The spatial spillover operator quantifies the relative effectiveness of a controller at two different spatial locations. This operator is relevant to noise and vibration control, where the response of the system at a location without a sensor may be unsatisfactory. Identification of the spatial spillover operator based on a representation involving four transfer functions requires measurements of the disturbances, which may not be available in practice. Likewise, identification based on a representation involving two transmissibilities is not feasible in systems where the disturbance cannot be suppressed. To overcome this difficulty in systems with disturbances that are both unmeasured and insuppressible, this paper considers identification based on a hybrid representation involving one transmissibility and two transfer functions. Acoustic data are used to identify the spillover operator and validate the proposed method.