Folke Rabe was a Swedish composer and trombonist, born in Stockholm on 28 October 1935 and died there on 25 September 2017. He studied at the Royal College of Music in Stockholm, where his teachers included Karl-Birger Blomdahl, Ingvar Lidholm and György Ligeti, and in the early 1960s he was active as a jazz trombonist before turning to the avant-garde.
His best-known work, What?? (also titled Was??), was produced at the Swedish Radio studios in Stockholm in 1967: a long electronic drone built from layered harmonic tones that slowly breathe and shift, made in the years when he was in contact with Terry Riley, Pauline Oliveros and La Monte Young. Long hard to find, it reached a new generation in 1997 through a reissue on the Dexter’s Cigar label, which added a version at half speed. Other pieces from the period include Bolos for four trombones. From 1980 to 2000 he held senior editorial roles in Swedish public broadcasting.