Structure and Performance Timing in Bach's C Major Prelude (WTCI): An Empirical Study

There are not many things about which most music analysts will agree; but one of them is that there should be a close relationship between the analysis of music and its performance. Edward T. Cone's (1962:36) statement on this subject is perhaps the most frequently quoted: 'an analysis', he said, 'is a direction for a performance'. But it makes equally good sense to reverse Cone's formulation and say that a performance is a direction for an analysis; indeed Cone himself implies as much when he goes on to say, speaking of the relationships between events in a composition, that 'the job of analysis is to uncover them explicitly, but they are implicitly revealed in every good performance'. The trouble is that we have little in the way of a rigorous methodology for extrapolating from a performance the analytical judgments, or misjudgments, that are embodied in it even in the case of rhythm, where (particularly in keyboard music) the performer's power to make or mar a piece is at its height. Nearly twenty-five years ago Peter Westergaard (1972:229) catalogued the customary failures of rhythmic theory, and went on to suggest that these failuies 'might be remedied by a study of rhythmic detail which, instead of assuming the bar lines of the printed page, examines the interplay of notated compositional elements with the unnotated means the performer uses to project accent placement . . . . Exact information about just what the performer does at lower levels could provide valuable clues to what the composer does on higher levels.' This essay is a belated response to Westergaard's suggestion. There are several reasons why the C major Prelude from WTC I makes a good focus for such work. It is the subject of one of Schenker's (1969) best-known studies and the classic illustration of obligatory register; but even more to the point is its virtually complete lack of rhythmic differentiation at foreground level. The printed page shows a steady and uninterrupted series of attacks; any systematic variation in durations which the performer may introduce must therefore derive from higher-level compositional structure there is nowhere else it can come from. In consequence, the C major Prelude makes it possible to study the effect of higher-level structure upon rhythmic nuance without getting bogged down in the complexities of how performers project foreground