Columbia's 33⅓ microgroove LP won by fitting a symphony on one disc.

Before 1948 the standard record was the 78 rpm shellac disc, which held only a few minutes per side. Longer works such as symphonies and operas had to be spread across many discs, and each one could shatter.

Columbia Records, with CBS Laboratories engineer Peter Goldmark, introduced the LP in 1948. The design used a much narrower groove and played at 33⅓ revolutions per minute, so a 12-inch unbreakable vinyl disc could play about twenty to twenty-five minutes a side.

This made a single record the natural format for concerts, operas and albums. A rival 45 rpm format emerged for singles, but the LP's long-playing capacity made it the standard for full-length albums, and it displaced the 78.

Fit a whole work on one unbreakable disc

The narrower microgroove and slower speed let far more audio fit on each side.

Unbreakable vinyl was safer and lighter than shellac, and lower in surface noise.

A whole symphony on a disc was a better product, so serious-music buyers switched first.

It gave the album a single physical carrier, which helped record companies and artists think in albums.

When a format is limited by a physical constraint, the design that removes the constraint - not the one that pushes more content onto the same grooves - is what changes the market.

The LP became the global standard for full-length albums for about half a century, adopted alongside the 45 for singles. Cassettes, CDs and digital formats eventually displaced it, but the 33⅓ microgroove made the album the unit of music.