Audio

Sound recording and reproduction is the electrical or mechanical inscription and re-creation of sound waves, such as spoken voice, singing, instrumental music, or sound effects. The two main classes of sound recording technology are analog recording and digital recording. Acousti analog recording is achieved by a small microphone diaphragm that can detect changes in atmospheric pressure (acoustc sound waves) and record them as graphic sound waves on a medium such as a phonograph (in which a stylus senses grooves on a record) or magnetic tape (in which electrical current waves from the microphones are converted to electromagnetic fluctuation (flux) that modulate an electric signal.
Analog sound reproduction is the reverse process, with a bigger loudspeaker diaphragm causing changes to atmospheric pressure to form acoustic sound waves. Electronically generated sound waves may also be recorded directly from devices such as an electric guitar pickup or a synthesizer, without the use of acoustics in the recording process other than the need for musicians to hear how well they are playing during recording sessions.
Digital recording and reproduction uses the same analog technologies, with the added digitization of the sonographic data and signal, allowing it to be stored and transmitted on a wider variety of media. The digital binary numeric data is a representation of the periodic vector points in the raw analog data at a sample rate most often too frequent for the human ear to distinguish differences in quality.
Digital recordings are not necessarily at a higher sample rate, but are often considered higher quality because of less interference from dust or electromagnetic interference in playback and less mechanical deterioration from corrosion or mishandling the storage medium. A digital audio signal (when converted) resembles an analog signal, unlike a pure binary digital signal which would only be perceived as a buzzing noise by the human ear.