The Belgian vocal ensemble Graindelavoix is fascinated by the voice and the psychological effects of early vocal music. For them, the focus is not on a uniform, harmonious sound; rather, the singers are encouraged to express their subjective emotional experiences through their own unique vocal timbres. For our festival, they have developed the program “Per Monstra ad Astra.” From the Middle Ages to the late Renaissance, from Guillaume de Machaut to Carlo Gesualdo, the eight singers, under the direction of Björn Schmelzer, explore the ancient idea of the harmony of the spheres and demonstrate how, from very early on, music and the cosmos were connected not only through harmony, but also through irrationality, infinite variation, and expressive chromaticism.