‘Smooth Jazz Radio’ began in the 1980’s as “adult alternative”, a well-defined radio format, with jazz, new-age music and adult contemporary music. In the 1990s, the format became much more jazz-oriented, with very little new-age, and emphasizing young artists

It was a popular radio format that included songs by artists such as George Benson, Pat Metheny, Kenny G, Luther Vandross, Sade, Robin Thicke, Anita Baker, Basia, Dave Koz and Chuck Mangione..

Beginnings:

Smooth jazz as a radio format has its roots in the construction of what were once called “beautiful music” stations, which generally played fifteen-minute sets consisting of instrumentals bookending a vocal song or two. The incubators of the format were specialty shows at night or on the weekends, in places such as Atlanta (WQXI-FM and WVEE-FM), Miami (WWWL-FM) and San Antonio (KTFM). 

The first jazz radio station to attempt to reach an audience beyond hardcore jazz fans full-time was New York’s WRVR-FM, which was acquired by Sonderling Broadcasting in 1976. 

In 1983, “adult alternative” became a well-defined radio format, with jazz, new-age music and adult contemporary music. In 1987, the switch by album-oriented rock KMET in Los Angeles to KTWV “The Wave” made the format more popular.

In the late 1980s, the format adopted the name “Smooth Jazz” replacing the old slogan “Music for a New Age” as the station added more vocals and dropped most “avant-garde” instrumentals. They widely syndicated “The Jazz Show with David Sanborn” and his association with saxophonist Dave Koz. 

Evolution:

Over a six-year period ending in 1993, the format increased its audience by 140 percent, and from 1992 to 1993, by 67 percent. Listeners were 71 percent white and 28 percent black. Advertisers recognized that adult alternative music tended to attract buyers of upscale items. The format became much more jazz-oriented, with very little new-age, and even while emphasizing young artists, the format kept its heritage acts as well. However, smooth jazz did add artists from adult contemporary music to increase its popularity with a larger audience; artists included Mariah Carey, Bonnie Raitt, Sting, Bruce Springsteen, Paul Simon, Michael Bolton, Tina Turner, and Janet Jackson.

The smooth jazz music mix included 70 percent instrumentals and 30 percent vocals. Programmers no longer regarded the music as merely “background”. In 1994, Smooth Jazz experienced the largest increase in the relationship between audience share and advertising revenue. Although the format was increasing in popularity,

Smooth Jazz has gone on to be recognized as a successful radio format, first emerging in name in the mid- to late-1980s and subsequently spreading into most radio markets within the United States as well as to other countries.

Today:

Around 2007, the format became less popular it was abandoned by several high-profile radio stations across the United States., including WQCD (now WFAN-FM) in New York, WNUA Chicago (now WEBG), WJJZ in Philadelphia (now WISX), and KKSF (now KOSF) in San Francisco. 

Programmers say the audience for the format has aged beyond the prime demographic sought by advertisers. Despite the format’s demise outside a handful of commercial radio outlets, a number of non-commercial and HD stations have taken up the music. It is still available on SiriusXM on Channel 66, known as “Watercolors” and on the Music Choice cable radio service. In addition, Smooth Jazz concerts, recording sales, as well as increased Smooth Jazz offerings on the Internet, continue to show strong fan support for the genre

Source: Wikipedia