record player

A record player is an obsolete device, generically similar to a CD player. Records are disks of vinyl which have a single groove running spirally from the outside edge to the center. The disk is rotated at constant RPMs (typically 33 or 45) by a mechanical spindle which pierces the disk through a premade hole.

The groove is inscribed with an amplitude-modulation image of the sound wave. A diamond stylus mounted on an arm mechanically follows the waves in the groove; the stylus actuates either a piezoelectric crystal or an electromagnet. The resulting signal is amplified to audibility. Records allowed a fairly good sound quality, but were subject to mechanical wear and to clicks and pops resulting from dust on the record or scratches from the misuse of the stylus arm.