The focus of the paper is to control the far-field sound radiation from an arbitrary planar structure using multiple structural sensors, particularly for broadband applications. A number of structural velocity sensors are distributed over the structure for sensing the sound radiation at a particular far-field region for control purposes. Spatial control of structural sound radiation is achieved by constructing a frequency-independent spatial filter that reflects the spatially- weighted sound radiation energy. Thus, the signal produced by the spatial filter can be used as an error signal to be minimised by standard active control methods. A numerical case study on the sound radiation of a flat panel structure is performed to investigate the control performance using the developed frequency-independent spatial filter.