Frozen CDs? Page 3

While we're on the subject of CD tweaks, I mentioned in my article in Vol.13 No.5 ("CD: Jitter, Errors, and Magic") that a Japanese company called HiBright was making CDs with a proprietary material called Amorphous Poly Olefin (APO) that reportedly offers better sound than conventional polycarbonate. At the time of that writing, I had not heard discs made with this material. However, I now have two copies each of two different discs (footnote 5), one made with polycarbonate and the other with APO, but both pressed from the same stamper.

Interestingly, the disc made from APO was smoother and less bright than the polycarbonate disc. This is the opposite reaction I had to the Museatex frozen and painted disc. With the APO disc, female vocal was more open, had more air around it, and was much less sibilant. Although both polycarbonate and APO versions were excruciatingly bright, the disc made from APO was far less annoying. The spitty edge to the voice was greatly reduced, and the presentation took on a more relaxed character. The tonal difference was similar to an equalization change of about 2dB at 10kHz. These impressions were consistent with both disc pairs I auditioned.

A fellow audiophile had a similar experience with pairs of HiBright polycarbonate and APO CDs. He found it difficult to believe that such different-sounding discs could have been made from the same stamper. The difference was so great, he believed that one disc had been equalized. Furthermore, he was highly skeptical that the disc composition could have any audible effect. To verify that the discs were indeed identical (except for the molding material), he sent the discs to a facility to have their data compared to each other. This process is routinely performed on Compact Disc Read-Only Memory discs (CD-ROMs) to assure that replicated discs are identical (down to the last bit) to the source data.

The data comparison revealed that the two discs were, bit for bit, identical to each other. Since the polycarbonate and APO discs have identical data, that is conclusive proof that no equalization or other processing could account for the musical differences. Since they obviously have different sonic characteristics but contain identical data, there are therefore unknown phenomena occurring in CD playback not accounted for in textbook digital-audio theory.

Finally, there is one more CD tweak on the horizon, also created by Museatex: abrading a CD's edges and the non-label side surface only where data have not been recorded. This reportedly causes light to be diffracted rather than deflected at the roughened surfaces. Eighty-grit sandpaper is used on the vertical edges, and 200 grit on the read (bottom) surface. I am told that the record label Chandos is working with Swiss CD pressing plant ICM to mold a roughened surface into the polycarbonate during CD manufacturing. Stay tuned.

My fascination with CD tweaks stems not from their intrinsic abilities to improve CD sound as much as it comes from the realization that if any tweak has even the slightest audible effect, conventional digital audio theory is turned upside down. More important, however, the widespread acceptance and belief in CD tweaks may make skeptical engineers listen for themselves, perhaps sparking an investigation into why they work. Such research may lead to fundamental new discoveries in digital audio that will drastically improve its performance. With LPs all but dead, there is an imperative to make digital audio sound better.

Furthermore, I see CD tweaks as a Rosetta Stone (footnote 6) to an audio engineering establishment that dismisses the possibility that freezing a CD, or painting it black, or putting green paint around the edge, or making it from a different material, could affect its sound. Because these treatments are considered the epitome of audiophile lunacy and because they are readily audible, some measurement-oriented scientists may, if they listen for themselves, realize that audiophiles are not always the demented mystics they are often accused of being. Consequently, some scientists may decide to turn their considerable analytical skill toward other areas of audio reproduction, long cited by audiophiles as important, that are far less bizarre than freezing CDs.



Footnote 5: They are The VIP Trio, ACB-0003 (APO) and PCB-0003 (polycarbonate) with Cedar Walton, Pat Senatore, and Billy Higgins; and Algeria by Sunny Wilkinson, ACB-7 (APO) and PCB-7 (polycarbonate). Both CDs are on HiBright's California Breeze label.—Robert Harley

Footnote 6: The Rosetta Stone is a basalt slab with the same information inscribed in Egyptian hieroglyphics, Demotic, and Greek. Written in about 200 BC and discovered in Egypt by Napoleon's soldiers in 1799, it provided a means of deciphering hieroglyphics which were previously unintelligible. The Rosetta Stone was the key to understanding the writings of ancient culture and civilization. Just as the Rosetta Stone provided a bridge to understanding a previously unexplored civilization, CD tweaks may break down the barriers between the audiophile and the scientist. We could use a few converts in the quest to make music reproduction less of a black art.—Robert Harley

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