The Technofile Web site has moved. The invention of the compact disc brought a new era to high fidelity, but it didn't get rid of one of the biggest problems in audio the error-prone tape recorder.
CDs start out life as tape recordings.
After a couple of copies from one tape recorder to the next, the final version is put on yet another tape recorder and sent to the CD mastering plant. In most cases these days, all the tape recorders in this chain are digital. That's good news and bad news. It's good because digital recorders handle sound very well. And it's bad because successive copies of digital tapes, from one recorder to another, can make the sound gritty.