Audio Compost is a web application that enables participants in a single location to contribute sound to an ongoing, collaborative frippertronic loop using their mobile devices and voice. The system tightly synchronizes audio samples across devices using a web object timing server and operates in two modes, centralized and distributed. In the central- ized mode, participants send sound to one main audio out- put and their mobile phones are silent. In the decentralized mode, participants use their mobile devices for both input and output, forming an impromptu swarmed multi-channel audio system. The resulting auditory landscape of voices, noises, and ruminations varies based on the number and composition of participants as well as with parameters set in the system. This paper explores the development, imple- mentation, and performances of Audio Compost at open-air venues and planetariums, offering insights into its interactive and dynamic sonic environment.