Hornbostel-Sachs: Encyclopedia II - Hornbostel-Sachs - The skeleton of the system

Hornbostel-Sachs - The skeleton of the system

Formally, Hornbostel-Sachs is based on the Dewey Decimal classification. It has four top level classifications, with several levels below those, adding up to over 300 basic categories in all. The top two levels of the scheme, with explanations, are shown below:

• 1. Idiophones - sound is primarily produced by the actual body of the instrument vibrating, rather than a string, membrane, or column of air. In essence, this group includes all percussion instruments apart from drums, as well as some other instruments.
  • 11. Struck idiophones - idiophones set in vibration by being struck, for example cymbals or xylophones.
  • 12. Plucked idiophones - idiophones set in vibration by being plucked, for example the Jew's harp or mbira
  • 13. Friction idiophones - idiophones which are rubbed, for example the nail violin, a bowed instrument with solid pieces of metal or wood rather than strings.
  • 14. Blown idiophones - idiophones set in vibration by the movement of air, for example the Aeolsklavier, an instrument consisting of several pieces of wood which vibrate when air is blown onto them by a set of bellows.

• 2. Membranophones - sounds is primarily produced by the vibration of a tightly stretched membrane. This group includes all drums and kazoos.
  • 21. Struck drums - instruments which have a struck membrane. This includes most types of drum, such as the timpani and snare drum.
  • 22. Plucked drums - these are drums with a knotted string attached to the membrane. When the string is plucked, it passes the vibration on to the membrane, which vibrates to give the sound. Some kinds of Indian drums are like this. Some commentators believe that instruments in this class ought instead to be regarded as chordophones (see below).
  • 23. Friction drums - drums which are rubbed, either with the hand, a stick, or something else, rather than being struck.
  • 24. Singing membranes - this group includes kazoos, instruments which do not produce noise of their own, but modify other noises by way of a vibrating membrane.

• 3. Chordophones - sound is primarily produced by the vibration of a string or strings. This group includes all instruments generally called string instruments in the west, as well as many (but not all) keyboard instruments, like pianos and harpsichords.
  • 31. Simple chordophones - instruments which are in essence simply a string or strings and a string bearer. These instruments may have a resonator box, but removing it should not render the instrument unplayable (although it may result in quite a different sound being produced). They include the piano therefore, as well as zithers, the musical bow, and various types of non-western harp.
  • 32. Composite chordophones - acousitc and electro-acostic instruments which have a resonator as an integral part of the instrument, and solid-body electric chordophones. This includes most western string instruments, such as violins, guitars and the orchestral harp.

• 4. Aerophones - sound is primarily produced by vibrating air. The instrument itself does not vibrate, and there are no vibrating strings or membranes.
  • 41. Free aerophones - instruments where the vibrating air is not enclosed by the instrument itself, for example an old car horn, or the bullroarer.
  • 42. Wind instruments - instruments where the vibrating air is enclosed by the instrument. This group includes most of the instruments called wind instruments in the west, such as the flute or French horn, as well as many other kinds of instruments such as conch shells.

A fifth top-level group, electrophones, instruments which make sound primarily by way of electrically driven oscillators, such as theremins or synthesizers, was added later. Sachs himself seems to have acknowledged such a separate group in his 1940 book The History of Musical Instruments, where it is listed informally on the same level as the four primary classifications. However, no official references to a proper classification of the electrophones with numerical subdivisions appear to exist, and the original 1914 version of the system did not acknowledge their existence.

Adapted from the Wikipedia article "The skeleton of the system", under the G.N U Free Docmentation License. Please also see http://en.wikipedia.org/wiki