Mainstream Top 40

Mainstream Top 40 (also called Pop Songs on billboard.com and sometimes referred to as Top 40/CHR) is a 40-song music chart published weekly by Billboard Magazine which ranks the most popular songs being played on a panel of Top 40 radio stations in the United States. The rankings are based on radio airplay detections as measured by Nielsen Broadcast Data Systems (Nielsen BDS). Arbitron refers to the format as contemporary hit radio (CHR).

History

The chart debuted in Billboard Magazine in its issued date October 3, 1992, with the introduction of two Top 40 airplay charts, Mainstream and Rhythm-Crossover. Both Top 40 charts measured "actual monitored airplay" from data compiled by Broadcast Data Systems (BDS). The Top 40/Mainstream chart was compiled from airplay on radio stations playing a wide variety of music, while the Top 40/Rhythm-Crossover chart was made up from airplay on stations playing more dance and R&B music. Both charts were "born of then-new BDS electronic monitoring technology" as a more objective and precise way of measuring airplay on radio stations. This data was also used as the airplay component for Hot 100 tabulations.

Top 40

Top 40 is a music industry shorthand for the currently most-popular songs in a particular genre. When used without qualification it refers to the best-selling or most frequently broadcast popular music. The term is derived from record music charts, a few of which traditionally consist of a total of 40 songs. Top 40 is also an alternative term for the radio format of such music, also known as Contemporary hit radio.

History

The term "Top 40" for a radio format appeared in 1960. The Top 40, whether surveyed by a radio station or a publication, was a list of songs that shared only the common characteristic of being newly released. Its introduction coincided with a transition from the old ten-inch shellac 78 rpm record format for single "pop" recordings to the seven-inch vinyl 45 rpm format, introduced in 1949, which was outselling it by 1954 and soon replaced it completely. The Top 40 thereafter became a survey of the popularity of 45 rpm singles and their airplay on the radio. Some nationally syndicated radio shows, like American Top 40, featured a countdown of the forty highest ranked songs on a particular music or entertainment publication. Although such publications often listed more than 40 charted hits, such as the Billboard Hot 100, time constraints allowed for the airing of only forty songs; hence, the term "top 40" gradually became part of the vernacular associated with popular music.

Contemporary hit radio

Contemporary hit radio (also known as CHR, contemporary hits, hit list, current hits, hit music, top 40, or pop radio) is a radio format that is common in the United States, United Kingdom, Ireland, Canada, New Zealand and Australia that focuses on playing current and recurrent popular music as determined by the top 40 music charts. There are several subcategories, dominantly focusing on rock, pop, or urban music. Used alone, CHR most often refers to the CHR-pop format. The term contemporary hit radio was coined in the early 1980s by Radio & Records magazine to designate top 40 stations which continued to play hits from all musical genres as pop music splintered into adult contemporary, urban contemporary and other formats.

The term "top 40" is also used to refer to the actual list of hit songs, and, by extension, to refer to pop music in general. The term has also been modified to describe top 50; top 30; top 20; top 10; hot 100 (each with its number of songs) and hot hits radio formats, but carrying more or less the same meaning and having the same creative point of origin with Todd Storz as further refined by Gordon McLendon as well as Bill Drake. The format became especially popular in the sixties as radio stations constrained disc jockeys to numbered play lists in the wake of the payola scandal.