Abstract
Eclipse is a one-movement work that is approximately twenty minutes in duration. It is written for orchestra and microcomputer-synthesized tape. In the work the composer explores the two possibilities of (1) making use of a microcomputer to produce imitative timbres that closely approximate acoustic instrument sounds, and (2) combining an orchestra and tape in exacting and specific synchronization.Eclipse consists of three sections. The first is introductory in nature and introduces the two interval series upon which the work is based. Several subdivisions of the second section are devoted to presentation of planetary melodies calculated and notated in the treatise Harmonies of the World published by Johannes Kepler in 1619. Further transformation of the interval series is carried out in the middle section. The third section carries on the transformation of motives derived from the two interval series and concludes the work.The two freely atonal interval series are not used in a strict serial manner. Pitch motives are derived from each series and recombined in free counterpoint. They generally retain the basic interval structure with which they first appear. No individual rhythm emerges as being predominantly related to either series. At each appearance of either series the rhythms are generally different.The tape part appears only in the middle section of the work. The music delegated to the tape is given a critical role in the progress of the music. Harmonic structures appearing in the tape as well as the orchestra include (1) chromatic chords, (2) vertical structures resulting from the combination of free contrapuntal lines, and (3) chords built in thirds (tertian harmonies).Eclipse is significant in the development of the composer for it continues his interest in the production of more lyric melodic structure. It appears, after a review of research reported in Dissertation Abstracts, Dissertation Abstracts International, and the Schwann Catalog, that Eclipse is among the first works to combine imitative, acoustic instrument-like timbres generated on a microcomputer system in specific, pre-determined synchronization with orchestra.