Osan Bulala The Iyá Alu ("Mother") is the giant drum and leads the group, playing long, complex patterns with many variations and initiating conversations with the other two drums. The drums of Iyá are often adorned with bells and bronze caps called Chaworo, which enhance their vibrations and timbre when they are played. in Yorubaland, the Batá drum has different parts. These parts include the Igi Ilu, the leather, Egi Ilu, Osan, Iro,and Bulala. Igi Ilu: The Igi Ilu is the wooden framework of the drum. The leather:There were two piles of leather attached in the Batá drum: one is to bring out the tone in the instrument, while the other is used to cover the first leather. Egi Ilu:The Egi Ilu that holds the leather to the wooden frame. This part of the drum is usually constructed with small bunches of thick brooms, called Igbale gbaro.