The unmeasured prelude is perhaps the perfect example of the necessary back-and-forth between continuity and discretization, since it is written down, to be sure, but rhythmically unfixed. Musicians agree on certain conventions – for example a succession of adjacent notes form a triad – but its sole construction would connect it to the improvised nature of what will later lead to the rhapsody. Indeed, the unmeasured prelude leaves some latitude to the musician’s freedom in the field of interpretation. However, without analysis, there is no possibility for a musical work. The prelude’s unity depends on its components, their function and their articulation. The analysis is used to give a direction to the prelude’s realization. Thus, a structure of the score appears and gives birth to the work.
The unmeasured harpsichord prelude in France in the 17th and 18th centuries does neither correspond to a form, nor to a specific structure. It is polymorphic. None are identical to each other. A quick glance suggests a stratification that seems at first to affect its construction. A more careful reading will also reveal harmonic stratification. Thus, the unmeasured prelude presents itself to us as a complete composition, albeit one that reveals itself only after having been studied.
This layered structure can be analyzed on three levels: macroscopic, median and microscopic. The first corresponds to the entire piece, the second to the cells, and the third to the unities composing the different cells. Moreover, does a specific notion of tension-relaxation exist for the unmeasured prelude? Is the analytical approach of an unmeasured prelude valid for every one? And more generally, can this study on discretization and continuity in an unmeasured prelude give rise to a reflection on the analysis of other musical works of other periods?