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The phonograph is a device invented in 1877 for the mechanical recording and reproduction of sound. In its later forms it is also called a gramophone (as a trademark since 1887, as a generic name since c. 1900). The sound vibration waveforms are recorded as corresponding physical deviations of a spiral groove engraved, etched, incised, 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 (also known as record players (since 1940s) or, most recently, turntables〔Names "record player" and "turntable" have gradually become synonymous, however the second one is better associated with devices requiring separate amplifiers and/or loudspeakers. Originally, the term "turntable" referred to the part of phonograph's mechanism providing rotation of the record.〕), 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.〔(【引用サイトリンク】publisher=Rutgers University )〕〔(【引用サイトリンク】publisher=Library of Congress )〕〔(【引用サイトリンク】publisher=Gerald Beals )〕 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 wrapped around a rotating cylinder. A stylus responding to sound vibrations produced an up and down or hill-and-dale groove in the foil. 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" groove around 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. == Terminology == Usage of terminology is not uniform across the English-speaking world (see below). In more modern usage, the playback device is often called a "turntable," "record player," or "record changer." When used in conjunction with a mixer as part of a DJ setup, turntables are often called "decks." The term ''phonograph'' ("sound writing") was derived from the Greek words ("sound" or "voice" and transliterated as ''phonē'') and (meaning "writing" and transliterated as ''graphē''). The similar related terms ''gramophone'' (from the Greek γράμμα, ''gramma'', "letter" and φωνή, ''phōnē'', "voice") and ''graphophone'' have similar root meanings. The roots were already familiar from existing 19th-century words such as ''photograph'' ("light writing"), ''telegraph'' ("distant writing"), and ''telephone'' ("distant sound"). The new term may have been influenced by the existing words ''phonographic'' and ''phonography'', which referred to a system of phonetic shorthand; in 1852 ''The New York Times'' carried an advertisement for "Professor Webster's phonographic class," and in 1859 the New York State Teachers Association tabled a motion to "employ a phonographic recorder" to record its meetings. Arguably, any device used to record sound or reproduce recorded sound could be called a type of "phonograph," but in common practice the word has come to mean historic technologies of sound recording, involving audio-frequency modulations of a physical trace or groove. In the late 19th and early 20th centuries, "Phonograph," "Gramophone," "Graphophone," "Zonophone" and the like were still brand names specific to various makers of sometimes very different (i.e., cylinder and disc) machines; so considerable use was made of the generic term "talking machine," especially in print. "Talking machine" had earlier been used to refer to complicated devices which produced a crude imitation of speech, by simulating the workings of the vocal cords, tongue, and lips – a potential source of confusion both then and now. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Phonograph」の詳細全文を読む スポンサード リンク
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