Sound and shape of pyeongyoung, stone chime and pyeonjong, bell chime

My main research with Tom is about Korean traditional stone chimes, pyeongyoung and bell chimes, pyeonjong which have been allocated as a set of instruments in Korean traditional court music. The vibrational mode frequencies and the frequency ratios of the modes in modern pyeongyoung and pyeonjong have been studied. The modal shapes of stones and bells were mapped by TV holography, by scanning with an accelerometer and animated by STAR. The vibrational mode frequencies and mode shapes of ancient stone chimes are analyzed and their dependence on stone shapes had been studied by using finite element methods. The dependence of mode shapes and frequencies on vertex angle and base curvature suggests that the geometries used in late Chinese bianqing and Korean pyeongyeong may have been selected to give the best sound. Based on the research with Tom, I could extend the study to reconstruct the whangjongeum or scale in Korean traditional instruments. My Korean group have measured frequencies of historical 261 pyeongyeong stones and 236 pyeonjong bells mainly from the 14th to 19th centuries. The frequencies and the frequency ratios of the modes were analyzed by the era of building them.