Classification of Musical Instruments

Musical instruments can be classified in various ways, all of which consider a number of factors including the process by which sound is created by the instrument, the physical properties of the instrument, the musical range of the instrument, as well as where the instrument belongs in a musical orchestra or similar assembly of instruments. The systems of classification include the ancient system, the range system, the Sachs-Hornbostel system, and the Schaeffner system. Here we consider these methods of classification in more detail.

Ancient System
of Musical Instrument Classification

Dating back to around 100BC, the ancient system of classification groups musical instruments into four main categories, which include instruments that produce sound through vibrating columns of air, instruments that contain strings to produce sound through vibration, wood or metal percussion instruments, and percussion instruments with skin or membrane drums. In later years, this system of classification evolved to the more familiar wind instruments, string instruments, percussion instruments, and drums.

The Range System
of Musical Instrument Classification

Musical instruments may be classified by the musical range they produce according to the Range system of classification. Range system categories include soprano, tenor, alto, baritone, and bass. Soprano instruments include the violin, trumpet, clarinet, and flute; Tenor instruments include the guitar and trombone; Alto instruments include the viola and English horn; Baritone instruments include the cello, bassoon, and bass clarinet; Bass instruments include the double bass, tuba and bass guitar.

Some instruments may produce sound across multiple ranges and hence fall into multiple categories. Examples include the trombone which has the capability of producing sound in the tenor, alto, baritone and bass ranges. Furthermore, some instruments include the range within their name; one example being the saxophone family which can be further sub-divided into the soprano saxophone, tenor saxophone, alto saxophone, baritone saxophone, and bass saxophone.

The Sachs-Hornbostel System
of Musical Instrument Classification

The ancient system of classification was adapted further at the start of the 20th Century by Erich von Hornbostel and Curt Sachs. Known as the Sachs-Hornbostel System, the resulting scheme remains in common use today. In the Sachs-Hornbostel System, musical instruments are again classified into four main groups, namely idiophones, membranophones, chordophones, and aerophones (all of which are discussed further below). A fifth category, known as the electrophones, was in fact added later by Curt Sachs to account for the introduction of electronic musical instruments producing sound through processes powered by electricity.

Idiophones are instruments that produce sound through their own vibration when struck, shaken, plucked or scraped. They may be further classified by their method of operation; examples being percussion, concussion, scraped, plucked, and shaken idiophones.

Membranophones consist of percussion instruments with a stretched skin or membrane producing sound through vibrations from the action of striking this membrane. The most common example of a membranophone is the common drum. Membranophones may be further classified into predrum membranophones, tubular drums, kettle drums, and friction drums, among others.

Chordophones consist of instruments that use stretched cords or strings under tension, a popular example of which is the piano. Sound is produced by string vibrations. Chordophones may be further classified into keyboard chordophones, bowed chordophones, zithers, harps, lutes, and lyres.

Aerophones are wind instruments in which sound is produced through the action of blowing thus creating vibrating columns of air. A common example is the flute. Aerophones may be further classified into flutes, organs, free aerophones, lip-vibrating aerophones, and reedpipes.

The Schaeffner System
of Musical Instrument Classification

Rejecting the Sachs-Hornbostel system based on a belief that the method of playing a musical instrument should not determine classification, Andre Schaeffner developed another system in the 1930s in which musical instrument classification was based purely on the physical structure of the instrument. The Schaeffner System categorised instruments into two basic classifications, namely instruments with solid bodies that vibrated and instruments containing air that vibrated.