Around 2012, I had an idea for a composition involving a choreography of ambulances. I had been living on a busy street in Berlin and was fascinated by the Doppler Effect, defined as the changing in frequency of a wave in relation to an observer who is moving relative to the source of the wave. Having been politely yet firmly convinced of the impracticality of commandeering a fleet of emergency vehicles, I began experimenting with sound pendulums—a fancy name I made up for a loudspeaker attached to a string that can be swung around in the air. When these loudspeakers play simple sound waves, the Doppler Effect is audible, like with ambulances, on a smaller, more subtle scale. Depending on their relative position to the instruments, each listener finds herself in a microscopically different musical world. As Joseph Conrad wrote, “We live—as we dream—alone.” 

When Arash Yazdani of the Ensemble for New Music Tallinn generously asked me to compose this piece for the group, I was working a nine-to-five office job, meaning that Motion Harmony #6 hews to largely familiar sounds. It includes microtonal variations on single pitches, interactions between different types of artificial wave forms, and explorations of the ways the perception of the Doppler Effect changes with register. I’m particularly fond of the neutral third, an interval poised strangely between a major and a minor third that sounds like neither, which appears toward the middle of the work—though the pendulums’ Doppler Effect allows it to creep into a more familiar realm. 

Jeffrey Arlo Brown