Using the finite-element method (FEM), glassharp vibration was analyzed. Results show that the glassharp pitch is controllable at the stage of manufacturing. First, the effects of several factors were studied, such as geometry approximation, element type, and the number of division on the accuracy of mode frequencies. Second, it was examined how each mode frequency changes by the fixed position and length of the glassharp stem. The results demonstrate that their influences were of no great importance. Third, the pitch was widely adjustable by changing the swell of the cup. Particularly, it was finely adjustable by cutting a small circular groove inside a bottom of the cup instead of a conventional method.

In this paper, we focus on the control of the tone of a glass harp during the process of manufacturing, and on the analysis of the vibration of the glass harp using a finite element method. First, the effect of various factors on results is studied, such as the element type that enables a good geometries approximation and the number of divisions on the accuracy of mode frequencies. Second, we examine how each mode frequency changes with the bulge of the glass harp. The results demonstrate that the use of a bulge is effective in controlling the pitch and the timbre. Third, the pitch can be varied over a wide range by changing the bulge of the cup. In particular, it can be finely adjusted by cutting the inside bottom of the cup so as to form of a small circular groove instead of using a conventional method, which involves cutting the outside of the cup.