Black activism among musicians of the 1960s:
 Expression of black consciousness, African themes, spirituality
 Formation of musicians' collectives to control economics of jazz production
  AACM: Association for the Advancement of Creative Musicians
  BAG: Black Artists Group

Features common in Avant-Garde or Free Jazz:
Form:
freer formal structures (beyond 12-bar and 32-bar forms)
absence of pre-determined harmonic structure
Improvisation:
collective and solo; "outside playing"; indeterminate pitches
Timbre:
hard-edged sound; wide range of instrument, extended sounds
including voice-like sounds such as shrieks and wails
Instruments:
absence of harmonic support instruments such as piano or guitar
unconventional instruments (for jazz)
Rhythm:
absence of steady pulse or meter
Rhythm section:
altered role in which bassists and drummers are no longer timekeepers

Musicians:
John Coltrane
Eric Dolphy
Ornette Coleman
Archie Shepp
Albert Ayler
Cecil Taylor
Muhal Richard Abrams (AACM)
Art Ensemble of Chicago
Anthony Braxton
World Saxophone Quartet (Black Artists Group)
Sun Ra