"Residual Signal" was a site-specific installation by Carolyn Healy, visual artist, and John JH Phillips, media artist, created in response to the architectural and acoustic character of the Sanctuary on the University of Pennsylvania campus. The artists enjoyed looking, listening, measuring and exploring the Sanctuary during their residency from mid-July through October 2014. Healy was attracted to the high shelf running around the circumference and created a "frieze" of found objects, quietly illuminated. Phillips discovered that the space is a large parabolic dome with many intriguing acoustic features that he integrated into his score. Three ceiling video projections add dynamic counterpoint to the sound and sculpture.