A back track or backing track is an audio recording on audiotape, CD or a digital recording medium or a MIDI recording of synthesized instruments, sometimes of purely rhythmic accompaniment, often of a rhythm section or other accompaniment parts that live musicians play along with or sing along to. Backing tracks enable singers and bands to add parts to their music which would be impractical or impossible to perform live, such as string section or choir parts which were recorded in the studio. A backing track can be used by a one person band (e.g., a singer-guitarist) to add any one or more of bass, drums and keyboards to their live shows without the cost of hiring extra musicians. A small pop group or rock band (e.g., a power trio) can use backing tracks to add a string section, horn section, drumming or backing vocals to their live shows.
Bands or solo musicians may use backing tracks to add extra instrumental or vocal tracks to a live performance, to enhance the sound (as in the employment of doubled backing vocals) or to replicate more closely the instrumentation heard on a recording (as in the use of additional recorded parts such as string sections which would be costly to reproduce live.) A singer or vocal group performing without a backup band may sing along to pre-recorded music.