Prism, Mirror, Lens

from by Dave Seidel

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Prism, Mirror, Lens (2014) is a piece for Shnth and realtime Csound processing. It utilizes pure tunings, complex timbres, and sounds of long duration, in a setting of continual spectral change. Prism, Mirror, Lens is dedicated to Samuel R. Delany, from whose novel Dhalgren the title is taken.

The Shnth is a new instrument that combines a variety of playing surfaces with a programmable sound engine. It is unusually well-suited to just intonation as it uses integer ratios to describe all pitch relationships. The audio produced by the Shnth is transformed and augmented by a Csound program controlled using the knobs on a device called a rePatcher, allowing the performer to manipulate several aspects of the sound.

Harmonically, the piece consists of a series of ten dyads from a just intonation version of a Bohlen-Pierce variant scale, connected by common tones. These dyads are played on the Shnth. The Csound processing transforms the dyads into complex chords based on various mathematical relationships between the dyad's pitches, including sum, difference, product, quotient, and Pythagorean means (arithmetic, geometric, and harmonic). The Csound program also produces several layers of Risset harmonic arpeggios, as well as several simultaneous binaural beating patterns. The harmonic arpeggios and binaural beating are heard throughout; chords are brought in and out as successive layers as each dyad is played.

Prism, Mirror, Lens was premiered in a shorter version at Electronic Music Midwest (Lewis University, Romeoville, Illinois, U.S.A.) on October 17, 2014.

Hardware: Shnth, rePatcher with Arduino Uno R3, Linux laptop, Scarlett 4i2 audio interface. Software: Csound, and a Processing program writen by J. Siemasko that translates rePatcher output into OSC. Recorded in 96k/24-bit stereo on a Zoom H4N recorder using direct output from the Scarlett 2i4, normalized and exported as a 48k/24-bit FLAC file using Audacity.


from Prism, Mirror, Lens, released August 30, 2015




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