The Kinematic Rubato Model as a Means of Studying Final Ritards Across Pieces and Pianists.

This paper presents an empirical study of the performance of final ritards in classical piano music by a collection of famous pianists. The particular approach taken here uses Friberg and Sundberg’s kinematic rubato model in order to characterize the variability of performed ritards across pieces and pianists. The variability is studied in terms of the model parameters controlling the depth and curvature of the ritard, after the model has been fitted to the data. Apart from finding a strong positive correlation of both parameters, we derive curvature values from the current data set that are substantially higher than curvature values deemed appropriate in previous studies. Although the model is too simple to capture all meaningful fluctuations in tempo, its parameters seem to be musically relevant, since performances of the same piece tend to be strongly concentrated in the parameter space. Unsurprisingly, the model parameters are generally not discriminative for pianist identity. Still, in some cases systematic differences between pianists are observed between pianists.