Classic jazz is derived from ragtime where a syncopated beat is important to the music. Hot jazz takes this style of music one step further. Where jazz tends to have a calmer melodic line, hot jazz progresses the melody with energy and sound. Both forms of music allow individual musicians to embellish the melody. The difference is that classic jazz is complete within the melody while hot jazz builds it to a climax.
Both classic and hot jazz are musical forms that embrace improvisation of the different instrumentalists. Hot jazz builds to a crescendo in the melodic line at the end of the performance. Each piece begins its journey as a classic jazz melody. As each musician has their solo, the music builds to a crescendo. By the time the finale is reached, the music has progressed in tempo and sound production. This style of jazz has been popular with large and small bands. It represents a more energetic outlet for jazz musicians and their audiences.