An audio system and a method of using the audio system to generate a head-related transfer function (HRTF) map, are described. The audio system can determine one or more HRTF and corresponding HRTF locations along an azimuthal path of an azimuth extending around a head of a user. The HRTFs or HRTF locations can be measured, and other HRTFs or HRTF locations can be interpolated or extrapolated. The HRTF map can include the HRTFs assigned to HRTF locations along the azimuth. HRTFs from the HRTF map are used to render spatial audio to the user. Other aspects are also described and claimed.