Propeller Head Plaza Technical and scientific discussion of amps, cables and other topics.

---

[ Follow Ups ] Thread: [ Display  All  Email ] [ Propeller Head Plaza ]

---

[ Alert Moderator ]

---

Why rule out data integrity?

Posted by Jim Austin on February 11, 2006 at 05:16:44

In Reply to: Here's an excerpt... posted by Wellfed on February 10, 2006 at 20:08:14:

>>What is the difference, if any, between "uncorrected data errors" and
"excessive jitter"? Why can Robert Harley rule out improved data integrity as the answer?<<

In the article I posted (which was written about the same time as the "frozen CD's" article) RH checks out the issue of data integrity exhaustively. He learns that irrecoverable data errors are quite rare, and that none of the tweaks he tried made any positive difference (though the disc-treatment liquids appeared to have a negative effect). It's probably based on that experience that he dismissed the possibility of data integrity as making a difference on thse frozen CDs. Data integrity is rarely an issue.

There really are two "data integrity" issuss: whether you ultimately get the data right (or require the error-correction software to make data up) and whether you make the transport read the data several times in order to get it right.

Jitter is a time-axis issue: it arises from slight offsets in the beginning and end of each separate data point. It is measurable via sidebands that appear in certain spectra (lots of information on how these measurements are made on the Steroephile Web site). These sidebanda are how you measure it, but that doesn't mean they're the only effect. One of the Stereophile test CDs has an example of a pure tone with jitter superimposed; you can hear it, but a pure tone probably doesn't reveal the full effects of jitter.

Interestingly, in the "tweaks" essay RH found that there were dramatic differences in jitter between different discs from different sources, and that compared to these differences ANY other changes in the amount of jitter were pretty much insignificant. And the tweaks he tried had no significant effect on jitter.

As for the mechanical resonance issue: it's plausible--there's a direct relationship between the stiffness of a material and the mechanical resonance. But I'm ekeptical of this interpretation; these effects occur at frequencies where I wouldn't expect to see an effect.

Though I respect RH and others who have reached the same conclusion, I'm reluctant to rule out the placebo effect.

Jim

This post is made possible by the generous support of people like you and our sponsors:

Parts Connexion

---

[ Top of Page ] [ Contact Us ] [ Support/Wish List ] [ Copyright © 2024, Audio Asylum, all rights reserved ]

---

[ General ] [ Speakers ] [ Tubes ] [ Vinyl ] [ Digital ] [ Hi-Rez ] [ Video Asylum ] [ Cables ] [ Tweaks/DIY ] [ Music ] [ Films ]

---