Investigations of Between-Hand Synchronization in Magaloff’s Chopin

This article presents research towards automated computational analysis of large corpora of music performance data. In particular, we focus on between-hand asynchronies in piano performances—an expressive device in which the performer’s timing deviates from the nominally synchronized timing of the score. Between-hand asynchronies play an important role, particularly in Romantic music, but they have not been assessed quantitatively in any substantial way. We give a first report on a computational approach to analyzing a unique corpus of historic performance data: basically the complete works of Chopin, performed by the Russian-Georgian pianist Nikita Magaloff. Corpora of that size—hundreds of thousands of played notes with substantial expressive (and other) deviations from the written score—require a level of automation of analysis that has not been attained so far. We describe the required processing steps, from converting scanned scores into symbolic notation, to score-performance matching, definition, and automatic measurement of between-hand asynchronies, and a computational visualization tool for exploring and understanding the extracted information.

Temporal asynchronies between the members of musical ensembles have been found to exhibit specific regularities: The principal instruments in classical wind and string trios tend to be 30–50 msec ahead of the others (Rasch 1979); soloists in jazz ensembles show systematic temporal offsets relative to the rhythm group (Friberg and Sundström 2002). As the two hands of a pianist are capable of producing different musical parts independently (Shaffer 1984), differences in the timing organization may be utilized as a means for artistic expression. Typically such asynchronies include bass anticipations, where the bass tone precedes the other notes by 70 msec or more (Vernon 1936; Goebl 2001) or sequences of right-hand lags in jazz piano solos, where the soloist delays the onsets of a series of notes relative to the beat (played, e.g., by the left-hand chords, bass, and drums) only to come back into time again (e.g., found in Red Top in the Erroll Garner Trio album Concert of the Sea from 1955). A similar effect is documented for the Classical–Romantic piano repertoire, where particularly Chopin recommends the right hand to take as much temporal freedom as desired, while the left hand is instructed to keep—like a conductor—a strict timing (“tempo rubato in the earlier meaning,” Hudson 1994). Furthermore, the melody voice in expressive piano performance (the most salient voice, usually the highest-pitched part) has been found to occur around 30 msec earlier than the tones of the other voices (melody lead, Palmer 1996); this effect, however, is associated with differences in the loudness of the tones and is best explained as an artifact of the different key and hammer velocities (Repp 1996; Goebl 2001). In particular, melody lead within the same hand is caused by velocity differences; the within-hand asynchronies are also usually smaller than those found between the hands (Repp 1996; Goebl 2001).

Thus, asynchronies in piano performance contain a wealth of potentially expressive features and at the same time reflect quite subtle effects such as melody lead. This article seeks to investigate particularly the more expressive aspects of the between-hand asynchronies, such as bass anticipations and regions of tempo rubato in the earlier meaning. We present preliminary results on the between-hand asynchronies in Magaloff’s Chopin to demonstrate the variety of insights that such large corpora can offer. Toward the end of the article, we attempt to model these asynchronies on the basis of mostly local score features. Finally, we discuss the future pathways of this research endeavor and its potential for computational modeling and musicological investigation.

The Chopin Corpus

The analyzed Chopin corpus comprises live concert performances by the Georgian-Russian pianist Nikita Magaloff (1912–1992), who played almost the entire solo repertoire of Chopin in a series of six recitals between January and May 1989 at the Mozart-Saal of the Wiener Konzerthaus in Vienna, Austria. This concert hall provides about 700 seats (www.konzerthaus.at) and ranks among the most distinguished halls in Vienna. In this unprecedented project, Magaloff, by that time already...