The Sachs-Hornbostel System. A Comprehensive Classification of Musical Instruments

In 1914, German musicologist Curt Sachs and Austrian musicologist Erich Moritz von Hornbostel developed the Sachs-Hornbostel system, also known as the H-S System, as a global and comprehensive method for classifying acoustic musical instruments. The system is based on the location of the vibration that produces sound and allows non-Western instruments to be classified. Even though many contemporary specialists were skeptical about developing such a monumental system, the method is still in use today in the field of organology, a study of musical instruments, and is sometimes considered to be synonymous with instrument classification.

The system was designed to categorize physical collections of instruments, but it has also been adapted for use as an ordering system for digital information about instruments. Hornbostel-Sachs is known for its innovative approach to categorizing instruments, its universality in terms of musical culture, and its use of decimal notation borrowed from bibliographic classification.

The H-S system divides all musical instruments into five categories: idiophones, membranophones, chordophones, aerophones, and electrophones. Each category has subcategories based on how the instrument produces sound. For example, idiophones are differentiated according to the method used to make them vibrate, such as concussion, friction, percussion, plucked, scraped, shaken, or stamped. Membranophones are classified according to the shape of the instrument, such as kettle drums, tubular drums, friction drums, mirlitons, frame drums, pot drums, and ground drums. Chordophones are based on the strings' relationship with the resonator, and the subcategories depend on how the strings are played, such as by bowing or plucking.

However, Sachs and Hornbostel recognized that the method has its limitations, especially when there are instruments with multiple vibration sources at different times during a performance.