The origins of tabla are not clear but one theory is that it evolved from the phakawaj (a barrel shaped drum with a head on either end which is used with the ancient singing form drupad). An alternative theory is that the tabla evolved from an Arabic drum called the tabal (a pair of drums joined side by side, which are widely used in Morocco).
The tabla is comprised of two drums, the treble and the bass. The bass or male drum is called the bayan or dhaga and has a rounded shell made of metal or brass. The treble or female drum is called the dayan or tabla and has a slimmer, wooden shell. Both drums have a circular patch on the drum skin called the sihai. This is a paste made of iron powder and other ingredients which is applied to give tonal variation.
The tabla is tuned in three stages. First the tension straps which hold the drum skin are adjusted. Then a small hammer is used for 'coarse tuning', striking the pegs on the sides of the drum up or down to take the pitch close to the scale to be played. Finally, the fine tuning is done by striking the outer edge of the drum skin with the hammer.