An apparatus is provided that includes a plurality of portable wireless transmitter units, a plurality of digital receiver modules that alternate transmitting wireless synchronization pulses and that receive information from the plurality of transmitter units synchronized to the synchronization pulses, a receiver control unit in communication with each of the receiver modules that coordinates transmission of synchronization pulses among the plurality of digital receiver modules in accordance with a predetermined transmission sequence and a system that receives the information from at least some of the microphone transmitter units through the receiver modules and delivers the information exclusively to a geographic area proximate a source of the audio information.