Free jazz
Free jazz was an important influence in the American post-hardcore scene of the early 90s. Drive Like Jehu took Black Flag's atonal solos a step further with their dual guitar attack. The Nation of Ulysses had Ian Svenonious alternating between vocals and trumpet, and their complex song structures, odd time signatures, and frenetic live shows were as much hardcore punk as they were free jazz. They even did a brief cover of John Coltrane's "A Love Supreme" on their "Plays Pretty for Baby" album, though they titled it "The Sound of Jazz to Come" after Ornette Coleman's classic album "The Shape of Jazz to Come". Chicago's Cap'n Jazz also borrowed free jazz's odd time signatures and guitar melodies, marrying them with hardcore screams and amateur tuba playing. The Swedish band Refused was influenced by this scene and recorded an album titled "The Shape of Punk to Come", where they alternate between manic hardcore punk numbers and slower, jazzy songs.