Tera de Marez Oyens (1932-1996) became a central figure in modern music, not only as a composer and pianist but also as a passionate advocate for the avant-garde. As a teacher at the Conservatorium of Zwolle, she mentored music students and composers, while also working extensively with young people and amateur musicians, particularly with children’s choirs and school orchestras. In 1998, two years after her passing, her husband Marten Toonder and their children founded the Tera de Marez Oyens Foundation in her honor. To pay tribute to the composer, a composition prize was also established in her name.Ambiversion, a work for tape and bass clarinet, was dedicated to Harry Sparnaay. The term ambiversion refers to a state between extroversion and introversion, offering performers the opportunity to express themselves both outwardly and inwardly, blending with the tape where recordings of bass clarinet and contrabass clarinet are incorporated.