Simulation free field hearing by head phones by means of digital filter technics was used to investigate directional hearing and audiocinetic vection in microgravity. Our data showed basic informations for the understanding of the reciprocal influence of vestibular and auditory inputs for dynamic orientation. The technical equipment of free field hearing simulation by headphones and the performed experiments are described in detail. Furthermore the new established technology is discussed in terms of the value in psychoacoustic research as well as in clinical practice.