Cross Modulated Microtonal Improvisation

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I created this plucky microtonal patch by using the cross modulation on the Roland MKS-80 to effectively put the instrument into an instable, out-of-tune state. I mentioned in my previous entry that cross modulation is a form of frequency modulation or FM synthesis made famous by the Yamaha DX-7. My curiosity about this technique led me to an article in Sound on Sound from 1994 titled Exploring Analogue (Part 2) by Steve Howell. In the article Howell states,

“…take the output of one oscillator (Osc A) and feed it into the control input of another (Osc B). As the modulation level at Osc B’s input is increased, so its tonal quality becomes progressively nastier. In fact, in the absence of a ring modulator, cross-modulation can be used very effectively to create clangorous bell sounds and the like. But be warned! Because the tuning stability on old analogue synths leaves much to be desired, the oscillators don’t track too well, and a sound that is perfectly tuned on C3 may well have disintegrated by the time you get up to F3.”

On the Roland MKS-80 the tuning stability is pretty good, but it does use VCOs (voltage controlled oscillators), so they won’t track as well as DCOs (digitally controlled oscillators). This imperfection is part of what many of us find attractive about analogue synthesis, and what made it possible for me to produce this bizarre, out of key, yet delightful sound.

Cross Modulated Microtonal Improvisation

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About John CS Keston

John CS Keston is an award winning transdisciplinary artist reimagining how music, video art, and computer science intersect. His work both questions and embraces his backgrounds in music technology, software development, and improvisation leading him toward unconventional compositions that convey a spirit of discovery and exploration through the use of graphic scores, chance and generative techniques, analog and digital synthesis, experimental sound design, signal processing, and acoustic piano. Performers are empowered to use their phonomnesis, or sonic imaginations, while contributing to his collaborative work. Originally from the United Kingdom, John currently resides in Minneapolis, Minnesota where he is a professor of Digital Media Arts at the University of St Thomas. He founded the sound design resource, AudioCookbook.org, where you will find articles and documentation about his projects and research. John has spoken, performed, or exhibited original work at New Interfaces for Musical Expression (NIME 2022), the International Computer Music Conference (ICMC 2022), the International Digital Media Arts Conference (iDMAa 2022), International Sound in Science Technology and the Arts (ISSTA 2017-2019), Northern Spark (2011-2017), the Weisman Art Museum, the Montreal Jazz Festival, the Walker Art Center, the Minnesota Institute of Art, the Eyeo Festival, INST-INT, Echofluxx (Prague), and Moogfest. He produced and performed in the piece Instant Cinema: Teleportation Platform X, a featured project at Northern Spark 2013. He composed and performed the music for In Habit: Life in Patterns (2012) and Words to Dead Lips (2011) in collaboration with the dance company Aniccha Arts. In 2017 he was commissioned by the Walker Art Center to compose music for former Merce Cunningham dancers during the Common Time performance series. His music appears in The Jeffrey Dahmer Files (2012) and he composed the music for the short Familiar Pavement (2015). He has appeared on more than a dozen albums including two solo albums on UnearthedMusic.com.

5 thoughts on “Cross Modulated Microtonal Improvisation”

  1. Pingback: Audio Cookbook » Blog Archive » Clangorous Cross Modulated Analogue Bells

  2. Beautiful sounds and tuning scheme! The upper register is particularly nice. I’m not sure how easy it would be to put together a polyphonic texture, but I’m curious to hear what thick chords would sound like.

    The intermingling of tuning and timbre you mention reminds me an interesting book by Bill Sethares called “Tuning, Timbre, Spectrum, Scale,” which discusses, surprisingly enough, the relations between those four musical properties. Sethares describes how timbres can be designed to optimally fit a microtonal scale and vice versa.

  3. @patrick Thanks! This is actually a polyphonic patch, I was just playing single notes, so harmony is something I might explore. Unfortunately I don’t have very predictable control over the tuning of the scale. I would love to experiment with more tuning schemes, but this technique doesn’t allow for specific programming of the intervals. I’d love to know if there is a way to do this. It it were CV versus MIDI it’d be possible. Yet another path to investigate! ;)

  4. Pingback: Pendulum from In Habit: Living Patterns | Audio Cookbook

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