Tombak is the chief percussion instrument of Persian classical music. It is a one-headed goblet-shaped drum that is carved of a single piece of mulberry or walnut wood, and is open on the bottom. Across the larger, upper part of the body is stretched a sheepskin membrane, that is glued into place. Thus, the instrument cannot be tuned; the performer prepares it for a piece by warming the membrane over a heater.
The Tombak is normally positioned diagonally across the torso while the player uses one or more fingers and/or the palm(s) of the hand(s) on the drum head, often (for a ringing timbre) near the drum head’s edge. Sometimes Tombak players wear metal finger rings for an extra-percussive “click” on the drum’s shell. Tombak virtuoso perform solos lasting ten minutes or more.