Prozession (Procession), for tamtam, viola, electronium, piano, microphones, filters, and potentiometers (six performers), is a composition by Karlheinz Stockhausen, written in 1967.
[3] and was written for and dedicated to the ensemble with which Stockhausen was regularly touring at that time: Alfred Alings and Rolf Gehlhaar (tamtam with hand-held microphone), Johannes Fritsch (viola), Harald Bojé [de] (electronium), and Aloys Kontarsky (piano).
[5] In addition to recordings, over the scourse of three years this same ensemble performed Prozession approximately twenty-eight times.
It is up to the performer to decide which of these dimensions is to be affected, except that vertically stacked signs must be applied to different parameters.
[9] Despite this indeterminacy, a large number of plus signs (for example) will result in successive events becoming longer, more finely subdivided, louder, and either higher or wider in range; a large number of minus signs will produce the reverse effect.