Why top "40" ?

December 8, 2006 9:40 AM

America's Top 40 is an institution, since the 1970s. The UK had it's top music charts, but around 1971 lists of 40 songs seemed to become popular. I know the 40 are a subset of Billboard's 100, but why 40? Why did 40 become more popular than 75, 50, 20 or 12?
posted by Mozai to Media & Arts (5 answers total)

From this about.com link:

"In the early 1950's a new approach to programming music on the radio began. There are conflicting stories about the actual invention of top 40 radio, but it is clear that the idea for top 40 emerged out of awareness of music played on jukeboxes.

The standard jukebox of the time held 40 singles. The pioneers of top 40 noted that these records were played in rotation by customers with the most popular songs sometimes played many times a day. Radio pioneers Todd Storz, Bill Stewart, and Gordon McLendon all contributed to the development of a radio format that consisted of a local disc jockey playing the current hit records interspersed with news and promotion of the local station. Within a few years the top 40 format spread across the U.S."

Sounds plausible to me, I guess.
posted by slenderloris at 9:45 AM on December 8, 2006

I don't know, but I would guess that it had something to do with the constraints of some medium. It might be the number of songs + associated metadata that could be printed in one column of a tabloid-sized sheet of paper. It could be the number of songs that could be played comfortably in a 4 hour block (with plenty of ads). I could be the maximum number of songs a radio station could overemphasize in their rotation and still cause a noticible impact on record sales while still having some room for old favorites and introducing some new music.
posted by Good Brain at 9:48 AM on December 8, 2006

I remember hearing once that 40 songs at 3 min/per (120 min) plus commercials and basic DJ time worked out to a 3 hour playlist, which was considered a good amount of time for no repetition of content.
posted by tdischino at 10:11 AM on December 8, 2006

If it was a strict list of most requested/played towards the least, then the 40 cut-off could be for a number of reasons.

If it was based on a ranking of the number of requests/plays and there was a natural drop off at around the 40 mark, it might also make sense. So you would have plays in the numbers around 100 for song 39, 40, perhaps 41, but then it drops to 10 for 42. Thus, "Top 40" represented the bulk of what people were listening to.

Just a guess.

I say "requested/played" as I have no idea for the basis of how they ranked them.
posted by qwip at 12:53 PM on December 8, 2006

This may be apocryphal, but we engineers who were around in the 60's remember that that 1 Top 40 cycle (3 hours) was the exact length of the workday for program managers.
posted by paulsc at 7:20 PM on December 8, 2006