This project extends the work previously carried out within the .Music & Hacking. project. It aims at analyzing the multiple material transformations, adjunctions or inventions that musicians exert on their instruments, considered as means of artistic singularization, ergonomic optimization, institutional circulation or cognitive extension. Nearly fifty filmed interviews were conducted with instrumentalists with varied improvisational practices (free improvisation, jazz, baroque music, traditional music). Every musician was interviewed in their workshop, instrument .in hand., to allow the finest possible exploration of their lutherie practices. This work will lead to the writing of a book, and will be accompanied by the realization of a web-documentary.