  In this paper we present a preliminary version of the ACCompanion, an
expressive accompaniment system for MIDI input. The system uses a probabilistic
monophonic score follower to track the position of the soloist in the score,
and a linear Gaussian model to compute tempo updates. The expressiveness of the
system is powered by the Basis-Mixer, a state-of-the-art computational model of
expressive music performance. The system allows for expressive dynamics, timing
and articulation.
