Ways to ape an ape, drumming

(Oh, right. Blog. Where was I?)

At long last, this summer I finished the first fantasy-transition (Whew!). On to the next section ...

... which (as ever) seems as though it ought to write itself, as the master plan calls for a fairly simple, one-minute duet of the theremin imitating the sounds of a chimpanzee pant-hooting, and the piano imitating the sounds of same chimp drumming on a tree bole with his feet.

A less scrupulous (or simply less obsessive) composer might efficiently transcribe a previous instance of same from an earlier work (because, really, what composer hasn’t already written numerous such passages?). But, no ... I had to come up with something new.

The pant-hooting is easy enough, and offers a new twist in not sticking to octatonic collections (as I’ve usually done before); instead, the zigzag melodies derive directly from the harmonies dictated by the five-voice Ursatz.

The new sticking-point (over the past month or so) has been composing the piano’s “drumming.” The texture has been more or less a given: in the bass register, intermittent staccato dyads (mimicking < left foot, right foot > ). The difficult part (more precisely, the part I made difficult for myself) was finding the right harmonies, to supply enough intervallic variety to maintain interest, but so much as to push the sound across the boundary between “drumming” and “chordal harmony.”

Initially, I tried to map the opening four-note motto {Eb, F, E, F#} onto the five-note chord(s). But transposing the various dyads and triads in each hand led either to monotony (if both hands move in the same direction, by the same intervals) or jarring pitch duplications (if the hands mirrored each other) ... and avoiding pitch duplications led to a tightly limited set of harmonies (so, again, monotony).

The breakthrough (embarrassing, as it seems obvious in hindsight) is that the right kind of monotony can be achieved with surprisingly little effort by

1) committing to a single pitch-class pentad, with various voicings (as in the piano’s accompaniment of the motto at the piece’s start),

2) mapping a five-note extension of the motto onto the Ursatz pentad of the moment ... so, < Eb, F, E, B, Bb > as the soprano

3) partitioning the pentad into the triad < Eb, F, E > and the dyad < Bb, B >,

4) manipulating all of the above isorhythmically, to generate a series of 2 x 3 x 5 = 30 drumming dyads ...

... and given that each talea will comprise four dyads, the series will occur twice (probably spilling into the second, later section of simian mayhem, in which the theremin will also drum, and the piano will also pant-hoot).

Now, it’s just (!) a matter of placing these dyads with unpredictable rests between them, and selecting the appropriate pant-hooting and shrieking gestures from the theremin’s pitch tableaux. Onward ...

Errata (18 Oct 2015): Duh ... forgot to include the 8va indication under the bass clefs on the l.h. staff.