Methods and apparatus include headphones that determine a size of a head of a listener and a shape of an ear of the listener. The size of the head and the shape of the ear determine head-related transfer functions (HRTFs) that are customized to the listener. The headphones include head tracking, and sound is adjusted so that a location of a source of the sound continues to originate from a fixed sound localization point (SLP) in empty space that is at least one meter away from the head of the listener while the head orientations of the listener change with respect to the fixed location.