The ElectroMagical Spectrum
Video collage with poetic & acoustic accompaniment, 2013

Words & collage: George Petros
Soundscape & oscilloscope: Robert Lund

The ElectroMagical Spectrum combines electromagnetism and magic. It comes from two sources: solar processes that produce power, and life processes that produce consciousness.

This video collage attempts to portray the forces found along that spectrum. Most of these video clips come from YouTube sources, with the remainder coming from educational film archives and NASA collections. The opening clip shows the screen of a Tektronix 453 oscilloscope, vintage 1966, as it graphs the opening track ("Main Title Overture" by Louis & Bebe Barron) from the 1955 Sci-fi masterpiece Forbidden Planet. Subsequent clips include brief segments of The Joshua Light Show's "Liquid Loops" circa 1969, Astral Projection Liquid Sun from Cannabeo 2007, ICTV1 Day Glo Party 2010, and John Sutherland's 1953 General Electric-sponsored classic A Is For Atom. The clips were compiled using iMovie HD and QuickTime 10.

The soundscape accompanying the narration consists entirely of Shepard-Risset tones. To visualize an example, start with one voice, smoothly sweeping up in pitch across three octaves, say C1-C4; only, it starts out at zero volume, fading in to full volume after one octave; maintains full volume for another octave; and fades away to zero again while sweeping up the final octave. Since it's silent, it can shift suddenly down three octaves and repeat. Voice 2 does the same thing, only it starts fading up from C1 just as voice 1 reaches C2; and these two go along sweeping, an octave apart. Voice 3, of course, comes in an octave later. The sound of these three voices combined will produce the aural illusion of a continuously rising pitch, even though the overall spectrum of the sound remains the same. The effect is often described as a "sonic barber pole." Many different illusions can be created by varying the number of voices, the spacing between the voices, the range, speed, and direction of pitch change, and other paramters.

An audio program called Endless Series V3 by Oli Larkin provides an interface for generating such tones. The program was run on a MacBook running Mac OS X, with the program output recorded to disk using WireTap Pro. A number of tracks with different textures were recorded and mixed to the video using GarageBand.