The big bands get smaller and grittier.
In 1949, Billboard changes the name of its "Race Records" category to "Rhythm and Blues Records." Although the name changed, the meaning didn't. Rhythm & blues was music made by Black musicians for Black listeners.
Many, if not most, early rhythm & blues performers came out of the big band swing era. In addition to jazz, rhythm & blues was influenced by blues and gospel music, but it evolved into its own unique style in the post-World War II era combining soulful singing and a powerful backbeat. In fact, the birth of rhythm & blues was the death knell for the big bands. The blues singer Gatemouth Moore said of Louis Jordan, "He was playing...with five pieces. That ruined the big bands ... He could play just as good and just as loud with five as 17. And it was cheaper." (Quote from The Chitlin' Circuit and the Road to Rock 'n' Roll, Preston Lauterbach, 2011)
Hey everybody, let's have some fun
You only live but once, and when you're dead you're done
So let the good times roll, let the good times roll
Don't care if you're young or old, get together let the good times roll
Let The Good Times Roll by Louis Jordan
See the girl with the diamond ring
She knows how to shake that thing
All right now now now, hey hey, hey hey
What'd I Say by Ray Charles