In a room you’re not allowed to go in, inside a machine you’re not allowed to look at, a 30-milliwatt laser beam that you’d barely be able to see anyway is burning infinitesimally small indentations into a spinning plate of glass. The indentations aren’t into the glass, exactly–as the laser switches on and off, the light is actually exposing tiny dots on an extremely thin layer of clear, light-sensitive coating. And they’re not dots, really, they’re more like flattened Good & Plentys of varying lengths.
The plant sits on the outskirts of Terre Haute, a blue-collar town of about 60,000; it’s a vast, low-slung affair, set back from Fruitridge Avenue by a large parking lot. There’s nothing on the outside to suggest it, but this is one of the two or three largest CD factories in the world, the source of about 30 percent of all the CDs bought in America last year. Inside, a bit more than 700 people work in four-day shifts of 12 hours each; the plant runs 24 hours a day, seven days a week, producing 120 million compact discs a year, nearly 250 per minute.
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But making a compact disc is of an altogether different order. A CD, in a way, has very little to do with music–it’s a high-tech information storage and retrieval system much more analogous to computer discs than to records or cassette tapes. Indeed, compact discs would be even more like computer discs if sound weren’t so demanding in terms of storage. For the purposes of CD-ROM–the ROM stands for “read-only memory,” which means you can access the information but not change it–a CD-sized disc can store the Encyclopaedia Britannica. By contrast a music CD, physically identical to a CD-ROM, holds a maximum of about 70 minutes of music.
The problematic sounds range from distortion on a guitar to the kind of stuff that bands think is neat but that sound engineers just roll their eyes at.
Time out for a little CD background.
