Repertoire-Centred Design: Mechanical Augmentations in Digital Lutherie for Acoustic Musical Instruments

Over the last century, the practice of musical instruments modification has evolved in a wide range of contexts, from early avant-garde to contemporary digital practices. More recently, research has expanded this field through instrument modifications grounded either in artistic exploration or in user-centered design, often targeting the needs of specific groups of musicians.In this paper, we present a series of mechanical augmentations for traditional instruments - theorbo, accordion, bass clarinet, and euphonium - developed using digital fabrication techniques. Drawing on second-wave HCI's focus on workplaces, we frame musicians as workers and focus on the idiosyncratic needs of specific repertoire (i.e., baroque or post-avantgarde written music). We introduce the concept of repertoire-centered design as a way to ground instrument augmentation in concrete practices and constraints of specific musical works.After presenting the idea, design, and implementation of our augmentations, we discuss how our approach situates the design process within the broader ecology of musicians' working practices, supporting long term adoption in a real-world performance context.