Jazz played by a small ensemble featuring collective and solo improvisation. The term is often ascribed especially to the New Orleans pioneers of jazz, although many critics of popular music believe the term better describes the music of a later wave of white Chicago musicians including Jimmy McPartland, Bud Freeman, and Frank Teschemacher. The earliest jazz ensembles grew out of the ragtime and brass bands of New Orleans, incorporating elements of the blues. In early jazz ensembles, such as those led by King Oliver and Jelly Roll Morton, the trumpet or cornet plays the melody, with clarinet and trombone providing accompaniment. The tension created by soloists contrasts with the release of ensemble refrains. It is played with a distinctive two-beat rhythm, resulting in a joyous cacophony at fast tempos or slow, mournful dirges. Dixieland groups usually include banjo, tuba, and drums.