The UCSB Allosphere is a 3-story-high spherical instrument in which virtual environments and performances can be experienced in full immersion. The space is now being equipped with high-resolution active stereo projectors, a 3D sound system with several hundred speakers, and with tracking and interaction mechanisms. The Allosphere is at the same time multimodal, multimedia, multi-user, immersive, and interactive. This novel and unique instrument will be used for research into scientific visualization/auralization and data exploration, and as a research environment for behavioral and cognitive scientists. It will also serve as a research and performance space for artists exploring new forms of art. In particular, the Allosphere has been carefully designed to allow for immersive music and aural applications. In this paper, we give an overview of the instrument, focusing on the audio subsystem. We give the rationale behind some of the design decisions and explain the different techniques...