Morton loosened ragtime's rigid rhythmic feeling, decreasing its embellishments and employing a swing feeling. Swing is the most important and enduring African-based rhythmic technique used in jazz. An oft quoted definition of swing by Louis Armstrong is: "if you don't feel it, you'll never know it." "The New Harvard Dictionary of Music" states that swing is: "An intangible rhythmic momentum in jazz...Swing defies analysis; claims to its presence may inspire arguments." The dictionary does nonetheless provide the useful description of triple subdivisions of the beat contrasted with duple subdivisions: swing superimposes six subdivisions of the beat over a basic pulse structure or four subdivisions. This aspect of swing is far more prevalent in African-American music than in Afro-Caribbean music. One aspect of swing, which is heard in more rhythmically complex Diaspora musics, places strokes in-between the triple and duple-pulse "grids".