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

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Here's an excerpt...

Posted by Wellfed on February 10, 2006 at 20:08:14

In Reply to: I dunno. posted by Jim Austin on February 10, 2006 at 19:30:41:

...from the Stereophile link I posted at the top of this thread originally authored by Robert Harley.

But how could freezing a CD possibly affect its sound quality? So what if the polycarbonate has a different structure? The data are all ones and zeros. Furthermore, uncorrected data errors are almost nonexistent in most discsci without treatment, ruling out improved data integrity as an answer. I posed these questions to Ed Meitner and got the following explanation (footnote 1).

Mechanical vibration of the disc causes the HF signal to become noisy and have excessive jitter. The HF signal is the raw signal output from the CD player's photodetector (footnote 2). By freezing a CD, the disc's mechanical resonance is lowered, improving the quality of the HF signal retrieved from the disc. Although theory states that noise and jitter in the HF signal will have no effect on sound quality—the HF signal is squared, buffered, decoded, filtered, and clocked out of another buffer with quartz-crystal accuracy—many digital designers maintain that HF signal quality does affect the sound.

Ed Meitner claims that the HF signal improvement from a cryogenically treated disc is easily measurable. I looked at the HF signal on an oscilloscope from the Esoteric P2 transport with treated and untreated discs. I could see no difference in the signal quality. However, it is very difficult to make comparisons without seeing the two HF signals side by side.

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? My questions probably reveal my technical illiteracy, if not, I'll just own up to it right here and now by confessing; I am technically illiterate.

I've again linked to the full article directly below.

• Frozen CDs?   (Open in New Window)

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