Mridanga is a percussion musical instrument, the sound of which is produced by the vibration of a stretched membrane, thus falls into its subgroup Membranophone. In music, percusion instruments are used to control the beat or Tala, and in carnatic music mridhangam is the main instrument used for controlling the Tala, though Ghatam, Tavil, Morseng etc too are liberally employed.
Traditional Mridangam is made of hollowed wooden body, generally of Jackfruit tree. The two ends are covered with stretched skins. They are anchored by leather straps hoped through holes drilled at the edges of the the membrane. Tension is adjusted to tune the Sruti of the mridhangam by means of positioning the wooden pegs inserted between the underside of the straps and the body of the drum. The instrument is usually tuned with a small wooden block and a heavy stone. The block is placed against the rawhide weaving and struck with the stone. The manner of striking may either raise or lower the pitch. It is generally tuned to the tonic of the piece being performed.
One end of mridhangam is smaller in diameter, and is struck with the right hand fingers. On this face, the centre portion is covered with a solid hard dry paste (made out of starch and ground black granite stone powder) to improve the tonal quality. Care is taken to keep this face always dry. The other side, the larger diameter side, to the the centre portion of the diaphragm a thick moist paste of wheat flour is applied to improve the lower pitch. This paste is kept moistened during the recital by adding moisture and this paste is removed before storing the instrument after use
The instrument is played while squatting on the floor, the smaller end portion supported over the right ankle of the player. Generally the mridhangam player (right handed) sits on the right side of the vocalist facing him so that the right side of the mridhangam faces the audience.
Like any percussion instrument mridhangam is used in controlling the Tala in Carnatic recitals.