Active structural acoustic control focuses on implementing vibration-based control on a structure with the objective of achieving attenuation of the radiated acoustic field. It has been shown that utilizing control metrics that are integrally associated with the desired control result will generally lead to greatly improved control results. The weighted sum of spatial gradients (WSSG) method has been developed to provide global attenuation of the acoustic field radiated from a structure. It utilizes multiple spatial gradients that form the control metric, and which are correlated with various radiation mechanisms associated with the structure. The WSSG method will be briefly overviewed and the implementation of the method will be discussed. It will also be shown that the method is related to the concept of acoustic radiation modes, which have been used to describe radiation from structures. The WSSG method has been applied to several types of structures, and both computational and experimental results will be shown for flat plates and cylindrical shells to demonstrate the effectiveness of the control method.