Construction analysis of the string motion model on Sasando musical instrument

String is one of mathematical modelling object has been studied in the world. In this paper, researchers focus on the construction analysis of the string motion model on Sasando. The purpose of the research is to determine the form of the string motion on Sasando musical instrument and validating the model. Construction analysis was done by identifying problems, variables, parameters, energies, and the forces occur on the string of Sasando. Based on the identifying results, mathematical model that represents the problem of string motion on Sasando expressed as a second-order linear partial differential equation with u denote the vertical displacement experienced by the string at the point x at time t. The first step of the validation test is simulations of mathematical models using Matlab. The result obtained shows the oscillatory motions and the string move towards the equilibrium position. It shows that mathematical model of the string motion on Sasando reliable to real case. However, the result of first step validation test are not sufficient to determine validity of the model and next step validation test are needed to complete this research.