Double album

A double album (or double record) is an audio album which spans two units of the primary medium in which it is sold, typically records and compact discs. A double album is usually though not always released as such, because the recording is longer than the capacity of the medium. Recording artists often think of double albums as comprising a single piece artistically; however, there are exceptions such as John Lennon's Some Time in New York City and Pink Floyd's Ummagumma (both examples of one studio record and one live album packaged together) and OutKast's Speakerboxxx/The Love Below (effectively two solo albums, one by each member of the duo). A classic example of this idea is Works (Volume One) by Emerson Lake and Palmer, where side one was Keith Emerson, two Greg Lake, three Carl Palmer while side four was by the entire group.

Since the advent of the compact disc, albums are sometimes released with a bonus disc featuring additional material as a supplement to the main album, with live tracks, studio out-takes, cut songs, or older unreleased material. One innovation is the accompaniment of a CD with a DVD of related material, such as video related to the album or DVD-Audio versions of the same recordings. These could be regarded as a new form of double album; some such discs were also released on a two-sided format called DualDisc. Due to the limitations of the gramophone record, many albums primarily released on the format were under 40 minutes long. This has led to record labels re-releasing two of these albums on one CD, thus making a double album. The same principles apply to the triple album, which comprises three units. Packages with more units than three are often packaged as a box set.

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