Expert pianists' expressive timing consistency: A case study of the Gluck-Sgambati Melody played by Rachmaninoff

In Western art music where performances are based on the composer's score, the degree to which expert musicians tend to be consistent versus spontaneous in their expressive artistic deviations from the score has long been of interest. For example, it is said that the great composer-pianist Sergei Rachmaninoff (1873–1943) exhibited consistency over repeated performances, but quantitative studies are scarce. As he made both acoustic recordings and piano rolls, overlapping repertoire on the different media enables comparison of the same piece over time. Here, we compared his two extant recordings of the Gluck-Sgambati Melody: first in January 1925 (Ampico roll), then 4 months later in May 1925 (RCA audio). Compared with classical renditions of the orchestral version, Rachmaninoff's interpretations are idiosyncratically expressive with ample tempo rubato. In each recording, the time instants of all 112 beats were marked manually. For the piano roll, we used a MIDI file prepared from a scan of the roll followed by model-based processing to correct various sources of error in perforation positions and to account for uniform paper acceleration. Comparison of the inter-beat interval profiles of the roll version and the acoustic recording revealed notable similarities (r = 0.93, mean absolute difference 120 ms) in the ebb-and-flow of expressive timing. The results quantitatively support the notion that Rachmaninoff's expressive timing deviations from the score were remarkably consistent.