Si suona Passacaglio. A Didactic Introduction to Improvisation in the Italian Practice of Basso Ostinato
Nicola Cumer · Università degli Studi di Pavia · 2012
As Spiridionis shows in his Nova instructio (1670-77,) the Excellentissimus Componista (the most excellent composer) must be able to combine by improvising different harmonic and melodic models, building up a musical form. These models can be found in the works of the great masters. They must be analyzed for finding out the basic elements and then systematized. This process can be outlined best by ostinato forms, as the bergamasca and the passacaglio. In the preliminary exercises the three voices of the basic harmonization of the passacaglio are at first exchanged, then diminuted and enriched with chromaticism. The anonymous pieces in the manuscript Chigi Q IV 27 are a sort of intermediate level, between the basic exercises and the highest level in the art of passacaglio, the Cento partite sopra passacagli by Frescobaldi. There one can find every way of voice leading, dissonances, modulations, blue notes, changes in proportions and affect shifts.