Free improvisation or free music is improvised music without any rules beyond the logic or inclination of the musician(s) involved. The term can refer to both a technique (employed by any musician in any genre) and as a recognizable genre in its own right.
Free improvisation, as a genre of music, developed in the U.S. and Europe in the mid to late 1960s, largely as an outgrowth of free jazz and modern classical musics. Exponents of free improvised music include saxophonists Evan Parker, Anthony Braxton, Peter Brötzmann, and John Zorn, composer Pauline Oliveros, drummer Christian Lillinger, trombonist George E. Lewis, guitarists Derek Bailey, Henry Kaiser and Fred Frith and the improvising groups Spontaneous Music Ensemble, The Music Improvisation Company, Iskra 1903, The Art Ensemble of Chicago and AMM.
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