Audio gd Sparrow Blind Test - Page 34  

 

Quote:

Originally Posted by Head Injury 

At least not for whoever took the test, and presumably the population as a whole if enough other people fail as well.

That's a big if, and the source of most of the controversy in this thread IMHO.

But would you agree that "jitter reduction" is more important that "bit-perfect" when discussing optimum digital/analog reproduction?

Quote:

Originally Posted by grokit 

But would you agree that "jitter reduction" is more important that "bit-perfect" when discussing optimum digital/analog reproduction?

No, because I don't know if either do anything audible.

I will say that bit-perfect is useful for measurements. And important for one's own critical listening if only to make sure there's nothing unwanted like EQ or processing in the background potentially coloring things. If there's nothing like that, then I think the differences are minimal and inaudible. At least I could never tell the difference without expecting it to be placebo.

Quote:

Originally Posted by Head Injury 

No, because I don't know if either do anything audible.

 

I will say that bit-perfect is useful for measurements. And important for one's own critical listening if only to make sure there's nothing unwanted like EQ or processing in the background potentially coloring things. If there's nothing like that, then I think the differences are minimal and inaudible. At least I could never tell the difference without expecting it to be placebo.

The s/pdif reclocking bunch may beg to differ, lol.

Placebo or not, I am hoping to discern a difference with the Bravo s/pdif reclocker and the usb isolator that I have on order to go with my new (to me) Bel Canto DAC 2; I will be doing a lot of (subjective of course) comparisons with other gear like the uDac as a s/pdif converter, and my Mini-i 

To get right back on topic (there are loads of threads on jitter) thanks to AVU for your test. Could you please post about you methology so I can add this thread to the one on audiophile myths.

Anyone else with an Audio gd Sparrow want to do another blind test?

Quote:

Originally Posted by grokit 

 

Here's one: this paper by Julian Dunn

 

Linked to from a decent article that touched upon the subject pretty extensively:

"Jitter has always been and still is the worst enemy of the digital audio format. And today it is fully understood. Jitter can only cause loss in audio quality at the A/D and D/A conversion process."

 

Also be sure and check out:

"It turns out that timing errors in the picosecond (ps) range—the time it takes light to travel inches—can audibly degrade digitally reproduced music. These timing errors—called jitter—are only now beginning to be understood (footnote 1)."

 

These folks seem to know what they are talking about, and have studied the subject objectively and yes, conclusively.

I am sorry but the evidence for readily audible jitter in commercially available kit is just not **empirically** supported by any of the links you cite , all of which I am fully familiar with and I have also read pretty much all of Dunn's papers on jitter. Dunn NEVER backed up his models with any controlled listening tests, Dunn also changed his views on audibility after reading Benjamin and Gannon's 1998 paper which did include controlled listening tests and placed the theshold for sinusoidal (correlated - the worst kind) jitter detection at around 20ns in music or 10ns for a high frequency pure tone , far higher than Dunn's model. Dunn's audibility model was also predicated on using a music level of 120db above the threshold of hearing, for most settings this is in excess of 140db. Be that as it may, no ***controlled*** test to date has shown jitter (random or correlated) to be audible at the levels found in half competent audio kit[1]. When you talk about random jitter the detection threshold is even higher than that (Ashihara et al, 2005) since this type of jitter is basically heard as noise.

1 - A famous exclusion to this is the McIntosh MS750 music server which sports jitter levels of over 14ns with one type of connector but this is so bad technically elsewhere that jitter is the last of its problems...

OK, since we are going to stay with jitter, there is also no proven correlation between jitter rate and sound quality. It is generally assumed that low jitter = better SQ, but you have got to prove that somehow.

Quote:

Originally Posted by Prog Rock Man 

OK, since we are going to stay with jitter, there is also no proven correlation between jitter rate and sound quality. It is generally assumed that low jitter = better SQ, but you have got to prove that somehow.

In absolute terms higher jitter does degrade **measured** sound quality, what you get is extra noise and or distortion and above certain levels jitter degrades the SQ to the point that a 16 bit file actually becomes effectively a <16 bit file, in fact you need very little jitter to do this according to Dunn's model at 20khz 20ps is sufficient. At lower frequencies jitter has to be much higher, for 20 bit and 24 bit files jitter needs to be much lower. Of course none of this means that you can hear the difference.