The purpose of this paper is to study the acoustical model of the Thai traditional duct flute, khlui. The relation between physical characteristics of the flute, such as acoustic length, playing hole, temperature effect, etc., and the frequency of each musical note of khluis is investigated. First, the fundamental frequencies of each finger hole of 10 khluis are measured. Then, data between the ideal musical notes and measured notes of khlui are analysed. The results indicate that the production process of khlui still has limits in accuracy. Finally, in order to develop a production standard of the Thai duct flute, a model of khlui is designed. The musical notes of the designed flute are measured. The accuracy of the designed flute is investigated to support the understanding of its acoustical model.
