This research is concerned with issues of privacy, awareness and the emergence of roles in the process of digitallymediated collaborative music making. Specifically we areinterested in how providing collaborators with varying degrees of privacy and awareness of one another influencesthe group interaction. A study is presented whereby ninegroups of co-located musicians compose music together using three different interface designs. We use qualitative andquantitative data to study and characterise the musician’sinteraction with each other and the software. We show thatwhen made available to them, participants make extensiveuse of a private working area to develop musical contributions before they are introduced to the group. We also arguethat our awareness mechanisms change the perceived quality of the musical interaction, but have no impact on theway musicians interact with the software. We then reflecton implications for the design of new collaborative musicmaking tools which exploit the potential of digital technologies, while at the same time support creative musicalinteraction.