Thai classical music is synonymous with those stylized court ensembles and repertoires that emerged in its present form within the royal centers of Central Thailand some 800 years ago. These ensembles, while being deeply influenced by Khmer and even older practices and repertoires from India, are today uniquely Thai expressions. While the three primary classical ensembles, the Piphat, Khruang Sai and Mahori differ in significant ways, they all share a basic instrumentation and theoretical approach. Each employ the small ching hand cymbals and the krap wooden sticks to mark the primary beat reference. Several kinds of small drums (klong) are employed in these ensembles to outline the basic rhythmic structure (natab) that is punctuated at the end by the striking of a suspended gong (mong). Seen in its most basic formulation, the classical Thai orchestras are very similar to the Cambodian (Khmer) pinpeat and mahori ensembles, and structurally similar to other orchestras found within the widespread Southeast Asian gong-chime musical culture, such as the large gamelan of Bali and Java, which most likely have their common roots in the diffusion of Vietnamese Dong-Son bronze drums beginning in the first century BCE.