(Program Notes for Sally Pinkas performance, Hopkins Center, Dartmouth College, 2/99, and a few other Boston area concerts)

The Casten Variation (1994) is a computer composed work, for solo piano or any ensemble, based Ruth Crawford's extraordinary Study in Mixed Accents, a pioneering solo piano work from the early 1930's. Asked to do an "analysis" of that work a few years ago, I became interest in, among other things, developing computer- and mathematically-aided visual tools for understanding what I felt was a piece that was on the one hand, unfathomable, and on the other, naturally beautiful. It occurred to me that I might make use of some of the same tools to "resynthesize" the work, retaining much of the work's original form, idea, and aesthetic, but radically altering its length and breadth (and, parenthetically, all the notes).

The technique for this "analysis/resynthesis (a term suggested to me by my colleague Charles Dodge) is one used in psychology to measure perceptual similarity of arbitrary objects ("apples and oranges", known as multi-dimensional scaling. My software, which created The Casten Variation, composes a new set of melodies according to a set of similarity measures derived from the "original." Like the original, it is in five sections, which lengthen toward the middle. Except for the first and last groupings of each section, none of the notes are the same between the analysis (Piano StudyÉ) and the resynthesis (CastenÉ).

Works composed by intelligences other than our own have odd ramifications for performers, but it is important to me that they be written for humans to play. Although my software understands a great deal about certain musical ideas, it has little sympathy for or knowledge about how a performer feels, moves, interprets. In that way it presents a unique challenge for the pianist, and needs a player as gifted and insightful as Sally Pinkas. In playing ...Casten..., Sally needs to construct her own musical logic. As she beautifully pointed out to me, this kind of piece clearly has its own compositional design and integrity, but by its very nature the specifics of that design are not available to us.

The Casten Variation is written in the computer music language HMSL (Hierarchical Music Specification Language), using my own morphological metrics software, and transferred to the program Finale for notational purposes. David Fuqua was of assistance in preparing the notated score. HMSL is written by the composer, Phil Burk and David Rosenboom.

Larry Polansky

February 12, 1999