Advanced Audio and Virtual Human Sensory Interfaces: Improved Algorithm for Controlling Distance in 3-D Audio Displays

The project goal is to produce an algorithm for synthesizing auditory distance which will be accurately perceived with little or no learning required. The algorithm could be added to an existing AF 30D audio system which uses headphones in a noise-reducing helmet. The approach is to combine very accurate recently developed atmospheric modeling with head-related transfer functions (HRTFs) to produce the most realistic simulation of outdoor sound propagation achieved to date. There are four technical objectives: (1) Demonstrate that realistic atmospheric modeling, including HRTFs for azimuth and elevation, provides effective distance cues. (2) Demonstrate that reference sounds, properly located in elevation, azimuth, and distance, provide accurate absolute distance cues. (3) Determine how listener training and learning affect performance. (4) Establish a range of distances which can be encoded, considering expected cockpit noise levels.