Following a period of studies at the Hochschule für Musik und Theater München and in courses given by Hermann Scherchen in Gravesano, Riedl, influenced by Carl Orff und Edgar Varèse, devoted himself as a composer particularly to percussion and Lautgedichte (sound poetry) (Schmidt 2001).
It was led by Werner Nussbaumer, a physician from Gravesano, former member of the Greens and known for his actions aimed at promoting Cannabis indica for therapeutical purposes.
In other studios, such as Milan, Rome, Eindhoven, Brussels, Gravesano, and New York, experiments with musical structures and technical innovations were also ongoing.