There are three main categories of Thai instruments, with numerous examples in each category. All of those different instruments are used to create a wide variety of music. However, beginning in the royal courts about 800 years ago there were three main genres.
Classical Thai music was heavily influenced by Khmer and Indian roots, but has a unique Thai flair and sound. Stylistically, classical Thai music has similarities to American Folk music, in that each instrument improvises a basic line or harmony. Where Western music typically emphasizes the first beat of of a measure and has a mixture of tones and semitones, classical Thai music emphasizes the final beat of a measure and has a scale of seven tempered notes.
There are three distinct genres of classical Thai music: piphat (ปี่พาทย์), khrueang sai (วงเครื่องสาย) and mahori (มโหรี). All three types use the small ching hand cymbals and krap wooden stick to establish the primary beat.
Piphat
The piphat is considered the most sacred and “high-class” of the styles of Thai music, traditionally used for the masked khon dances and the Buddhist invocation called sathukan (สาธุการ).
A piphat ensemble includes the pi (a quadruple-reed oboe), xylophone, gong chimes and other percussion instruments, played using hard mallets.
There is a quieter type of piphat, called a piphat mai nuam (ปี่พาทย์ไม้นวม), which uses soft mallets, includes the khlui phiang o instead of the pi and sometimes the saw u. There are different kinds of piphat ensembles with different names that correspond to the number of instruments included, how the instruments are arranged and the ceremony that the ensemble is playing for.
Here’s a video of a piphat ensemble:
Khrueang Sai
Khrueang sai literally translates as a “string ensemble,” and typically features a saw duang, a saw u, a jakhe, a khlui, drums and cymbals. It’s typically pretty quiet and intimate and is used for singing, dances and holidays. Again, there are different types of khrueang sai ensembles that depend on the number and kinds of instruments included.
Here’s a video of a khrueang sai performance:
Mahori
If you take the percussion parts of the piphat ensemble and combine it with the strings of the khrueang sai ensemble then you have the mahori ensemble. Traditionally, the mahori ensemble was made up of women in the courts who used to use smaller instruments (now they use normal-sized instruments).
Like the other types of classical music, there are different sizes of mahori ensembles with different names. Mahori also typically has a vocalist that plays a prominent role.
Here’s a video of a mahori performance:
Classical Songs
Most classical songs were passed down through an oral tradition and composers have been forgotten to time. Since the Bangkok era, pieces have been attributed to composers. However, pieces are considered rather fluid and open to interpretations, with performers often improvising within the context provided by the structure of the composition.