Ghatam is one of the oldest surviving Indian musical instrument. Ghatam is made of clay and it resembles the shape of an ordinary household pot. However, the instrument is to be manufactured with particular care in order to give it its tonal quality. The pot has a narrow mouth towards which the pot tapers from a ridge. The walls of the instrument must have a uniform thickness to give it a consistent tone. Ghatam is made with clay backed with metallic filling, to give the instrument its ringing tone.
Manamadurai, a town in Tamil Nadu is renowned for manufacturing good quality Ghatams. It is believed that the clay that is from this place plays an important role in the tonal quality of the instrument. Also, a small quantity of brass is added to the clay, which makes the pot harder to play but gives a nice ringing tone to it.
Similar to Mridhangam, Ghatam is a pitched instrument and its key is that of the tonic key of the singer. The pitch of the Ghatam varies by its size – larger the size, lower the pitch. Minute adjustment to the tuning can be made by applying a paste of clay to the instrument.