Multitrack recording devices are available with varying capacities (number of simultaneous tracks available for recording). When recording a segment of audio, which is also known as a track, audio engineers and musicians may select which track or tracks on the device will be used.
Each of the tracks avaiable on the recording device may be set to record or to playback. For example, a musician may record onto track 2 and listen on track 1 at the same time. This allows the musician to sing or to play a duet in harmony with a performance already recorded on track 1.
Both performances can then be played back perfectly synchronised, as if they had been played together. This is a type of overdubbing and can be repeated until all of the tracks are used up.
The first musician to use multitrack technology was guitarist Les Paul. The earliest multitrack recorders were analog magnetic tape recorders with 2 or 4 tracks. Today multitracks can be analog or digital, and are available with many more tracks. Analog multitracks can have up to 24 tracks and use magnetic tape which is up to 2 inches wide. Digital multitracks can record to and playback from a number of media and formats including digital tape, hard disk, and optical disk.