Since music can be made with the voice, instruments are not necessary, however, to make music--unless the voice itself is considered an instrument, as it often is. If so, then "musical instrument" can be defined simply as "anything that can be used to make music."
History and origins
There is a remarkable diversity of musical instruments across both space and time. The indigenous instruments of China, for instance, are considerably different from the indigenous instruments of Italy, for example. There has also been considerable evolution of the design of musical instruments. None of the instruments that were common in ancient Celtic music, for instance, are still being played in the same form today.
Excluding the human voice, the oldest musical instruments appear to be various forms of flute and drum. Instruments known to date back to antiquity include various stringed instruments such as the harp and--oddly enough, perhaps--the bagpipe.
Many of the musical instruments in common use today evolved from earlier devices which were purely utilitarian in function. For example, various sound devices were used for communication purposes, such as signalling in either battle or hunting. The Romans used a device for battlefield signals which later evolved into the trumpet. In its original form, this sound device produced a sound far from melodic. The common drum is another such utilitarian communication device which eventually began to be used in a musical context.
Another common origin can be seen in devices used as part of ceremonies, religious or otherwise.
And finally, some utilitarian devices produced pleasing sounds as a by-product of their usage. An example is the simple bow and arrow, whereby the plucking of the stretched bow produced a melodic sound. The bow and arrow itself was not a musical instrument, but the sound produced eventually gave rise to a number of plucked string instruments, including the harp.
When these early devices began to be developed into a form where the purpose was listening for pleasure is when they became musical instruments in their own right.
Classification of musical instruments
There are numerous possible ways to classify the nearly 50,000 musical instruments which have thus far been scientifically described. Over the course of time, many different ways have been used. The ancient Chinese employed a system whereby they were classified by the materials out of which they were made. The Indians developed a classification scheme based on the acoustic properties of the devices.
The first European system, that of Jean de Muris, dates to the early 14th century and, in addition to describing several instruments, divided the instruments into three groups, to wit:
- stringed instruments;
- wind instruments; and
- percussion instruments
A similar classification was followed by Virdung in 1511 who also included woodcut illustrations of instruments of his time.
In 1619, Michael Praetorius published a 3 volume work on music theory (Syntagma Musicum), the second volume of which was devoted to organology.
Modern science of organology
The beginnings of modern systematic study of musical instruments, including their classification, can be dated to the mid 19th century, with the publication, in 1863, of Traite general d'instrumentation by Francois Auguste Gevaert. In this work, Gevaert put forth four main categories of instruments: stringed instruments, wind instruments, instruments employing a stretched membrane, and autophonic instruments. These main categories were then divided into sub-categories. For example, wind instruments were sub-divided, inter alia, into bowed, plucked, or percussion strings (piano). Wind instruments could be finger hole, reed, or mouthpiece types.
Between 1880 and 1922, Victor-Charles Mahillon published a catalogue, in 5 volumes totally nearly 2300 pages, of the nearly 3300 instruments in the collection of the Belgian royal conservatory. He classified the instruments in this collection according to the acoustic properties of the instruments (somewhat like the ancient Indian system), using four major categories - chordophones, aerophones, membranophones, and autophones - which were then further sub-divided into smaller categories.
Sachs / Hornbostel system of classification
Expanding on the earlier work of Victor Mahillon, Erich Moritz von Hornbostel and Curt Sachs devised an instrument classification system based on how an instrument produces the vibratory motion to make musical sounds. Designed as a universal classification system for any musical instrument from any culture, the system, first published in 1914, is widely used today by organologists and ethnomusicologists.
- Aerophones - Instruments which use the force of moving air to produce sounds. The air stream could be caused to vibrate by passing over a reed (for example, the clarinet or oboe), or could be caused to vibrate by the lips of the player (for example, the trumpet).
- Chordophone - Stringed instruments which produce sounds as a result of the vibration of a stretched string or wire fixed between two points. The string could be bowed (violin), or plucked (guitar), or struck (piano).
- Idiophone - Instruments which produce sounds as a result of the vibration of the material of the instrument itself without assistance from reeds, strings, or the like. Cymbals are an example of an idiophonic instrument.
- Membranophone - An instrument whose tones are produced by the vibration of a stretched skin or membrane which is typically struck by a stick or mallet. The drum family are membranophones.
- Electrophone - Refers to electronic instruments.
Within each of the major categories above there are sub-categories (such as keyboard chordophones and bowed chordophones within the chordophone category) which are designated numerically so that the structure is somewhat like the Dewey Decimal System for books.
"Symphonic" classification (extended)
This system is based on the composition of the modern symphony orchestra, as extended to include electronic instruments. The tools we have to make music are remarkably diverse, and fall into some commonly-recognized and sometimes overlapping classes:
- Stringed instruments include both bowed string instruments, such as the violin, and plucked string instruments, such as guitars, harps and sitars.
- Wind instruments are sometimes divided into brass such as the trumpet, the tuba, and the trombone, and woodwinds such as the flute and the oboe.
- Keyboard instruments such as the piano, although this is sometimes classified as a stringed or a percussion instrument, and the organ, which is also considered a wind instrument.
- Percussion instruments include such common devices as drums, tambourines, xylophones, Cow Bells, chimes, triangles, and rattles.