Clusters (review)

Hubert Howe is a well-known pioneer and researcher in computer music, and a champion of Barry Vercoe's open source program Csound. Howe's career, spanning 50 years, is chockfull of cutting-edge work that often uses novel approaches to tuning, timbre, and harmonic materials. The compositions on Clusters, composed between 2005 and 2011, push these envelopes with precision, reflecting the composer's ongoing interest in "creating interesting, unusual, and intricately structured sounds." In the liner notes, the composer coherently explains both the aesthetic and technical elements and motivations for each of the seven pieces on this CD. As expected, all seven works were created using Csound.

In the first piece, Clusters (2010), Howe uses five-note chords containing inharmonic components, which the composer describes as "harmony becoming spectrum." This is an intriguing strategy, and, of course, one that is a distinguishing characteristic of the spectral school. The primary sonic material for this first piece comes from a basic additive synthesis process, but Howe includes four additional Csound instruments for timbral enhancement. There is also a strong sense of spatialization, defined largely by frequency sweeps tethered to panning effects. About a third of the way into the piece the texture becomes sparser, with thinner, more delicate clusters in the higher registers. Gradually, more dissonant, lower-register clusters are added for balance. Throughout the piece, envelopes seem to die away prematurely. This contributes to a sense of uneasiness and flux, but also symmetrically mirrors the same approach found in many of the attacks. Toward the end of the piece, Howe uses a perpetual glissando effect not unlike the aural illusion known as Shepard tones. The composition's final sound is abruptly cut off, as if a buffer simply ran out of space.

Inharmonic Fantasy No. 2 (2007) presents fused timbres that are more variegated than the first work. Howe carefully controls his inharmonic partials with respect to rhythm and pitch, explaining that this technique grew from an appreciation of the kind of self-similarity found in fractals. He also uses a large-scale frequency modulation technique in which the vibrato depth slowly grows from nothing to a maximum width of a perfect fourth by the middle of the piece. Similar to the first work, various individual partials seem to die out prematurely, and the final sound was abruptly cut off.

The third work, Timbre Study No. 7 (2008), is the longest piece on this CD. The focus on timbre here is very effective, as the composer clearly controls dynamics, spatialization, and the frequency movement of individual partials. Howe uses harsh, sawtooth-like waveforms that gradually trace trajectories along frequency and spatial axes. The result is not unlike the sound of insect swarms. The fused timbres give this piece a sense of unity, even as the composer uses a large variety of inharmonic combinations.

Pi (2011), the fourth piece, uses a four-part formal structure. The first section introduces the sounds, the second expands upon them, the third makes use of inverse relations, and the fourth returns to textures from the expanded second section. The number p is used to create the tuning system and scalar materials for this piece; it is also used to determine the piece's exact length of 3:14.16. This piece has a very wide frequency range, with simultaneously sounding registers used to produce a large, virtual space. Howe also uses a filter that is slowly opened as it sweeps upward through various inharmonic partial series. This is precisely the kind of thing that Csound does so well.

Macro Structure 2 (2006) cleverly uses macros, the mapping of inputs to outputs, to define this work's large-scale formal plan, as well its harmonic content. Sounds that are hard-panned receive no reverb treatment, whereas those that occupy more central locations are saturated in reverb. The result carves out an intriguing, viscerally felt space.

19-Tone Clusters (2010) is a 19-tone "translation" of the first piece, Clusters, though it is a minute...