The so-called “blue notes” are what give the blues its distinctive sound, says Larry Dwyer, Notre Dame associate professional specialist of music and director of jazz studies. Blue notes are “bent” to a slightly lower pitch than those in the traditional European scale. They trace their origin to the original scales on which native African songs are based.
In terms of structure, Dwyer says blues songs typically follow a 12-measure form and, like gospel music, often incorporate call-and-response between the singer and the audience.
“Like all good music it expresses something in the human heart that has an emotional effect on the listener,” Dwyer says.