Idakka is an instrument used for Panchavadyam and Sopana Sangeetham performances. It is more musical than rhythmical and is believed that it has been sent to the Earth by Lord Nataraja (Lord Shiva).
Idakka is made of a trunk one-and-a-half feet in length, four inches in circumference in the middle portion and six inches on sides. The right and left heads fixed on the trunk are larger in diameter. Lacing is used to hold the heads to the trunk. Soft skin is used for the heads which can be played similarly, however only one head is used for playing.
The instrument can produce an amazing variety of soft sounds. The sounds differ at the portion facing the hollow space, the trunk and the outer part of the heads. A band tied across the lacing is used to adjust the tone. The sapthaswara (seven basic swaras) and even songs can be played on Idakka.
Idakka is the most divine among the mangala vadyas (auspicious instruments). It has the shape of "kadumthudi", the musical instrument played by Lord Shiva. Idakka is not placed on the floor and is hung near the sanctum sanctorum of the temple when not in use.
It is believed that the instrument represents the Vedas and arts. The four sticks fixed between the strings and the trunk represent the four Vedas. The 64 strings represent the traditional 64 kinds of arts and the six holes, the six sastras. Idakka is mostly used as an accompaniment for Sopana Sangeetham.