical amounts of jitter are below those limits. A simple blind test will sort this out. Jitter is a non-issue, and all of these "problems" were manufactured by people hoping to see you newer "better" versions of what you already own.
--Ethan
--Ethan
AJ Soundfield
Major Contributor
CONCLUSION
Because of this apparent lack of consistency between theory and actual experience, more science and measurement is called for, particularly on the perceptual side. Controlled
listening tests involving a cross section of participants using established standards need to be done in order to more fully understand the issue. Marketing materials from many manufacturers use anecdotal evidence and testimony from highly regarded individuals to promote their products and while that is powerful product endorsement, it needs to be recognized as such. Subjective reactions and uncontrolled listening tests, should not be used as a substitute for science and it’s clear that more study needs to be done to fully understand the audible effects of jitter on digital audio.
Yeah I saw that too. Ouch, that's gotta hurt.
Thanks though.
OP
Mivera
Major Contributor
- Thread Starter
- #5
Yes these tests are to prove that the high jitter euphoric distortions aren't really a more accurate representation of the original recording. If you didn't notice the engineers who wrote the white paper are the ones who make the device with the lower jitter specs. If they truly believed higher jitter was beneficial, they would likely use cheaper clocks.
Not sure that follows at all. A subjectivist is just as likely as any objectivist to like euphonic distortions. However the objectivist is more likely to look for other supporting evidence of product performance. The objectivist is more likely to understand and accept that what they hear is subject to these anomalies which may not indicate good product technical performance.
The subjectivist will be more likely to say "I hear it therefore it is" (better).
Last edited:
OP
Mivera
Major Contributor
- Thread Starter
- #7
I'm just basing this on what I've noticed over the last year on forums. I've found that roughly 90% of objectivists have cheap digital gear. So to me this can only mean 1 of 2 things:
1: They subjectively prefer the sound of higher jitter
2: They are too broke or cheap to pay for lower jitter digital gear.
AJ Soundfield
Major Contributor
I did notice. The conclusion contradicts you and all you espouse. That's why I quoted it verbatim.
Now only reading comprehension is required. Ooops.
I think you will need to provide some supporting evidence for that claim
I think you will find its more likely a scenerio that objectivists are less likely to get conned into buying unnecessarily expensive gear that has often very little to offer in improved objective or subjective performance.
AJ Soundfield
Major Contributor
I have found the paper you cited has:
1) Zero listening tests.
2) Zero correlation of price vs jitter vs audibility.
Now go listen to your expensive Nordost cables see what you imagine finding
OP
Mivera
Major Contributor
- Thread Starter
- #12
I think you will need to provide some supporting evidence for that claim
I think you will find its more likely a scenerio that objectivists are less likely to get conned into buying unnecessarily expensive gear that has often very little to offer in improved objective or subjective performance.
Okay just make a poll. Let's have everyone on the forum vote if they consider themselves objectivists or subjectivists. Then after that list the digital gear in their systems. Then we can add up the total costs from both camps and find an average.
AJ Soundfield
Major Contributor
Sure, then have a poll asking so called subjectivists if they own a dictionary with the words subjective and objective.
Umm.. Let's not.
What has cost got to do with performance? One does not necessarily correlate to the other.
Your whole premise is flawed I'm afraid.
AJ Soundfield
Major Contributor
I can hear $$ with my eyes
AJ Soundfield
Major Contributor
You know they taught a horse how to do math once, right? No, not Mr Ed.
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Very pitiful reasoning. It can only mean......... when in fact you attempt to guide discussion and gloss over reality when you say that. Not only does it not ONLY mean, it most likely doesn't mean either of your two false conjectures.
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Okay, how much is enough to be audible, what is the borderline where it becomes inaudible if it is less?
Keith Johnson says 2 picoseconds is audible. I don't believe him.
From here:
http://www.audiophilleo.com/zh_hk/docs/Dunn-AP-tn23.pdf a Julian Dunn paper.
Audibility considerations
It is one thing to be able to identify and measure
sampling jitter. But how can we tell if there is too much?
A recent paper by Eric Benjamin and Benjamin
Gannon describes practical research that found the
lowest jitter level at which the jitter made a noticeable
difference was about 10 ns rms. This was with a high
level test sine tone at 17 kHz. With music, none of the
subjects found jitter below 20 ns rms to be audible.
This author has developed a model for jitter audibility
based on worst case audio single tone signals including
the effects of masking.
This concluded:
“Masking theory suggests that the maximum amount
of jitter that will not produce an audible effect is
dependent on the jitter spectrum. At low frequencies this
level is greater than 100 ns, with a sharp cut-off above
100 Hz to a lower limit of approximately 1 ns (peak) at
500 Hz, falling above this frequency at 6 dB per octave
to approximately 10 ps (peak) at 24 kHz, for systems
where the audio signal is 120 dB above the threshold of
hearing.”
In the view of the more recent research, this may be
considered to be overcautious. However, the
consideration that sampling jitter below 100 Hz will
probably be less audible by a factor of more than 40 dB
when compared with jitter above 500 Hz is useful when
determining the likely relative significance of low- and
high frequency sampling jitter.
Keith Johnson says 2 picoseconds is audible. I don't believe him.
From here:
http://www.audiophilleo.com/zh_hk/docs/Dunn-AP-tn23.pdf a Julian Dunn paper.
Audibility considerations
It is one thing to be able to identify and measure
sampling jitter. But how can we tell if there is too much?
A recent paper by Eric Benjamin and Benjamin
Gannon describes practical research that found the
lowest jitter level at which the jitter made a noticeable
difference was about 10 ns rms. This was with a high
level test sine tone at 17 kHz. With music, none of the
subjects found jitter below 20 ns rms to be audible.
This author has developed a model for jitter audibility
based on worst case audio single tone signals including
the effects of masking.
This concluded:
“Masking theory suggests that the maximum amount
of jitter that will not produce an audible effect is
dependent on the jitter spectrum. At low frequencies this
level is greater than 100 ns, with a sharp cut-off above
100 Hz to a lower limit of approximately 1 ns (peak) at
500 Hz, falling above this frequency at 6 dB per octave
to approximately 10 ps (peak) at 24 kHz, for systems
where the audio signal is 120 dB above the threshold of
hearing.”
In the view of the more recent research, this may be
considered to be overcautious. However, the
consideration that sampling jitter below 100 Hz will
probably be less audible by a factor of more than 40 dB
when compared with jitter above 500 Hz is useful when
determining the likely relative significance of low- and
high frequency sampling jitter.
A little footnote from ESS on the sound of jitter:
Technical Details of the Sabre Audio DAC
Martin Mallinson and Dustin Forman, ESS Technology Technical Staff
http://www.esstech.com/files/4314/4095/4318/sabrewp.pdf -- footnote 15
"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."
Technical Details of the Sabre Audio DAC
Martin Mallinson and Dustin Forman, ESS Technology Technical Staff
http://www.esstech.com/files/4314/4095/4318/sabrewp.pdf -- footnote 15
"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."
