Sonification is the use of non-speech audio to convey information. We are developing tools for interactive data exploration, which make use of sonification for data presentation. In this paper, model-based sonification is presented as a concept to design auditory displays. Two designs are described: (1) particle trajectories in a "data potential" is a sonification model to reveal information about the clustering of vectorial data and (2) "data-sonograms" is a sonification for data from a classification problem to reveal information about the mixing of distinct classes.