This second part to “Chromatic Currents” was produced with the GMS by using a string of lights placed into a large glass vase. I moved the camera around the vase to direct the flow of musical phrases with one hand while I adjusted transposition and note duration settings in the sequencer with my right.
You might notice that the video stimulus does not resemble lights in a vase. This is because I applied a negative filter to the video after capturing the performance. I used a pentatonic scale interspersed with rare dissonant notes and probability distributions in the note durations to give it an eerie awkwardness.
This sound was generated using an instrument that I developed using MaxMSP tentatively titled the Wave Table Glitch Machine. The instrument uses TouchOSC as a controller running on an iPod Touch. I interfaced the accelerometer on the iPod to a filter so that when turned on with a toggle, tilting it on the y axis causes a lowpass filter to effect the sound. By setting a threshold on the z axis, giving the iPod Touch a brisk shake will cause the patch to loop a randomly selected grain of random length from a randomly selected buffer played back at a randomly selected rate. The variety of sounds possible with five short samples is expansive. Here’s a selection of sound produced with just one sample selected.
Etude in 8 Bits for Multitouch Graintable Synthesis:
Chromatic Currents Part I is a generative music piece driven by particles floating in a liquid. No intervention in particle behavior occurred while the piece was being performed using the GMS. The scale was strongly C minor pentatonic, weighted with a Dorian mode by adding less-likely probabilities for D and A. However, every note that was not part of the scale still had a small possibility of occurring. This led to occasional blue or dissonant pitches in the sequence. The possibility of occurrences for any note within a twelve tone chromatic scale led me to the title.
Using a variety of processing techniques I was able to turn several percussion samples into haunting melodic phrases. A few of these phrases are the main themes in this piece from my solo album, Precambrian Resonance by Ostraka (Unearthed Music, 2009). I’m also using Rhodes electric piano that I ran through time expansion and other effects in order to create a slightly warped and distorted tone quality.
Josh Clos produced this documentary short about the GMS recently. He and his colleagues Julie Kistler and Brian Smith shot video during my performance in Downtown Minneapolis with Minneapolis Art on Wheels on May 13, 2009. Later Josh interviewed me in the audio studio at Art Institutes Minnesota where I teach interactive media and audio production. As a student in my audio production class, Josh edited the sound and video together with minimal input from myself. His short illustrates what the GMS does and how I’ve been using it to compose music in real-time.