A gamelan, which is a percussion instrument made of bronze from the island of Bali, can be used to play various sounds by changing the shape and size, etc. Of these instruments, the keyboard percussion instrument called Gangsa can create a targeted sound by changing the shape of the sound bar, but the shape parameters do not take into consideration the impact on the sound. In this study, it is thought that the sound emitted by the sound bar originates in an inherent vibration characteristic, and thus the relationship between the shape of the sound bar and the fundamental frequency was examined. In addition, based on the results, sound bars that produce the targeted sounds were designed and produced. The study showed that the impact of the cross-sectional shape on the basic frequency of the sound bar is strong, and thus a characteristic not found in other keyboard percussion instruments is exhibited. In addition, by assuming the fundamental frequency for both end free beams and primary mode, it was possible to design the sound bar from the targeted sound. As a shape characteristic, it was confirmed that a trapezoid cross-sectional shape results in excellent balance that contributes to improved frequency at a limited weight, and the curvature had minimal impact on the fundamental frequency.