An apparatus for manipulating a body in a liquid mass comprising a plurality of acoustic radiation transducers in a phased array, control means for activating individual transducers in the phased array, said control means including an electrical connection between each transducer in the pattern, and an electrical signal, said electrical signal originating in a signal generator circuit, said signal generator circuit including a radio frequency power amplifier circuit, means for focusing the transducers on a target, and a boundary physically separating, and acoustically coupling the transducers and the liquid mass.