Making sound with numbers, six years later

In the first edition of the DAFx Conferences an extensive tutorial on professional and research software devoted to sound and music making was presented. The present paper attempts a revision of the concepts expressed in that tutorial, focusing particularly to the aspects related to research and innovation fostered by a strong paradigm shift that has happened in the mean time: that of Free Software development. Of course, this paradigm shift has also had its difficulties and harsh spots, requiring many extra efforts in order to overcome them. This paper will try to describe these as well as to outline the current state-of-the-art in the field.