This article presents the results of a series of interviews that focussed on real-time, MIDI-based performance systems; it traces the ideas behind the real-time performance systems of Max Matthews, Barry Vercoe and Roger Dannenberg. These system designers discusses their approaches to the meaning of “ensemble”, synchronisation, and expressive timing. They offer their solutions to the goal of freeing the soloist from the historic role of accompanist of computer-generated tapes.