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The phonograph is a device introduced in 1877 for the mechanical recording and reproduction of sound. The sound vibration waveforms are recorded as corresponding physical deviations of a groove engraved or impressed into the surface of a rotating cylinder or disc. To recreate the sound, the surface is similarly rotated while a playback stylus traces the groove and is therefore vibrated by it, very faintly reproducing the recorded sound. In early non-electronic phonographs, the slight vibrations of the stylus are physically coupled to the air generally, or to the listener's ears directly, by acoustical means which greatly increase their audibility; in later phonographs, the motions of the stylus are converted into an analogous electrical signal by a transducer called a pickup or cartridge, electronically amplified, then transduced back into sound by a loudspeaker. The phonograph was invented in 1877 by Thomas Edison. While other inventors had produced devices that could record sounds, Edison's phonograph was the first to be able to reproduce the recorded sound. His phonograph originally recorded sound onto a tinfoil sheet phonograph cylinder, and could both record and reproduce sounds. Alexander Graham Bell's Volta Laboratory made several improvements in the 1880s, including the use of wax-coated cardboard cylinders, and a cutting stylus that moved from side to side in a "zig zag" pattern across the record.
