An actuator—sensor tile has been developed for use in studies examining the issues involved in actively controlling the reflection and transmission characteristics of generic underwater structures. The tile is 25 cm square and contains a full area actuator, acoustic pressure sensor, and (acoustic particle) velocity sensor. This paper presents the predictive models used in the tile design. Issues addressed include transducer performance, spatial sampling, near-field sensing, internal resonances, and both direct and extraneous coupling mechanisms, all of which can contribute to complicate the system transfer functions. The acoustic characteristics of the final tile were evaluated at the NRL Laboratory for Structural Acoustics (LSA) and these results are compared with predictions.