The Sound of (iN)stability: Making Subtle Movement Fluctuations Perceptible via Material Metaphor Sonification in Ballet

Movement inherently involves (in)stability, forming a continuous feedback loop where perception, via internal sensations and external cues, guides adjustment. In ballet, recognizing and managing subtle transitions into and out of instability is key for control and fluidity. However, these micro-instabilities often elude conventional feedback. We introduce the Sound of (iN)stability Awareness (SONA), an interactive sonification interface co-designed with ballet dancers to render micro-instabilities perceptible through metaphor-based sound. SONA maps movement data from the elbows to evolving auditory textures inspired by natural transformations. A threshold-based algorithm detects user-specific disruptions in motion continuity and sonifies them via adaptive feedback. In a within-subjects study with 24 dancers, SONA improved access to instability, enhanced user experience, and reduced event frequency and duration. Participants described the sounds as intuitive and meaningful, reporting greater bodily awareness. Our findings highlight metaphorical sonification as a promising approach for making movement qualities perceptible, supporting sensorimotor reflection in movement-based training.