We know very little about native musical instruments prior to the pre-Angkor
period. The climate of monsoons has effaced all organic traces. Mostly remain stone and bronze. Two lithophones in the National Museum of Cambodia, as well as numerous cattle bells,
rattle-drums, bronze drums or conchs testify to ancient musical or sound practices.
From the pre-Angkorian period, we know the musical and sounds instruments from three sources: archaeological objects, iconography and epigraphy. The first instrumental iconography dates back to 7th century and the earliest inscriptions mentioning musical instruments to 7th or 8th century. In 9th century only lapidary texts bring us the names of some musical instruments; at that time we don't have any iconography. In 10th century, the temples of Banteay Srei and Phnom Bakheng feature some flutes, drums and cymbals more symbolic than functional. From 11th to 13th centuries on the other hand it is an iconographic firework of instruments from Indian origin but in Khmer style. Angkor Wat, Bayon and Banteay Chhmar unfolded an array of instruments for martial, palatine, entertainment and worship purposes. In 16th century, Angkor Wat offers two frescoes in its central tower (bakan) and two large bas-reliefs in its north gallery on which appear new instruments of exogenous origin.
What have become of these instruments? Come of them survive in Cambodia itself, in the greater South-East Asia region and on the Indian subcontinent. Some remain unchanged, others have changed. But the main change is their vocation and the structure of orchestral ensembles.
Sound instruments used for music or to communicate appear in different contexts:
We know nothing about a possible classificatory approach to the Angkorian instruments. However, it can be seen that the lists of musicians assigned to the temples during the pre-Angkorian period present groupings linked to the terminology of the playing mode which could be translated thus: striking drums (and other instruments ?), clasping cymbals, plucking string instruments. The blown instruments don't have any terminology related of playing technique but are mentioned separately. This classification is modelled on that of India. In a chapter of the Nātya-shāstra, a work revealed in Bhāratha by the god Brahmā and probably a Sanskrit compilation of very ancient texts (prior to the 2nd c. AD), musical instruments are classified into four categories according to morphological parameters that underlie their mode of sound production:
This study is supplemented by the voice, a sound instrument of primary importance among the ancient Khmer.