More Inventions (III)

Phonograph 

Phonographs are also called record players and are devices that reproduce sounds that have been recorded on audio records. During the mid-1980's,phonographs were very popular for listening to music and other sound recordings. Today they have been replaced by cassette tapes and compact discs. Sounds produced by Compact disc players are better than phonographs and are more durable .However phonographs are still used. 

Its history

U.S. inventor Thomas A. Edison produced the first phonograph in 1877. MR. Edison recorded sound on tinfoil wrapped around a small metal cylinder, and this could be replayed . The whole system involved a cylinder rotated on an axle that was turned with a hand crank. These vibrations created sounds roughly like the original sound. This type of recording is called acoustic recording because the sound is produced without electrical energy. 

In 1885, the U.S. scientists Chichester Bell and Charles S. Tainter improved upon Edison's invention by recording on cardboard cylinders coated with wax. This new recording material produced better sound. 

In 1887, Emile Berliner, a German immigrant to the United States, invented the Gramophone--a phonograph that used shellac discs. These discs provided better sound, were more durable, and could be mass-produced more easily than could cylinders. 

The first electrically recorded phonograph records appeared in 1925. In addition, manufacturers began producing phonographs with electric motors and amplifiers, which greatly improved the quality of recorded sound. 

Until 1948, most commercial disc recordings were made of a mixture of clay and shellac and were played at 78 rpm. In that year, the plastic 331/3-rpm LP record appeared on the market. It had been developed at the Columbia Broadcasting System Laboratories under the direction of Peter Goldmark, a U.S. electrical engineer.  The LP held much more recorded sound and was more durable than the 78-rpm disc. In 1949, the 45-rpm disc was introduced by Radio Corporation of America (now RCA Corporation) to compete with the LP.  

Growing interest in high fidelity in recorded sound led to the appearance of stereophonic phonographs and discs in 1958. Previously, records and phonographs were monaural, or monophonic. Such records and record players reproduce sounds from only one channel. By the late 1960's, almost all new phonographs and records were stereophonic. 

Audio compact discs were introduced in Japan and Europe in 1982, and in the United States in 1983. Their superior sound quality and durability quickly made them popular. Today, few new recordings are issued on phonograph records.