In 1924, Louis Armstrong joined the Fletcher Henderson dance band for a year, as featured soloist. The original New Orleans style was polyphonic, with theme variation and simultaneous collective improvisation. Armstrong was a master of his hometown style, but by the time he joined Henderson's band, he was already a trailblazer in a new phase of jazz, with its emphasis on arrangements and soloists. Armstrong's solos went well beyond the theme-improvisation concept and extemporized on chords, rather than melodies. According to Schuller, by comparison, the solos by Armstrong's bandmates (including a young Coleman Hawkins), sounded "stiff, stodgy," with "jerky rhythms and a grey undistinguished tone quality." The following example shows a short excerpt of the straight melody of "Mandy, Make Up Your Mind" by George W. Meyer and Arthur Johnston (top), compared with Armstrong's solo improvisations (below) (recorded 1924). Armstrong's solos were a significant factor in making jazz a true 20th-century language. After leaving Henderson's group, Armstrong formed his Hot Five band, where he popularized scat singing.