Type of music release usually containing one or two tracks
45 rpm single record with large central hole as used in the US for jukeboxes
In the music industry, a single is a type of release, typically a song recording of fewer tracks than an LP record or an album. This can be released for sale to the public in a variety of different formats. In most cases, a single is a song that is released separately from an album, although it usually also appears on an album. Typically, these are the songs from albums that are released separately for promotional uses such as digital download or commercial radio airplay and are expected to be the most popular. In other cases a recording released as a single may not appear on an album.
Despite being referred to as a single, singles can include up to as many as three tracks. The biggest digital music distributor, iTunes Store, accepts as many as three tracks less than ten minutes each as a single, as does popular music player Spotify. Any more than three tracks on a musical release or thirty minutes in total running time is either an extended play (EP) or, if over six tracks long, an album.
Historically, when mainstream music was purchased via vinyl records, singles would be released double-sided. That is to say, they were released with an A-side and B-side, on which two singles would be released, one on each side. Moreover, traditionally, only the most popular songs from a previously released album would be released as a single. In more contemporary forms of music consumption, artists release most, if not all, of the tracks on an album as singles.
The basic specifications of the music single were set[vague] in the late 19th century, when the gramophone record began to supersede phonograph cylinders in commercially produced musical recordings. Gramophone discs were manufactured with a range of playback speeds (from 16 rpm to 78 rpm) and in several sizes (including 12-inch/30 cm). By about 1910, however, the 10-inch (25 cm), 78 rpm shellac disc had become the most commonly used format.
The inherent technical limitations of the gramophone disc defined the standard format for commercial recordings in the early 20th century. The relatively crude disc-cutting techniques of the time and the thickness of the needles used on record players limited the number of grooves per inch that could be inscribed on the disc surface, and a high rotation speed was necessary to achieve acceptable recording and playback fidelity. 78 rpm was chosen as the standard because of the introduction of the electrically powered, synchronous turntable motor in 1925, which ran at 3600 rpm with a 46:1 gear ratio, resulting in a rotation speed of 78.26 rpm.
With these factors applied to the 10-inch format, songwriters and performers increasingly tailored their output to fit the new medium. The 3-minute single remained the standard into the 1960s, when the availability of microgroove recording and improved mastering techniques enabled recording artists to increase the duration of their recorded songs. The breakthrough came with Bob Dylan's "Like a Rolling Stone". Although CBS tried to make the record more "radio friendly" by cutting the performance into halves, and separating them between the two sides of the vinyldisc, both Dylan and his fans demanded that the full six-minute take be placed on one side, and that radio stations play the song in its entirety.