Musical instrument classification

In organology, the study of musical instruments, many methods of classifying instruments exist. Most methods are specific to a particular cultural group and were developed to serve the musical needs of that culture. Culture-based classification methods sometimes break down when applied outside that culture. For example, a classification based on instrument use may fail when applied to another culture that uses the same instrument differently.
In the study of Western music, the most common classification method divides instruments into the following groups:

String instruments ;
Wind instruments ;
Percussion instruments; and
Electronic instruments
Classification criteria

The criteria for classifying musical instruments vary according to point of view, time, and place. The many different approaches consider aspects such as the physical characteristics of the instrument, the manner in which the instrument is played, the means by which the instrument produces sound, the quality or timbre of the sound produced by the instrument, the tonal and dynamic range of the instrument, the musical function of the instrument, and the place of the instrument in an orchestra or other ensemble.

Classification systems by their geographical and historical origins

European and Western

2nd-century Greek grammarian, sophist, and rhetorician Julius Pollux, in the chapter called De Musica of his ten-volume Onomastikon, presented the two-class system, percussion and winds, which persisted in medieval and postmedieval Europe. It was used by St. Augustine, in his De Ordine, applying the terms rhythmic, organic, and adding harmonic ; Isidore of Seville ; Hugh of Saint Victor, also adding the voice; Magister Lambertus, adding the human voice as well; and Michael Praetorius.
The modern system divides instruments into wind, strings and percussion. It is of Greek origin. The scheme was later expanded by Martin Agricola, who distinguished plucked string instruments, such as guitars, from bowed string instruments, such as violins. Classical musicians today do not always maintain this division, but distinguish between wind instruments with a reed and those where the air is set in motion directly by the lips.
Many instruments do not fit very neatly into this scheme. The serpent, for example, ought to be classified as a brass instrument, as a column of air is set in motion by the lips. However, it looks more like a woodwind instrument, and is closer to one in many ways, having finger-holes to control pitch, rather than valves.
Keyboard instruments do not fit easily into this scheme. For example, the piano has strings, but they are struck by hammers, so it is not clear whether it should be classified as a string instrument or a percussion instrument. For this reason, keyboard instruments are often regarded as inhabiting a category of their own, including all instruments played by a keyboard, whether they have struck strings, plucked strings or no strings at all.
It might be said that with these extra categories, the classical system of instrument classification focuses less on the fundamental way in which instruments produce sound, and more on the technique required to play them.
Various names have been assigned to these three traditional Western groupings:

Boethius labelled them intensione ut nervis, spiritu ut tibiis, and percussione;
Cassiodorus, a younger contemporary of Boethius, used the names tensibilia, percussionalia, and inflatilia;
Roger Bacon dubbed them tensilia, inflativa, and percussionalia;
Ugolino da Orvieto called them intensione ut nervis, spiritu ut tibiis, and percussione;
Sebastien de Brossard referred to them as enchorda or entata, pneumatica or empneousta, and krusta or pulsatilia ;
Filippo Bonanni used vernacular names: sonori per il fiato, sonori per la tensione, and sonori per la percussione;
Joseph Majer called them pneumatica, pulsatilia, and fidicina ;
Johann Eisel dubbed them pneumatica, pulsatilia, and fidicina;
Johannes de Muris used the terms chordalia, foraminalia, and vasalia ;
Regino of Prum called them tensibile, inflatile, and percussionabile.
Mahillon and Hornbostel–Sachs systems

, curator of the musical instrument collection of the conservatoire in Brussels, for the 1888 catalogue of the collection divided instruments into four groups and assigned Greek-derived labels to the four classifications: chordophones, membranophones, aerophones, and autophones. This scheme was later taken up by Erich von Hornbostel and Curt Sachs who published an extensive new scheme for classification in Zeitschrift für Ethnologie in 1914. Their scheme is widely used today, and is most often known as the Hornbostel–Sachs system.
The original Sachs–Hornbostel system classified instruments into four main groups:

idiophones, such as the xylophone, which produce sound by vibrating themselves;
membranophones, such as drums or kazoos, which produce sound by a vibrating membrane;
chordophones, such as the piano or cello, which produce sound by vibrating strings;
aerophones, such as the pipe organ or oboe, which produce sound by vibrating columns of air.

Later Sachs added a fifth category, electrophones, such as theremins, which produce sound by electronic means. Modern synthesizers and electronic instruments fall in this category. Within each category are many subgroups. The system has been criticized and revised over the years, but remains widely used by ethnomusicologists and organologists. One notable example of this criticism is that care should be taken with electrophones, as some electronic instruments like the electric guitar and some electronic keyboards can produce music without electricity or the use of an amplifier.
In the Hornbostel–Sachs classification of musical instruments, lamellophones are considered plucked idiophones, a category that includes various forms of jaw harp and the European mechanical music box, as well as the huge variety of African and Afro-Latin thumb pianos such as the mbira and marimbula.

André Schaeffner

In 1932, comparative musicologist André Schaeffner developed a new classification scheme that was "exhaustive, potentially covering all real and conceivable instruments".
Schaeffner's system has only two top-level categories which he denoted by Roman numerals:

I: instruments that make sound from vibrating solids:
* I.A: no tension ;
* I.B: linguaphones ;
* I.C: chordophones ; plus drums
II: instruments that make sound from vibrating air

The system agrees with Mahillon and Hornbostel–Sachs for chordophones, but groups percussion instruments differently.
The MSA of René Lysloff and Jim Matson, using 37 variables, including characteristics of the sounding body, resonator, substructure, sympathetic vibrator, performance context, social context, and instrument tuning and construction, corroborated Schaeffner, producing two categories, aerophones and the chordophone-membranophone-idiophone combination.
André Schaeffner has been president of the French association of musicologists Société française de musicologie.

Kurt Reinhard

In 1960, German musicologist Kurt Reinhard presented a stylistic taxonomy, as opposed to a morphological one, with two divisions determined by either single or multiple voices playing. Each of these two divisions was subdivided according to pitch changeability, and also by tonal continuity and continuous, making 12 categories. He also proposed classification according to whether they had dynamic tonal variability, a characteristic that separates whole eras as in the transition from the terraced dynamics of the harpsichord to the crescendo of the piano, grading by degree of absolute loudness, timbral spectra, tunability, and degree of resonance.

Steve Mann

In 2007, Steve Mann presented a five-class, physics-based organology elaborating on the classification proposed by Schaeffner. This system is composed of gaiaphones, hydraulophones, aerophones, plasmaphones, and quintephones, the names referring to the five essences, earth, water, wind, fire and the quintessence, thus adding three new categories to the Schaeffner taxonomy.
Elementary organology, also known as physical organology, is a classification scheme based on the elements in which sound production takes place. "Elementary" refers both to "element" and to something that is fundamental or innate. The elementary organology map can be traced to Kartomi, Schaeffner, Yamaguchi, and others, as well as to the Greek and Roman concepts of elementary classification of all objects, not just musical instruments.
Elementary organology categorizes musical instruments by their classical element:

	Element	State	Category
1	Earth	solids	gaiaphones	the first category proposed by Andre Schaeffner
2	Water	liquids	hydraulophones
3	Air	gases	aerophones	the second category proposed by Andre Schaeffner
4	Fire	plasmas	plasmaphones
5	Quintessence/Idea	informatics	quintephones

Other Western classifications

Classification by tonal range

Instruments can be classified by their musical range in comparison with other instruments in the same family. These terms are named after singing voice classifications:

Higher-than-sopranino instruments: the garklein recorder in C, soprillo saxophone, piccolo, piccolo clarinet, piccolo trumpet
Sopranino instruments: sopranino recorder, sopranino saxophone, treble flute, sopranino clarinet, violino piccolo
Soprano instruments: concert flute, soprano clarinet, basset clarinet, soprano recorder, violin, trumpet, oboe, soprano saxophone, soprano sarrusophone, glockenspiel, celesta
Alto instruments: alto flute, alto recorder, viola, French horn, natural horn, alto horn, alto clarinet, alto saxophone, alto sarrusophone, English horn, xylophone, vibraphone
Tenor instruments: trombone, euphonium, tenor violin, tenor flute, basset horn, tenor saxophone, tenor sarrusophone, tenoroon, tenor recorder, bass flute, tenor drum, harpsichord, harp, guitar, marimba
Baritone instruments: cello, baritone horn, bass clarinet, bassoon, baritone saxophone, baritone sarrusophone
Bass instruments: bass recorder, bass oboe, bass tuba, bass saxophone, bass sarrusophone, bass trombone, bass guitar, bass drum
Lower-than-bass instruments: contrabass tuba, double bass, contrabassoon, contrabass clarinet, contrabass saxophone, contrabass sarrusophone, subcontrabass saxophone, tubax, octobass

Some instruments fall into more than one category: for example, the cello may be considered either tenor or bass, depending on how its music fits into the ensemble, and the trombone may be alto, tenor, or bass and the French horn, bass, baritone, tenor, or alto, depending on which range it is played. In a typical concert band setting, the first alto saxophone covers soprano parts, while the second alto saxophone covers alto parts.
Many instruments include their range as part of their name: soprano saxophone, alto saxophone, tenor saxophone, baritone saxophone, baritone horn, alto flute, bass flute, bass guitar, etc. Additional adjectives describe instruments above the soprano range or below the bass, for example: sopranino recorder, sopranino saxophone, contrabass recorder, contrabass clarinet.
When used in the name of an instrument, these terms are relative, describing the instrument's range in comparison to other instruments of its family and not in comparison to the human voice range or instruments of other families. For example, a bass flute's range is from C₃ to F₆, while a bass clarinet plays about one octave lower.