Investigation of an interaction effect between sound projectors mounted in an array

Measurements on acoustically small, low-loss projectors in arrays in water have shown that near resonance violent changes in their electrical admittance take place. This behaviour has been investigated by computing theoretical admittance diagrams for a cruciform array and comparing these with the anomalous measured diagrams. The shape of the two sets of diagrams are in agreement so that it can be shown from the analysis that the behaviour is caused by the dominant mutual radiation impedance terms. Near resonance, where the mechanical impedance of the projectors is low, these terms control the phase and amplitude of motion through the water coupling.