Content and scope
Songs included on a compilation album may be previously released or unreleased, usually from several separate recordings by either one or several performers. If by one artist, then generally the tracks were not originally intended for release together as a single work, but may be collected together as a greatest hits album or box set. If from several performers, there may be a theme, topic, or genre which links the tracks, or they may have been intended for release as a single work—such as a tribute album. When the tracks are by the same recording artist, the album may be referred to as a retrospective album or an anthology. Compilation albums may employ traditional product bundling strategies.
According to sound technician Richard King, classical music compilations "may require more processing to match tracks coming from various sources and recording venues as well as the different sizes of ensembles."