Medieval methods to visualize sound developed in dialogue with geometrical, arithmetical, cosmological, grammatical, philosophical, logical, and theological knowledge. Located between the sensory and the imaginative, the quadrivium of musica, geometry, arithmetic, and cosmology was nonetheless grounded in the realm of the visual. Visualizations of the harmony of the spheres, the harmony of the human body, and bodily perceived sounds appear in manuscripts as diagrams, graphs, and line drawings using parchment, ink, and pigments. The talk focuses on two circular medieval diagrams from the 9th and 10th centuries. Close analysis of the diagrams and their codices will demonstrate how medieval scribes and scholars created new shapes and forms on parchment to move between dimensions.