A detailed analysis of the pat wain, a drum circle was made, in terms of its tuning and modes.
Kyaw Zay playing the pat wain solo at his house in Myitkyina, Kachin State, Myanmar.
Tuning the instrument is done by adding a pates of rice and ashes.
The modes of the pat wain alter according to the amount of paste added. Below are Finite-Difference simulations of the drum head eigenfunctions while adding more and more paste. At the left no paste is used and towards the right the paste ring is increased until the whole pat wain is covered with paste. The rows show similar modes with increasing frequencies from top to bottom.
Bader, R.: Finite-Difference model of mode shape changes of the Myanmar pat wain drum circle using tuning paste. Proc. Mtgs. Acoust. 29, 035004 (2016); doi: 10.1121/2.0000450