Head-Fi.org › Forums › Equipment Forums › Dedicated Source Components › An interesting paper on jitter audibility
New Posts  All Forums:Forum Nav:

An interesting paper on jitter audibility - Page 2

post #16 of 112
12/18/06 at 9:01am
Quote:
Originally Posted by audioengr View Post
I for one, I am "wasting my time" on jitter because:
Note I said if
Reply
post #17 of 112
12/18/06 at 11:24am
Thread Starter 
Quote:
Originally Posted by audioengr View Post
Even better, play a variety of music with the reference system using a source with known larger jitter, say 250 psec and then change to a source with know lower jitter, say 50 psec. I would predict that most trained listeners would hear the difference.
As long as the sources were unknown and the order randomised so that subjects and test administrator are unaware of source identity this would work to see if subjects could detect a difference between sources.

However this does not mean that you are isolating jitter as the only variable you have to prove first (de minimus) that the FRs are totally identical and all other audio characteristics, SNR, dynamic range, THD, electrical noise, transport noise, all factors except jitter are utterly identical (or as near as damn it) or suitably controlled.

This is why the study cited is interesting as for each subject there is one independent variable, jitter. Granted a standard procedure would be better, however their results do seem to indicate a high level of generalizability across subjects and settings.
Reply
post #18 of 112
12/19/06 at 6:03pm
I strongly agree with audioengr that these audio professionals tend to have tin ears and cannot be trusted, and this is from personal experience. A select group of audiophiles is much more dependable because it is their passion, and often they also have musical training and know how real instruments are supposed to sound like. what subjects you pick makes a world of difference in these tests. these "audio professionals" also said that all amps sound the same, and I wouldn't be surprised if one day they claimed that all speakers sound the same, all headphones sound the same, etc.
Reply
post #19 of 112
12/19/06 at 6:31pm
Quote:
Originally Posted by cotdt View Post
I strongly agree with audioengr that these audio professionals tend to have tin ears and cannot be trusted, and this is from personal experience. A select group of audiophiles is much more dependable because it is their passion, and often they also have musical training and know how real instruments are supposed to sound like. what subjects you pick makes a world of difference in these tests. these "audio professionals" also said that all amps sound the same, and I wouldn't be surprised if one day they claimed that all speakers sound the same, all headphones sound the same, etc.
To do an sloppy job because it becomes boring doesn't mean that they are not trained, who is going to hire someone that has no clue of what they are doing, I don't know what kind of professionals you have met in your life, but all what I have meet, also are musicians in most cases, and have really good ears, as logic indicates....please stop putting all professionals in the same bag, that is not true at all, audiophiles may be a best selection for those tests, but professional can't be put aside like that, maybe just becasue the results are not of your liking...
Reply
post #20 of 112
12/19/06 at 7:17pm
Thread Starter 
Quote:
Originally Posted by cotdt View Post
I strongly agree with audioengr that these audio professionals tend to have tin ears and cannot be trusted, and this is from personal experience. A select group of audiophiles is much more dependable because it is their passion, and often they also have musical training and know how real instruments are supposed to sound like. what subjects you pick makes a world of difference in these tests. these "audio professionals" also said that all amps sound the same, and I wouldn't be surprised if one day they claimed that all speakers sound the same, all headphones sound the same, etc.

You are missing the point. This debate is not about how good or bad kit sounds but about whether jitter in CD systems is audible, i.e whether jitter is actually a problem or not. While different listeners may have different criteria for good or bad is not in debate, however here the issue is really simple - what levels of jitter can anybody reliably detect, i.e how much jitter does there have to be before can anybody detect the difference between a signal with jitter and that signal without jitter.

I find the suggestion that AEs have such bad hearing or are so incompetent that they would do this very simple task less well than anybody else utterly absurd and I daresay if I were an AE pretty insulting. Try floating this idea on ProSoundWeb and see what folks there think about it.

Please point me to any properly controlled blind test where "Audiophiles" could reliably detect the presence or absence of jitter that AEs could not.

Incidentally some of the listeners in the paper under debate were musicians and none of them could detect jitter at less than 500ns.
Reply
post #21 of 112
12/19/06 at 7:20pm
Quote:
Originally Posted by cotdt View Post
I strongly agree with audioengr that these audio professionals tend to have tin ears and cannot be trusted, and this is from personal experience.
What is the nature of your personal experience?

Quote:
A select group of audiophiles is much more dependable because it is their passion,
I, for one, would love to see a group of audiophiles participate in a properly designed double-blind experiment regarding audibility of jitter.
Reply
post #22 of 112
12/19/06 at 7:21pm
As I quoted in my previous post, there were musicians in the group as well.
Reply
post #23 of 112
12/19/06 at 7:22pm
Quote:
Originally Posted by hciman77 View Post
You are missing the point. This debate is not about how good or bad kit sounds but about whether jitter in CD systems is audible, i.e whether jitter is actually a problem or not. While different listeners may have different criteria for good or bad is not in debate, however here the issue is really simple - what levels of jitter can anybody reliably detect, i.e how much jitter does there have to be before can anybody detect the difference between a signal with jitter and that signal without jitter.

I find the suggestion that AEs have such bad hearing or are so incompetent that they would do this very simple task less well than anybody else utterly absurd and I daresay if I were an AE pretty insulting. Try floating this idea on ProSoundWeb and see what folks there think about it.

Please point me to any properly controlled blind test where "Audiophiles" could reliably detect the presence or absence of jitter that AEs could not.

I have posted some things on prosound bulletin boards. This is where I got to be so jaded about them. I found that most of them only care about measurements, not even what is audible...

Steve N.
Reply
post #24 of 112
12/19/06 at 7:24pm
Quote:
Originally Posted by Febs View Post
What is the nature of your personal experience?



I, for one, would love to see a group of audiophiles participate in a properly designed double-blind experiment regarding audibility of jitter.
I do single-blind tests at CES, but I find the differences are anything but subtle. Even sighted tests work...

Steve N.
Reply
post #25 of 112
12/19/06 at 7:30pm
Quote:
Originally Posted by Febs View Post
I, for one, would love to see a group of audiophiles participate in a properly designed double-blind experiment regarding audibility of jitter.
I would love to see the objectivist crowd actually listen to the equipment first rather than take measurements and assume that all is known.
Reply
post #26 of 112
12/19/06 at 7:31pm
Quote:
Originally Posted by audioengr View Post
I do single-blind tests at CES, but I find the differences are anything but subtle. Even sighted tests work...

Steve N.
Like I said, I would love to see a properly-designed double-blind test. If the results are "anything but subtle," then the differences should be easy to identify in a double-blind test. Single-blind and non-blind tests aren't conclusive.
Reply
post #27 of 112
12/19/06 at 7:38pm
Quote:
Originally Posted by sacd lover View Post
I would love to see the objectivist crowd actually listen to the equipment first rather than take measurements and assume that all is known.
Why does wanting a proper listening test make me an "objectivist"?
Reply
post #28 of 112
12/19/06 at 7:46pm
Thread Starter 
Quote:
Originally Posted by sacd lover View Post
I would love to see the objectivist crowd actually listen to the equipment first rather than take measurements and assume that all is known.
But in this case it was a listening test i.e the subjects (including musicians) listened to two signals one with and one without jitter and were unable to discern differences until the jitter was at very very very very high levels.

It almost seems as if some folks want jitter to be a problem, I just cannot fathom it, surely we should rejoice if jitter was a non-issue.
Reply
post #29 of 112
12/19/06 at 8:11pm
Thread Starter 
Quote:
Originally Posted by Febs View Post
Like I said, I would love to see a properly-designed double-blind test. If the results are "anything but subtle," then the differences should be easy to identify in a double-blind test. Single-blind and non-blind tests aren't conclusive.
Post 13 points to a ABX comparator and a number of jitter samples plus a reference sample, you can download them and try blind comparisons - the jitter samples are with 60hz jitter at -20db to -80db.
Reply
post #30 of 112
12/19/06 at 8:48pm
Quote:
Originally Posted by audioengr View Post
I for one, I am "wasting my time" on jitter because:

1) I believe it is the one thing that ultimately keeps digital audio from challenging vinyl/analog

2) I have heard the holy grail, namely inaudible jitter, only for a minute or so, but long to realize that it is truly a revelation. You have no idea how jitter mucks things up until it is completely gone.

Steve N.
Chaos theory at work. An extremely small (or minor) event can have catastrophic effects down the chain-of-causality road - a very small amount of jitter can go a long way in later effects on the sound.

Also, we perceive at varying levels. We may not initially perceive a small amount of jitter in full awareness, saying the more-jittered and less-jittered music sounds the same - while somehow intuitively sensing something may be not quite right with the more-jittered music. Repeated trials over many days of listening to more-jittered and less-jittered music will eventually bring this initial vague peception into full focus as we later realize the jittered music is really bad.

Human perception can be very unreliable - any listening tests that don't allow much listening experience to both A (very slightly more jitter) and B (very slightly less jitter) may not show discrimination abilities between the two.
Reply
New Posts  All Forums:Forum Nav:
  Return Home
  Back to Forum: Dedicated Source Components
Head-Fi.org › Forums › Equipment Forums › Dedicated Source Components › An interesting paper on jitter audibility