For long the traditional function of Thai music was mainly to accompany the sung texts of the classical dance-drama. The melody was therefore subsidiary to the text. Only in this century, under western influence, have words for particular melodies (lakorn dok-dambon) been written.
Particular groups of melodies are assigned to the various moods and activities represented in the drama, just as in the dance certain gestures indicate the feelings of the characters. 36 such melodic groups are usually distinguished: there are, for instance, 13 different tunes to denote anger, 21 to express sorrow and 7 to indicate the Buddhist ideal of contemplation. There are tunes for walking, sitting, standing, conquest, desire, despair, hope, grief, love and so on. The initiated can thus pick up the story from listening to the music.
The tunes have been handed down orally from generation to generation. They have been recorded only after 1930 and almost 1200 are preserved. It was not possible to record the Thai scale in western notation without some compromises. Thai music has an 8-note scale with an octave like in western music, but with seven whole tones. There are no semitones, and harmony in the western sense is unknown. Certain variations are achieved by counterpoint. The time is invariably 2/4 or 4/4.
This produces melodic lines strange to western ears but usually very attractive. It may be noted, that Asian listeners appreciate 20th century French music from Debussy and above all from Ravel.
Instrumental music was developed and cultivated in the Ayutthaya period. All the instruments seem to have been of Indian origin. In 1934 the Fine Arts Department established a collection of old instruments, of which there are about fifty different kinds, often local variations of flutes, stringed instruments, drums and gongs. To accompany the khon and nang dances, the piphat orchestra was developed. It has one wood-wind instrument played like a clarinet. Of the percussion, one group marks the time without definite pitch, and the other plays the melody. To the latter group belong the ranad ek, a kind of xylophone, and the gong wong yai, a circular wooden frame on which hang gongs of different timbres. The gongs and drums are beaten either with the hand or with sticks. A piphat orchestra can number from 5 to 20 players, sometimes more.
In keeping with the cheerful disposition of the Thais, song and dance festivals are popular in country districts. Even today wandering musicians perform at village, temple or family festivities. A favorite amusement is the singing contest in which groups of men compete with groups of women. In this type of extempore music the chorus provides an accompaniment consisting of a succession of meaningless words, the last syllable of which gives the rhyme which the singer must use.
The influence of western music on traditional Thai music has been disastrous. It was probably only as a result of government intervention that the Thais preserved the knowledge of their old ritual chants and their traditional instruments; Prince Damrong, Minister of the Interior during the 1920s, is entitled to the credit of saving them. The University of Fine Arts now maintains a very popular piphat orchestra, the members of which are musicians of the highest quality. The state also concerns itself with the training of young players, and has been encouraged in this course by the interest shown by western visitors.
In the field of classical music, the conductors of the leading orchestras enjoy a high reputation. Visitors can buy in Bangkok records of traditional music arranged for western instruments. But in spite of the great efforts which have been made to preserve and popularize genuine Thai folk music the musical life of the country continues to be dominated by western music.
Many Thais play a musical instrument, and the King himself sets a good example in this respect: he plays several wind instruments and has also composed music himself.
It should be mentioned in conclusion that music plays little place in Theravada monastic life, though fine chanting can be heard in some of the monasteries.