Piezoelectric actuator, as one of the components of active vibration control system, influences the effectiveness of vibration reduction. To make the reduction process most effective, the efficiency of all its components must be maximized. Hence, optimizing shape of PZT in terms of efficiency contributes to increasing the efficiency of vibration reduction process. The paper presents an experimental verification of a new approach to optimizing shape of PZT. The objective function was to minimize structure vibrations. The result of optimisation process was PZT shape that most effectively reduces plate vibration. The paper compares the regular PZT shapes with the PZT giving the best efficiency (a-PZT). A simply supported triangular plate was chosen as the research object. An active vibration reduction system using closed-loop control was built to verify the model. The control system was implemented on ESP-32 development board, loudspeaker was used to induce vibrations in the plate. The validity of the optimised PZT shape in active vibration reduction of triangular plates was confirmed by the closed-loop control time courses.