The Study of Geometric Parameters of the Mong Impact on Natural Frequency

Abstract

The Mong or Tam-tam is sometimes also called Gong, which is a percussion instrument in Thailand. The Mong with boss generates a tone with less shim and a one-key sound. A player has to percuss the Mongs to create a rhythm with a hard rubber mallet. It was originally used for signaling peasant workers in from the fields and telling time in Thai because the Mongs are loud enough to be heard from up to 8 km away. The sound of the Mong is usually generated from the vibration of its own structure. The aims of this analysis were to study the eigen modes and identify the important parameters to generate a natural frequency, in which the boss of the Mong are excited. Finite element analysis and the design of the experiment were used to find the relation of geometric parameters that impact the eigen mode. In this paper, the inertia relief method was used to study the natural frequency of the Mong, while the spectrum analyzer was used to measure the eigen mode. The results showed that the diameter of the horizontal flange and the thickness of the Mong had a significant effect on the eigen natural frequency, which is similar to the Gong. This implies that the thickness and horizontal flange diameter must be increased if wanting to use the Mong with many key tones. The analysis agreed with the actual behavior of the structure of the Gong of Khong Wong Yai.