Jelly Roll Morton in the context of Music of New Orleans

A tone cluster is a musical chord comprising at least three adjacent tones in a scale. Prototypical tone clusters are based on the chromatic scale and are separated by semitones. For instance, three adjacent piano keys (such as C, C♯, and D) struck simultaneously produce a tone cluster. Variants of the tone cluster include chords comprising adjacent tones separated diatonically, pentatonically, or microtonally. On the piano, such clusters often involve the simultaneous striking of neighboring white or black keys.

The early years of the twentieth century saw tone clusters elevated to central roles in pioneering works by ragtime artists Jelly Roll Morton and Scott Joplin. In the 1910s, two classical avant-gardists, composer-pianists Leo Ornstein and Henry Cowell, were recognized as making the first extensive explorations of the tone cluster. During the same period, Charles Ives employed them in several compositions that were not publicly performed until the late 1920s or 1930s, as did Béla Bartók in the latter decade. Since the mid-20th century, they have prominently featured in the work of composers such as Lou Harrison, Giacinto Scelsi, Alfred Schnittke and Karlheinz Stockhausen, and later Eric Whitacre. Tone clusters also play a significant role in the work of free jazz musicians such as Cecil Taylor, Matthew Shipp, and Kevin Kastning.

In tap dancing, jazz, and blues, stop-time is an accompaniment pattern interrupting, or stopping, the normal time and featuring regular accented attacks on the first beat of each or every other measure, alternating with silence or instrumental solos. Stop-time occasionally appears in ragtime music. The characteristics of stop-time are heavy accents, frequent rests, and a stereotyped cadential pattern. Stop-timing may create the impression that the tempo has changed, though it has not, as the soloist continues without accompaniment. Stop-time is common in African-American popular music including R&B, soul music, and led to the development of the break in hip hop.

Stop-time is, according to Samuel A. Floyd Jr., "a musical device in which the forward flow of the music stops, or seems to stop, suspended in a rhythmic unison, while in some cases an improvising instrumentalist or singer continues solo with the forward flow of the meter and tempo. Such stop-time moments are sometimes repeated, creating an illusion of starting and stopping, as, for example, in Scott Joplin's "The Ragtime Dance" and Jelly Roll Morton's "King Porter Stomp"."

James Price Johnson (February 1, 1894 – November 17, 1955) was an American pianist and composer. A pioneer of stride piano, he was one of the most important pianists in the early era of recording, and like Jelly Roll Morton, one of the key figures in the evolution of ragtime into what was eventually called jazz. Johnson was a major influence on Count Basie, Duke Ellington, Art Tatum, Thelonious Monk, and Fats Waller, who was his student.

Johnson composed many hit songs, including the unofficial anthem of the Roaring Twenties, "The Charleston", and he remained the acknowledged king of New York jazz pianists through most of the 1930s. Johnson's artistry, influence on early popular music, and contributions to musical theatre are often overlooked, and as such, he has been referred to by musicologist David Schiff as "The Invisible Pianist."