With The Vocal Chorder, a large interactive instrument to create accompaniment, opera singers can get more power over the performance. The device allows performers to interactively accompany themselves through pushing, leaning on and bending steel wires. The design was guided by the unique needs of the solo-singer, explored through autobiographical design and material explorations, some on stage, and later tested by other singers. We discuss how designing for opera and for the stage requires extraordinary durability and how opera performances can change with a bodily-oriented instrument such as The Vocal Chorder. Through a designerly exploration, we arrived at a device that offered (1) a tool for singers to take control over the rhythmical pace and overall artistic and aesthetic outcome of their performances, (2) an enriched sense of embodiment between their voice and the overall performance; and (3) a means to empower opera singers on stage.