Classification of Musical Instruments: the Sachs-Hornbostel System

The Sachs-Hornbostel System

The Sachs-Hornbostel system (or H-S System) is a comprehensive, global method of classifying acoustic musical instruments. It was developed in 1914 by two European musicologists, despite their own fears that such a systematic system was nearly impossible.

Curt Sachs (1881–1959) was a German musicologist known for his extensive study and expertise on the history of musical instruments. Sachs worked alongside Erich Moritz von Hornbostel (1877–1935), an Austrian musicologist and expert on the history of non-European music.

Their collaboration led to a conceptual framework based on how musical instruments produce sound: the location of the created vibration. 

A Sound Classification

Musical instruments can be classified by the Western orchestral system into brass, percussion, strings, and woodwinds; but the S-H system allows non-western instruments to be classified as well. Over 100 years after its development, the H-S system is still in use in most museums and in large inventory projects. The method's limitations were recognized by Sachs and Hornbostel: there are many instruments that have multiple vibration sources at different times during a performance, making them difficult to classify.

The H-S system divides all musical instruments into five categories: idiophones, membranophones, chordophones, aerophones, and electrophones.

Idiophones

Idiophones are musical instruments in which a vibrating solid material is used to produce sound.

Examples of solid materials used in such instruments are stone, wood, and metal. Idiophones are differentiated according to the method used to make it vibrate.

  • Concussion—A pair of similar instruments are struck together or struck against each other to create sounds, such as cymbals and castanets
  • Friction—Instruments that produce sound when rubbed. An example of these is musical glasses in which the musician rubs his moistened fingers on the rim of the glasses to produce sound.
  • Percussion—Musical instruments that produce sound by striking or using a striker, such as xylophones, triangles, bells, gongs, and steel drums
  • Plucked—Also known as linguaphones, these are musical instruments that need to be plucked to create sound, such as the Jew's harp in which the player plucks the "tongue" of the instrument.
  • Scraped—Instruments that are scraped to produce sound. Examples of these are cog rattles and washboards.
  • Shaken—Musical instruments that need to be shaken to create sound, such as maracas , thought to have been invented by native Indians of Puerto Rico.
  • Stamping—Instruments that produce sound when stamped on a hard surface, such as the shoes used by tap dancers or Irish clogs.
  • Stamped—When sound is produced by the material itself that's being stamped on.

Membranophones

Membranophones are musical instruments that use vibrating stretched membranes or skin to produce sound. Membranophones are classified according to the shape of the instrument.

  • Kettle Drums—Also known as vessel drums, these are rounded at the bottom and may be tunable or non-tunable. The vibrating membrane is either laced, nailed, or glued to the body and the player uses his hands, a beater, or both to strike it.
  • Tubular Drums—Are further classified into shapes including barrel, cylindrical, conical, double conical, goblet, hourglass and shallow. Tubular drums may either be tunable and non-tunable. Like the kettle drums, tubular drums may be played by using both the hands or a striker and the vibrating membrane is either laced, nailed, or glued to the body.
  • Friction Drums—Instead of striking, the stretched membrane vibrates when there is friction across the membrane. These are non-tunable and the player uses a cord or stick to create sound.
  • Mirlitons—Unlike other musical instruments belonging to the membranophones, mirlitons are not drums. The membranes produce sound with the vibration of a player's voice or instrument. Mirlitons are non-tunable, and a good example of this type is a kazoo.
  • Other membranophones are called frame drums in which the skin or membrane is stretched over a frame such as tambourines. Also, pot drums and ground drums fall under the membranophone category.

    Chordophones

    Chordophones produce sound by means of a stretched vibrating string. When a string vibrates, the resonator picks up that vibration and amplifies it giving it a more appealing sound.There are five basic types based on the strings' relationship with the resonator. 

    • Musical bows—May or may not have resonators; the strings are attached and stretched over a wooden bow.
    • Harps—The strings aren't parallel to the soundboard; harps are plucked or strummed.
    • Lyres—The strings run through a crossbar holding it away from the resonator. Lyres may either be bowed or plucked.
    • Lutes—These instruments have necks; the strings are stretched across a resonator and travel up the neck. Lutes may be bowed or plucked.
    • Zithers—These have a board but no necks; strings are stretched from one end of the board to another end. Zithers may be plucked or struck.

    Chordophones also have subcategories depending on how the strings are played. Examples of chordophones played by bowing are double bass, violin, and viola. Examples of chordophones that are played by plucking are banjo, guitar, harp, mandolin, and ukulele. The piano, dulcimer, and the clavichord are examples of chordophones that are struck.

    Aerophones

    Aerophones produce sound by vibrating a column of air. These are commonly known as wind instruments and there are four basic types.

    • Brasswinds—Made of metal, particularly brass, these instruments create sound through the vibration of a player's lips on the mouthpiece. The air that passes through the player's lips goes to the air column of the instrument and thus creates sound. Examples: trombone, trumpet, tuba
    • Woodwinds—These instruments were originally made only of wood but now other materials are used. On reed instruments like the saxophone and the clarinet, a thin material is placed on the mouthpiece so that when the player blows into it the air is forced to go to a reed and sets it to vibrate. In double-reed instruments such as bassoons and oboes, the material placed on the opening of the mouthpiece is thicker. In woodwinds such as flutes, the player blows air into the edge of a mouthpiece thus creating sound.
    • Free-reed—Refers to wind instruments that have a freely vibrating reed and the pitch depends on the size of the reed. A good example of this type of instrument is the accordion.
    • Free—Free aerophones are those in which the sound is produced by a column of air outside of the instrument itself, such as a bull-roarer or a whip when its cracked. 

    Electrophones

    Electrophones are musical instruments that produce sound electronically or produce its initial sound traditionally and then are electronically amplified. Some examples of instruments that produce sound electronically are electronic organs, theremins, and synthesizers. Traditional instruments which are electronically amplified include electric guitars and electric pianos.

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