The three-minute pop song was shaped by the limits of shellac discs
Why do so many pop songs last about three minutes? Early 10-inch shellac discs spinning at 78 rpm held roughly that much music per side, and writers learned to fit the medium. The odd speed itself came from a 1925 electric turntable motor running at 3,600 rpm through a 46 to 1 gear.
Singles predate albums. Late 19th-century phonograph cylinders carried two to four minutes of sound, and for the first few decades of the 20th century nearly every commercial release was effectively a single; only classical works were bundled into multi-disc sets called albums. By about 1910 the 10-inch 78 had become the dominant format, because crude cutting methods and thick needles demanded fast rotation to sound acceptable.
Length stayed capped into the 1960s, when microgroove recording loosened things. In Britain The Animals released The House of the Rising Sun at 4 minutes 29 seconds in 1964, trimmed to 2 minutes 59 for America. A year later Bob Dylan and his fans insisted that the full six-minute Like a Rolling Stone go out on one side, after Columbia had tried splitting it across two.
RCA Victor launched the 7-inch 45 on March 31, 1949, as a smaller, tougher, better-sounding successor to shellac, and it swiftly beat Columbia's rival 7-inch disc at 33 and a third. RCA briefly colour-coded pressings by genre, but by 1952 all were black. Jukeboxes and teenagers made the 45 the voice of early rock and roll, and according to the New York Times sales peaked in 1974 at 200 million. Disco DJs in the 1970s adopted 12-inch singles, whose wider grooves allowed long dance mixes and resisted wear.
Downloads rewrote the rules. Capitol sold Duran Duran's Electric Barbarella as a paid download in September 1997, and Gwen Stefani's Hollaback Girl became the first platinum digital single after the RIAA began certifying them in 2004. In April 2006 Gnarls Barkley's Crazy reached number one in Britain on downloads alone. The iTunes Store counts only releases of three tracks or fewer, each under ten minutes.
Source: Single (music)
