You have to listen to music from way, way back to realize that it really is true that Louis Armstrong is the foundation for all modern jazz and pop. A decent familiarity with popular music before he came along (which I don't intend to denigrate; it can combine intelligence, beauty and great fun, for example Gilbert and Sullivan) helps you hear what Louis' genius gave an astonished world. The sheer virtuosity, the joy, the total personal expression, the combination of irresistible rhythm and emotional truth, and, strikingly, the self-confidence and self-respect.
What a thrill it must have been for a teenager in, say, 1923, whose parents' world of earnest certainty was shattered by the debacle of World War I, who waited and waited for something exciting to happen, feeling that the coming change had to be for the better -- to suddenly hear the latest record at the soda shop, or a party, or a friend's house -- and it was King Oliver's Creole Jazz Band, with young Louis already pushing past his mentor on "Dippermouth Blues." You can't sit still listening to it even now, yet the arrangement -- the improvised arrangement -- is so complex you can listen to it over again. Louis' message to those kids was, "I'm using my brain and heart and talent to make something fine and new right here, right now, and you'll love it! New is good! What we have to say is important!" His message to young musicians was, "Who knows? Maybe you can do it, too! Pick up your horn, Daddy!""
Somebody was listening in Davenport, Iowa, too, and had been for five years since he heard his first jazz -- 20-year-old Bix Beiderbecke, another astonishing voice. From what most sophisticates of the time considered a bland middle-class wilderness arose the golden lyricism of Bix's cornet.
I have never understood those who find Bix's sound sad or melancholy; to me it's always full of joy. Bix might not have known much about making a "success" out of life, but he knew he was good, and he knew what he had to say was his alone. I hear the same joy in his virtuosity as I hear in Louis, and the same confidence that he mattered -- a lot.
As for Bix's influence on Louis, I think I hear it in an interest in opening up the rhythm in a different way, and embracing the lyrical; of course, Louis' genius might have taken him in that direction anyway. But he loved Bix (that's a direct quote -- "I loved that little white boy," he said about Bix), and I don't see that it diminishes Louis in any way to suggest that he, too, could have his ears opened by sonething new to him.