Phonograph record
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A phonograph record, a vinyl record, or simply a record or vinyl is an analog sound storage medium in the form of a flat disc with an inscribed, modulated spiral groove. The groove usually starts near the outside edge and ends near the center of the disc. The stored sound information is made audible by playing the record on a phonograph.
Three vinyl records of different formats, from left to right: a 12 inch LP, a 10 inch LP, a 7 inch single
Conductor and cast members of the D'Oyly Carte Opera Company with acoustic recording horn at HMV, c. 1924
Emile Berliner with disc record gramophone
Hungarian Pathé record, 90 to 100 rpm
Revolutions per minute
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Revolutions per minute is a unit of rotational speed for rotating machines.
One revolution per minute is equivalent to 1/60 hertz.
A car's tachometer marked in multiples of a thousand rpm