A piezoelectric smart panel is a plate structure on which a piezoelectric patch is attached with an electrical shunt circuit. When a sound is impinged on the panel structure, the structure vibrates and the attached piezoelectric patch produces an electrical energy, which can be effectively absorbed by the electrical shunt circuit. Since the energy absorption strongly depends on the vibration mode of the panel structure, many patches are required for broadband noise reduction. Thus, we report a multi-mode shunt damping of a smart panel by using a single piezoelectric patch in conjunction with a blocked shunt circuit. Modeling, shunt parameter tuning and implementation of the blocked shunt circuit along with an acoustic test of the panel are explained. A remarkable reduction of the transmitted noise was achieved for multiple modes of the panel. Since this technology has merits in terms of compactness, low cost, robustness and easiness to install, practical applications in many noise problems can be anticipated.