From Academic Kids
The Dholak (sometimes dholaki) is a classical North Indian hand drum. A dholak may have traditional lacing or turnbuckle tuning. The dholak has a simple membrane on the right-hand side. The left-hand membrane has a special coating on the inner surface. This coating is a mixture of tar, clay and sand (dholak masala) which lowers the pitch and provides a well-defined tone. The dholak is the main accompaniment instrument of the Qawwali.