Improvement of CD sound quality : Color the edges?
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Claim: Coating the edges of a compact disc with a green marking pen will noticeably improve its sound quality.
Status: False.
Origins: Despite
numerous claims about the efficacy of "greening" CDs, there is no valid scientific reason to explain why marking CDs with green pens would improve sound quality, nor has anyone ever been able to consistently distinguish between marked and unmarked discs in a double blind comparison.
The most commonly offered explanation for the allegedly improved results produced by a "greened" CD is that the light from a CD player's laser reflects off the shiny inner rim and outer edge of the CD and enters the "eye" of the player, thereby altering the digital bit count and distorting the sound. Coating the edges of the CD with a colored marker supposedly reduces or eliminates the amount of stray light reflecting of the disc's edges, producing "better" or "cleaner" sound. (Green markers are used because the faithful believe that color most effectively "absorbs" the light from the laser's infrared beam.) As former Stereo Review and High Fidelity editor David Ranada pointed out, however, light travels so quickly that it would be reflected back to the laser from the edge of the disc while the laser was still reading the same digital bit and therefore could not produce a distorted reading. Ranada confirmed his assertion by connecting a digital error counter to a CD player to compare data errors produced during playback of both colored and uncolored discs. He found no difference between the two types of discs at any portion of their surfaces -- inner rim, outer rim, or middle. He also tried coloring only half the circumference of a disc and using an oscilloscope to analyze the signal picked up by the laser. The scope showed no difference between the patterns produced by the colored and uncolored halves of the disc.
The claim that coloring CDs could improve their sound originated in late 1989, was spread at the winter Consumer Electronics Show in Las Vegas in early 1990, and achieved national prominence when it was printed (and given credence) in the March 1990 issue of ICE (the International CD Exchange newsletter). The initial claims suggested that the inner rim and outer edge of the disc should be colored with an Eberhard Faber Design Art Marker No. 255, but over time this procedure became less specific. (Many later reports mentioned coloring only the outer rim, and the pen used was either generic green or a competely different color altogether, such as purple. Coating discs with Armor All or Rain-X were other popular variations.) -
This is really dumb.
Of course the CD sound quality can't be improved.
Everthing is digital. The only thin g to improve the quality is to first improve the recording standard.
Done that?
Then next is to upgrade to a better amplifier and speakers or hifi.