The active compression constrained layer damping (ACCLD) is used for the control of sound radiation from a panel coupled with acoustic cavity. The acoustic cavity consists of five rigid walls while the sixth one is flexible aluminum plate. The plate is partially treated with ACCLD, which consists of viscoelastic material sandwiched between a permanent magnet and an electromagnet. Due to the attraction or repulsion forces generated between the two magnets, a compression or expansion of the viscoelastic layer will occur. The energy dissipation in the viscoelastic layer leads to vibration damping and automatically attenuation of sound pressure level inside the cavity. The ACCLD acts as actuator while a microphone used as semor. The ACCLD is used for controlling the first mode using a single patch at the center of the plate. With these arrangeMents, good vibration damping and good control of sound pressure level were achieved.