There is a critical need for navigation and orientation aids for the visually impaired. Developing such displays is difficult and time consuming due to the lack of design tools and guidelines, the inefficiency of trial-and-error design, and experimental participant safety concerns. We discuss using a virtual environment (VE) to help in the design, evaluation, and iterative refinement of an auditory navigation system. We address questions about the (real) interface that the VE version allows us to study. Examples include sound design, system behavior, and user interface design. Improved designs should result from a more systematic and scientific method of assistive technology development. We also point out some of the ongoing caveats that researchers in this field need to consider, especially relating to external validity and over-reliance on VE for design solutions.