Long-playing records play for a long time, enabling records with more than one song.
Background
As Edison’s phonograph evolved, the recordings eventually migrated to small disks played at 78 rotations per minute (rpm). Each disk held about three minutes of music per side.
Filmmakers wanted to add sound to their movies. Before then, movies ran and typically a musician played a piano or organ. Lee de Forest’s Audion amplifying tube made movie sound possible, but the three-minute recordings were too short.
In the early 1920s, de Forest tried to create his own extended-play sound system, but it never worked well. In response, Bell Labs created a longer playing disk. Significantly larger disks spun slower, at 33 1/3 rpm allowing it to play about 23 minutes. They branded it the “Vitaphone” sound system for movies.
The Vitaphone system functioned from 1926 to 1931. Eventually, optically encoding a soundtrack replaced the LP movie soundtrack. Optical encoding made it easier to synchronize sound to movies and played for an indefinite length.
LP’s, from B2B to B2C
However, the long-playing records caught on a consumer product. It was impossible to record entire classical pieces on the 78rpm records. Additionally, pop soundtracks contained one song per side. Finally, the maximum song length was about three minutes. To sell multiple songs, the small records would be bound together into a book, called an album, a term still in use.
Over the years, various recording technologies attempted to challenge the dominance of the LP record except none succeeded besides cassette tapes, which could play in cars. In 1982, the introduction of the digital Compact Disk (CD) eventually sent the LP into obsolescence.
Interestingly, vinyl LP records are becoming popular again. Starting in 2014, vinyl record sales climbed steadily higher due to a perception of better-quality sound. By 2018, vinyl accounted for 9.7 million album sales, up 12% from 8.6 million in 2017. In contrast, CD sales are falling by 41% per year. In 2018, CD sales are 70% and vinyl sales account for 30% of the physical music media. However, by 2018 overall sales of physical music – as opposed to digital soundtracks or streaming – makeup only 10% of the industrial total.