Phonograph, also known as record player, electromechanical instrument for reproducing sound from a record. A record is a vinyl disk that has a spiral groove with tiny bumps on the walls of the groove; the bumps encode a musical or other type of recording. has four principal components: the turntable, the tonearm, the stylus, and the amplifier, although an amplifier is not always incorporated into the instrument.
The turntable is a flat, circular platform upon which the record is placed. An electric motor rotates the turntable at constant speed, usually 332, 45, or 78 revolutions per minute (rpm). The tonearm is a rod with a jewel-tipped stylus, or needle, at its free end. The tonearm either pivots to keep the stylus in the record groove, or is suspended by a mechanism that enables it to stay oriented in the same direction while it moves across the record. When the stylus moves along the undulating groove of the revolving disk, it vibrates, and the vibrations are converted into equivalent electrical impulses by the cartridge in the tonearm. These impulses are conducted by wire leads to an electronic amplifier and then to one or more loudspeakers.
The first practical phonograph was built by the American inventor Thomas Edison in 1877. Edison recorded sound on a cylinder, which was then rotated against a needle. The needle moved up and down in the grooves of the cylinder, producing vibrations that were amplified by a conical horn. Because of the vertical movement of the needle, this recording method was called the "hill-and-dale" process.
Edison had intended the phonograph to be used primarily as a dictating machine in offices. However, with the invention of the flat-disk phonograph, or gramophone, by the German-born American inventor Emile Berliner in 1887, the phonograph began to develop as an artistic medium for recording the great singers and musical instrumentalists of the time. The gramophone played records at 78 rpm, and the needle moved laterally (from side to side) in a groove of even depth. Like the cylinder phonographs, it reproduced sound with a needle whose mechanical vibrations were amplified by using a cone-shaped horn. Most such phonographs, moreover, were driven by spring motors and required rewinding. The records were made of shellac and broke easily.
Despite such limitations, the phonograph became increasingly popular in the United States, largely as a result of the production of a huge collection of recorded musical pieces by American and European record companies. The companies employed the greatest singers of Europe and the United States, such as the Italian dramatic tenor Enrich Caruso.
A wide variety of phonographs were also produced in Europe. In France, a gramophone was developed in which the needle traveled across the record from the center to the rim, reversing the usual process, and in which the record revolved at 90 rpm; this machine produced sound of very high quality for the period. Swiss music-box manufacturers specialized in the production of small portable phonographs.
The immense success of the phonograph led to demands for improved sound. About 1920, the old mechanical process began to be replaced by electrical recording and reproduction, in which the vibrations of the phonograph needle were amplified by electromagnetic devices instead of a horn. The 78-rpm records continued to be used, however, until the invention of the first fully practical long-playing record about 1948.
The operation of a sound-recording system may, however, be m ffb ost easily understood by considering the process of recording sound by the now obsolete mechanical method. In this method, sound waves are used directly or indirectly to actuate a stylus or cutter that engraves on a disk or cylinder a wavy-line pattern corresponding to the pattern of sound waves. This process, with minor modifications, was used for many years in the production of phonograph records. In the direct method of mechanical recording, sound waves strike a very light diaphragm of metal or other substance and set it into motion. Attached to the diaphragm is a needle or cutting point that vibrates with the diaphragm. Under the point is a disk or cylinder of wax, metallic foil, shellac, or other suitable substance that is moved past the needle so that the needle cuts a groove in the form of a spiral on a disk, or a helix on a cylinder. As the needle vibrates it traces a wavy groove laterally or vertically in the record; this groove is a mechanical replica of the sound that struck the diaphragm of the recording machine. If, for example, the sound wave consists of the musical tone of A in the treble clef, which has a frequency of 440 Hz (hertz or cycles per second), the needle ...