SLAB is a software-based, real-time virtual acoustic environment rendering system being developed as a tool for the study of spatial hearing. SLAB is designed to work in the personal computer environment to take advantage of the low-cost PC platform while providing a flexible, maintainable, and extensible architecture to enable the quick development of experiments. The software provides an API (Application Programming Interface) for specifying the acoustic scene as well as an extensible architecture for exploring multiple rendering strategies.