This paper presents a theoretical study of active structural acoustic control on a double panel vibroacoustic system. The system consists of two vibrating panels, which are structurally and acoustically coupled via elastic mounts and the air in the cavity between the panels. The "source" panel is excited by an acoustic plane wave, while the "radiating" panel radiates sound into free-field. A mathematical model for the problem has been developed, which considers the fully coupled configuration. Two decentralised MIMO feedback strategies for the control of the low frequency noise transmission, active damping and active mass, have been investigated and contrasted. Simulations of the sound transmission through the controlled system have been performed, and the results discussed.