The active control of the long-wavelength resistive wall mode (RWM) instability is expected to significantly improve the performance of future burning plasmas [1]. While in conventional aspect-ratio tokamaks the RWM has been studied and controlled for over a decade [2], in a high plasma pressure device such as the spherical tokamak (ST), the mitigation, control and understanding of the RWM becomes even more important. We present here a study, which contributes to understanding the physics of RWM stabilization and control, based on the use of a multi-energy SXR array operated on the NSTX spherical tokamak.