The SwarShala Indian music software includes Eddaka and over 100 other perfectly sampled virtual Indian instruments.
Eddaka is made of two circular rings on which two drumheads are mounted. The body, which looks like an hourglass, is connected to the two drum heads by special laces. The laces are used to pull the two rings towards the drumheads. The drum heads must be closer to the open end of the hourglass. In some cases, the circumference of the drum head can be larger than the circumference of the hourglass structure.
Eddaka is a close cousin to the Damaru instrument, but the difference lies in its operation. Whereas Damaru is played by shaking the cords that look like hooks, the Eddaka is struck by a stick.
Being both a percussion and an acoustic instrument, Eddaka is played by striking the drumhead with a stick or your hands. This produces the same sound like that produced by a drum. The difference comes in when the laces are tightened and loosened. The tightening and loosening of these laces pull the drum head towards the body and release it at intervals. This is very crucial in producing sounds of varying pitches.
Eddaka is widely used in India, mainly in the South but also in Central and Western part of the country.