Unexpectedly..................................

Radio began its life as a two-way medium, a practice that continues to this day as ham radio:  individual hobbyists talking to one another over the airwaves, occasionally eavesdropping on other conversations.  But by the early 1920s, the broadcast model that would come to dominate the technology had evolved.  Professional stations began delivering packaged news and entertainment to consumers who listened on radio receivers in their homes.  Almost immediately, something entirely unexpected happened:  the existence of a mass medium for sound unleashed a new kind of music on the United States, a music that had until then belonged almost exclusively to New Orleans, to the river towns of the American South, and to African-American neighborhoods in New York and Chicago.  Almost overnight, radio mad jazz a national phenomenon.  Musicians such as Duke Ellington and Louis Armstrong became household names.  Ellington's band performed weekly national broadcasts from the Cotton Club in Harlem starting in the late 1920s;  Armstrong became the first African-American to host his own national radio show shortly thereafter.
     All of this horrified Lee De Forest, who wrote a characteristically baroque denunciation to the National Association of Broadcasters:  "What have you done with my child, the radio broadcast?  You have debased this child, dressed him in rags of ragtime, tatters of jive and boogie-woogie."  In fact, the technology that De Forest had helped invent was intrinsically better suited to jazz that it was to classical performances.  Jazz punched through the compressed, tinny sound of early AM radio speakers;  the vast dynamic range of a symphony was largely lost in translation.  The blasts of Satchmo's trumpet played better on the radio than the subtleties of Shubert.
     The collision of jazz and radio created, in effect, the first surge of a series of cultural waves that would wash over twentieth-century society.  A new sound that had been slowly incubating in some smalls section of the world - New Orleans, in the case of jazz - finds its way onto the mass medium of radio, offending the grown-ups and electrifying the kids.

-Steven Johnson,  How We Got to Now:  Six Innovations That Made the Modern World