Back in the good ol' days, radio stations played records (remember those?). In the early 60s, AM radio was primarily middle-of-the-road vocals and FM was mostly instrumental background music or a simulcast (duplicate) of its sister AM station.

By the mid-60s, many AM radio stations had switched to rock formats, such as "Boss Radio," due to the influence and "guidance" of newly-bred and successful consultants like Bill Drake. Meanwhile, FM stations remained very much in the background. In fact, they were so much in the background that many began to play "background" music on large automation machines that relied on reel-to-reel tape decks to play the music. The companies that made these machines also produced the tapes that were played on them--Schaeffer, IGM (International Good Music), etc.

Later, as FM receiver penetration in cars and homes grew, broadcasters became more interested in programming FM stations as standalone profit centers. In the mid-70s, syndicated radio formats became an entity themselves, and many companies were formed that specialized in producing very sophisticated programs for these automation systems.

The original formats were beautiful music, but later virtually every format was offered. From a technical perspective, two types of programming were available. One was known as "matched flow" where the programmer would deftly put together a "music sweep" of four or more songs to fill a quarter hour time slot, and where the songs were carefully chosen to segue (transition) together well. The downside to this type of programming was that after the tapes were played a few times, listeners memorized the segues and could predict the next song.

The other type of programming was known as "random select" where each tape played only one musical selection or song and a subsonic (low frequency) tone at the end of the selection would trigger the next event, that event being the next song. This would continue with four or five tapes intermixing until the time clock of the system over-rode the music in order to insert a commercial break. The predictability of matched flow was avoided in this type of programming, but some "unfortunate" segues sometimes happened when a clash of musical styles occurred or when the tapes were improperly recorded so that one song would "step on" (play on top of) the one preceding it.

When the beautiful music formats started, there was a large amount of material from which to choose. Gradually, though, the American record companies released fewer and fewer instrumental albums. This forced the program companies (syndicators) to look overseas for music, and they discovered a treasure trove of fresh recordings in England, France, Spain, Japan and other countries. These recordings, interspersed between the American "standards" made up much of what was heard on the stations throughout the later 70s.

Some of the more well-known program syndicators that recorded these formats included: