David Rosenboom’s Zones of Influence, composed in 1984-1985, is a five-part work for solo percussion and computer generated compositional algorithms. The composition, which is significant for the innovative way in which it connected acoustic instruments with real-time processing, was written for percussionist William Winant, who performs it here.
Although the work was written as a solo for Winant, in a sense it serves as a feature for a second performer as well. This “performer” is the Touché computer assisted digital instrument, a keyboard designed by Rosenboom and Donald Buchla at a time when MIDI technology being developed but had not yet come into wide use. With Touché, Rosenboom was able to combine Winant’s varied array of pitched and unpitched percussion instruments with live processing in a way that was groundbreaking at the time and still is provocative today. Happily, Pogus has issued the complete work, the first time ever on a recording.
Touché’s role in shaping the overall texture of the work is immediately apparent in the way it supplements the instruments’ timbral qualities. Like many processing interfaces, Touché creates novel timbres, some of which conserve something of the acoustic instruments’ sound characteristics and some of which appear quite alien. Overall there is a tendency toward timbres of a sleek-surfaced, metallic cast—sometimes sounding as if they were produced by a hypertrophied toy piano–which contrast markedly with the sounds of Winant’s wood and membrane instruments. Particularly dramatic examples of this contrast can be found in Winding of a Spring Tripartite Structure for three snare drums, and Closed Attracting Trajectories Melody Set 2, for marimba and xylophone.
Beyond the surface stratum of sounds, the electronics’ interventions alter Winant’s performances at the compositional level. Rosenboom takes patterns of tones or sounds produced by the performer and processes them with real time compositional algorithms. A good example of this is in Zones’ final section, where a set of arpeggios and glissandi on violin—played by Rosenboom, as it happens—is subjected to accelerating changes. By using recombinatory operations the program alters the violin’s pitches, phrasing and tempos, sometimes quite dramatically. The traditional value of thematic development is abstracted and augmented by a multiplication of contrapuntal lines, leading to a densely complex surface sound. Extended to the work as a whole, Rosenboom’s compositional processing makes for an especially dynamic structure built up of proliferating and interpenetrating lines.
Also included in this two-disc set is Study for Zones, a kind of prototype work in which Rosenboom experimented with early versions of the algorithms that would go into the making of the final work.