Abstract: An apparatus for obtaining the farfield directional pressure intensity of a sonorous source placed in a fluid medium from pressure measurements taken in the nearfield of the source is disclosed. An acoustic antenna is placed in the nearfield of the source to map the acoustic pressure nearfield. The antenna consists of either a single receptor, or of two separate receptors, one fixed in position to define the direction and the other variable in position over the acoustic antenna. Each receptor is comprised of two oppositely facing parallel planar arrays of acoustic detectors separated by a predetermined distance. The detectors are arranged in each array in a predetermined matrix. The detector signals from both arrays are processed by either of two different methods, an additive or a multiplicative method, to obtain the farfield directional pressure intensity of the source.