ABSTRACT
A characteristic of the human hearing mechanism that allows us to localize sound sources in three-dimensional space. Many physical factors are involved: ear spacing, the frequency-response detecting ability of the inner ear, the shape of the outer ear, and even the shape of the head itself. Indeed, the HRTF is a surprisingly complicated function of four variables: three different space coordinates, as well as frequency. In spherical coordinates, for distances greater than about one meter, the source is said to be in the far field, and the HRTF falls off inversely with range. Most HRTF measurements are made in the far field, which essentially reduces the HRTF to a function of azimuth, elevation, and frequency. Because of the different physical variables involved with HRTF, it is likely that no two single people hear the world in exactly the same way.
