An audio
tape recorder,
tape deck or
tape machine is an
audio storage device that records and plays back sounds, including articulated voices, usually using
magnetic tape, either wound on a reel or in a
cassette, for storage. In its present-day form, it records a fluctuating
signal by moving the tape across a
tape head that polarizes the
magnetic domains in the tape in proportion to the audio signal. Tape-recording devices include
reel-to-reel tape deck and the
cassette deck.