This article offers an alternative for spatializing electroacoustic music using high-density loudspeaker arrays (HDLAs). It describes and contextualizes experimentation with the large array of speakers of the Cube concert hall made during the Spatial Audio Workshop residency at the Moss Arts Center, Virginia Polytechnic Institute and State University in August 2015. The experiments were performed using the implementation of “Granular Spatialisation” (GS), a technique developed by the author for sound diffusion in HDLAs. This is based on the projection of sound using spatial grains of “microdurations,” with ideally one grain individually addressing each speaker of the array. The article focuses on particular aspects of, challenges from, and strategies for using GS for the projection of sound with the Cube’s array of 138 loudspeakers, including four independent subwoofers, while composing a new acousmatic piece that was diffused in the Cube at the end of the residency.