Compact Disc

Compact Disc: Changing the Music Industry


The first phonograph was invented in 1877 and twenty-one years later, the audiocassette was invented. As the twentieth century progressed, scientists began to look for a more efficient and higher quality method to reproduce sound. In records, for example, after many years of use, the sound quality significantly goes down because of the stress that the needle places on the groove. Scientists were interested in developing a medium that would not have to be touched in order to be read!
Digital Recording’s First Use

Rather than attempt to create a new analog method for sound recording, where a physical reproduction of the sound wave is created, scientists wanted to create a digital recording, where samples of the sound wave are taken and stored in binary format (1’s and 0’s). The first person to suggest this method for recording was the French mathematician Jean Joseph Fourier (1768-1830). He noted that if enough samples of a wave were taken, the wave could be exactly reproduced. In 1928, Bell Labs mathematician Harry Nyquist found out that in order to maximize the accuracy of the reproduction, each wave would have to be sampled twice. Because the human ear can only hear frequencies as high as 20 kilohertz (20,000 Hz), a sampling of 40 kilohertz, or 40,000 times a second would produce a recording that would sound perfect to the human ear (Travers 154).
During the 1970’s Sony and Phillips saw the potential of a digital recording method and decided to join forces in developing a practical solution. They also realized that by joining forces in the research that they would hopefully avoid the “standards battle” that ensued after the introduction of the VCR (See VCR). The first product of their research was the videodisk, which was a plastic disc similar to the phonograph that had spiral grooves that held the recorded information (this was analog, not digital). For playback, a laser rather than a needle, read the information and passed it on to a television. The quality of the videodisk’s picture was much better than that of a VCR, nonetheless they did not gain much popularity except in Japan (Travers 456).
A little over ten years later, during the 1980’s, Sony and Phillips released yet another product, the compact disc (CD). While the videodisk used analog methods for recording, the compact disc was recorded digitally. This enables it to have a much higher quality sound and also conserve space. The compact disc basically a thin sheet of gold or aluminum coated with a film of protective plastic or glass. A high-energy laser burns “pits” in the metallic sheet to represent the 1’s and 0’s. A “pit” is the equivalent of a 1, while a smooth, unburned area corresponds to 0. A low-energy laser in the CD player then reads these 1’s and 0’s and converts them to sound (Travers 456).
The Compact Disc Today

The compact disc has taken the music industry by storm. The format has become so popular that it has completely replaced phonographs and audiocassettes. The popularity of compact disc has even made a dent in the computer industry, it is the most common method for data storage. Because of their huge capacity, companies can put software titles that include high quality sounds and multimedia on a single disc. Still, a replacement for the compact disc is in the works. The DVD or digital versatile disc, is a double-sided disc the same size as a CD than can hold about 25 times the data of a CD. DVDs are most often used for watching movies because they are much sharper than traditional VCR’s, and they can hold a single movie in up to 7 different languages.