Abstract: Timpani with quick and accurate tuning are shown. Each of timpani has a motor to drive the mechanism which gives variable tension to the head. Given tone is transformed to period of vibration and then to target displacement value of head rim against body. Motor is driven so that the head rim reaches the target displacement. Parameters of transform function to transform period to target displacement are stored, and updated, when head sounds and pair data of period of head vibration and the displacement are acquired, so that pair data fit the transform function. Combination of tones can be programmed stepwise in advance. In performance, steps are advanced by foot pedal or touch pad and tone changes of timpani are quickly done without sound. Muffling device is equipped and its actions are programmed with tone change.