Four sound researchers, four horns: Gletsjer⁴ forms an ensemble that is both unusual and visionary. Elena Kakaliagou, Morris Kliphuis, Abigail Sanders, and Samuel Stoll are internationally active musicians working at the intersection of Neue Musik, improvisation and sound experimentation. They meet in an acoustic adventure: the chapel in Bethanien itself becomes a participant, the horn unfolds its full spectrum in the space and is lost in its reverb. In their fascinating monochrome instrumentation, the quartet presents works by Pauline Oliveros, Petr Bakla (WP), Jennifer Walshe, and Max Murray (WP).