Musical Instrument Classification

At various times, and in various cultures, various schemes of musical instrument classification have been used.

The most commonly used system in use in the west today divides instruments into string instruments, wind instruments, brass instruments and percussion instruments. However other ones have been devised, and some cultures also use different schemes.

The oldest known scheme of classifying instruments is Chinese and dates from the 3rd millennium BC. It groups instruments according to what they are made out of. All instruments made out of stone are in one group, all those made out of wood in another, those made out of silk are in a third, and all those made of bamboo in the 4th, as recorded in the Yo Chi (record of ritual music and dance), compiled from sources of the Chou period (9th-5th centuries BC), and corresponding to the 4 seasons and 4 winds (Kartomi, 1990).

The 8-fold system of pa yin ("8 sounds"), from the same source, occurred gradually, and in the legendary Emperor Shun's time (3rd millennium BC) it is believed to have been presented in the following order: metal (chin), stone (shih), silk (ssu), bamboo (chu), gourd (p'ao), clay (t'u), leather (ko), and wood (mu) classes, and it correlated to the 8 seasons and 8 winds of Chinese culture, autumn and west, autumn-winter and NW, summer and south, spring and east, winter-spring and NE, summer-autumn and SW, winter and north, and spring-summer and SE, respectively (Kartomi, 1990).

However, the Chou-Li (Programs of Chou), an anonymous treatise compiled from earlier sources in about the 2nd century BC, had the following order: metal, stone, clay, leather, silk, wood, gourd, and bamboo. The same order was presented in the Tso Chuan (Tso Commentary), attributed to Tso Chiu-Ming, probably compiled in the 4th century BC (Kartomi, 1990).

Much later, Ming dynasty (1300s-1600) scholar Chu Tsai Yu recognized 3 groups: those instruments using muscle power or used for musical accompaniment, those that are blown, and those that are rhythmic, a scheme which was probably the 1st of scholarly type, the other earlier ones being traditional, folk taxonomies. (Margaret Kartomi, 2011, Upward and Downward Classifications of Musical Instruments-musicology.ff,cuni.cz)

More usually, instruments are classified according to how the sound is initially produced (regardless of post-processing, i.e. an electric guitar is still a string-instrument regardless of what analog or digital/computational post-processing effects pedals may be used with it).