Geta Bera drum acoustic tuning: applying moist rice paste (Mangullama) before dawn temple rituals?

The Geta Bera (the classical drum of the Kandyan kingdom) features two distinct acoustic heads. The left head (Bamba), crafted from cowhide or calfskin, produces the deep, resonant bass tone. To tune this membrane, drummers apply a freshly mixed circular paste called Mangullama or Bera Batha—composed of boiled sticky red rice, ash of Jak wood, and fine iron rust powder. The paste adds physical mass to the center of the leather membrane, lowering its fundamental resonant frequency and dampening unwanted high-frequency surface overtones to create a deep bass thump.