英語時(shí)差:新舊數(shù)字音樂
Before MP3s and other forms of digitized music there were CDs. Before CDs came vinyl records. And before vinyl? Most of us are not nearly old enough to remember, but in the early years of the twentieth century popular songs such as "By the Light of the Silvery Moon" were recorded on shellac discs and wax cylinders. Many of these early recordings still exist, but with each passing year they grow more fragile and likely to fall apart while being played. Consequently, music archivists are faced with a delicate problem: how to preserve old-time recordings without silencing them forever? Enter Carl Haber and Vitaly Fadayev, particle physicists at the University of California, Berkeley who happened to hear a radio piece on the preservationist's dilemma. These music-loving physicists suspected that the techniques they use to make sensors that track subatomic particles might help the troubled archivists. With the aid of a powerful microscope they mapped out the grooves of an old 78 RPM shellac disk and the grooves on a wax cylinder recorded in 1909. After digitally reproducing the mapped grooves on a computer, Haber and Fadayev then created software to mimic the effect of a needle moving in the mapped grooves in order to re-create the sounds. Incredibly, the digitized version sounded even better than the original recordings. And as the mapping technique improves, the physicists hope to enable the digital preservation of large amounts of endangered music. So even if you don't remember the dark ages before CDs, you may soon be able to enjoy down-loadable old-time music, courtesy of the digital revolution.
