The phonograph, in its later forms also called a gramophone or record player, 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 acoustic phonographs, the stylus vibrated a diaphragm which produced sound waves which were coupled to the open air through a flaring horn, or directly to the listener's ears through stethoscope-type earphones. In later electric phonographs, the motions of the stylus are converted into an analogous electrical signal by a transducer called a pickup or cartridge, electronically amplified, then converted 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.In the 1890s, Emile Berliner initiated the transition from phonograph cylinders to flat discs with a spiral groove running from the periphery to near the center. Other improvements were made throughout the years, including modifications to the turntable and its drive system, the stylus or needle, and the sound and equalization systems.The disc phonograph record was the dominant audio recording format throughout most of the 20th century. From the mid-1980s, phonograph use declined sharply because of the rise of the compact disc and other digital recording formats. While no longer mass-market items, modest numbers of phonographs and phonograph records continue to be produced in the second decade of the 21st century.