I.

Introduction

Musical Instruments, tools used to expand the limited scope of musical sounds—such as clapping, stamping, whistling, humming, and singing—that can be produced by a person's unaided body. Throughout the world, instruments vary greatly in purpose and design, from natural, uncrafted objects to complicated products of industrial technology. Although sirens, automobile parts, and radios have been employed in avant-garde compositions, this article mainly concerns those specialized implements intended for performing the world's conventional folk, popular, and classical musics.

II.

The Production of Sound

Sound arises from vibration transmitted by waves to the ear. Incoherent, violent vibration is normally interpreted as noise, whereas regular, moderate motion produces tones that can be pleasing. The faster the vibration, the higher the pitch that is perceived. Some pipe organs encompass the full audible range of pitch, approximately 16 Hz (hertz, or cycles per second) to 20,000 Hz, or more than ten octaves, but most instruments have a much more limited compass; indeed, many play only a single note or have no identifiable pitch at all.

The greater the amplitude or power of audio waves, the louder their sound, which in some electronically amplified music can reach a painful, ear-damaging intensity. The timbre, or tone color, of the sound is influenced by the presence and relative strength of overtones, or harmonics, in the sound wave. The perception of timbre, however, is also affected by the duration and location of the sound, and by its envelope, or its characteristics of attack (onset) and decay (which may, for example, be abrupt or gradual, or—especially in attack—may involve transient harmonics). The sounds of musical instruments are caused and modified by three components: (1) the essential vibrating substance (such as a violin string), set into motion by bowing, blowing, striking, or some other method; (2) the connected reflector, amplifier, or resonator (soundboard, tube, box, or vessel); and (3) associated sound-altering devices, among them keys, valves, frets, and mutes.

III.

Systems of Classification

Instruments can be classified in different ways—for example, by their primary materials (metal, wood, earthenware, skin, and so forth, an arrangement followed in East Asia); their social status and appropriate setting (church, military, parlor); or their musical role (rhythmic, melodic, chordal, drone). Since the 2nd century bc, Western audiences have conventionally distinguished among winds, strings, and percussion. This exclusive division, however, does not accommodate instruments such as the piano, which employs both strings and a percussion mechanism; or the aeolian harp, a zither the strings of which are vibrated by the wind. Nor is the familiar distinction of brasses from woodwinds quite logical: Saxophones and orchestral flutes are metal woodwinds, whereas early “brasses” were often made of animal horn (the shofar), wood (the serpent, a bass instrument), or even ivory (the cornetto, a small Renaissance horn).

A comprehensive classification based on acoustical principles was devised in the 19th century. Instrument families are defined in terms of what vibrates to produce the sound. These families are the idiophones—solid, intrinsically sonorous objects; membranophones—taut membranes; aerophones—enclosed or free masses of air; and chordophones—stretched strings. A fifth family, electrophones—oscillating electronic circuits—originated recently.

IV.

Idiophones

The largest, most varied and widespread, and probably the oldest instrument family consists of idiophones. Known at least since the Stone Age, idiophones range in complexity from hollowed logs (slit-drums) of indefinite or tuned pitch that are used rhythmically, often to send signals, to precisely tuned cast-bronze bells that, combined in a carillon, form the most massive and expensive of instruments. Bells vibrate at their rim, whereas gongs—perhaps invented in Southeast Asia by Bronze Age metalsmiths—vibrate at their center. The so-called steel drum or piano pan is a modern Trinidadian gong that produces more than one pitch from its segmented surface. See Bell; Gong.

These examples are known as percussion idiophones because they are all struck with beaters. Such instruments are often played in sets. The xylophone is a set of tuned hardwood bars. In Indonesian music, the saron is a metallophone, made up of bronze bars; the bonang, a set of small tuned gongs. The celesta is a metallophone with a pianolike keyboard. A piano hammer action also strikes the glass bars of the glasschord, a 19th-century English crystallophone. The oldest existing sets of tuned-bar idiophones, excavated in East Asia, are lithophones, made of stone; lithophones were also made in 19th-century England.

Concussion idiophones are struck together, usually in pairs. Turkish-style brass cymbals and Spanish wooden castanets (see Cymbals; Castanets) are the most familiar types, but ivory and bone clappers were common in ancient Egypt. Egyptian worshipers also used the sistrum, a rattle with metal rings fitted loosely on rods. Rattles are normally shaken rather than struck. They include vessel types, with loose rattling objects enclosed in a container; strung rattles, with small, hard objects tied together or to a handle; and frame rattles, such as the sistrum and the Javanese angklung (tuned bamboo tubes sliding within a framework). The jingle, or pellet, bell is a metal vessel rattle, not a true bell.

Other idiophones may be scraped, as is the washboard played in old-time jug bands; or they can be rubbed with a bow (as in a nail violin) or with the fingers. Moistened fingers rub the rims of musical glasses, tuned by partial filling with water (See also Harmonica: Glass Harmonica). Plucked idiophones include the rotating ratchet used as a holiday noisemaker; the African mbira or thumb piano, the many metal or cane tongues which can be individually tuned; and the music box, with its “comb” of flexible steel teeth that are plucked by pins which are on a rotating cylinder.

V.

Membranophones

All true drums belong to the membranophones. A drum has one or two heads of skin or plastic stretched over a resonator or over a narrow frame. Kettledrums, having a single head over a bowl-shaped resonator, are produced in all sizes. Orchestral kettledrums are tuned by means of hand screws or pedals, whereas some non-Western types are tuned with paste or heat applied to the head, or by manipulating the lacing which attaches to the head or heads. Hard and soft beaters offer tonal variety. In India the technique of playing small kettledrums (the baya in the pair called tabla) with the hands is a subtle art.

Cylindrical drums, usually unpitched, vary in size from huge basses drawn on wagons in parades, to shallow, waist-slung drums equipped with snares that intensify the sound. In parts of Africa and the Pacific Islands sacred drums are taboo to the uninitiated; their wood bodies are elaborately carved and decorated, and revered drums occupy huts to which votive offerings are brought. Slender, elongated drums with reptile-skin heads glued on with human blood accompany male ritual dances in New Guinea.

Some Native Americans accompany tribal dances and chants on broad, shallow drums beaten by several players at once. A light hand-held frame drum is played by Eskimo shamans; it resembles Asian shamans' drums. The tambourine is a frame drum that usually has rattles attached to the frame; it is both struck and shaken and is sometimes rubbed.

The rommelpot is a Flemish friction drum played as a toy; rubbing a stick or string protruding through its head causes the head to vibrate. A more important membranophone is the mirliton. Not actually an instrument in its own right, but rather a tone modifier, the mirliton is a thin membrane attached over a hole in a resonator, adding a buzzing quality to the sound. One popular mirliton, the kazoo, disguises the voice. Other mirlitons enrich the tone of instruments as diverse as African xylophones, drums, and Chinese flutes.

VI.

Aerophones

Among aerophones, several different methods are used to set the air in vibration.

A.

Flutes

In flutes a wind stream impinges on an edge, setting up eddies in an enclosed body of air. The wind may come from the player's lungs, a bellows or squeezed windbag, or a mechanical fan. If the resonator enclosing the air is a tube, its length determines the pitch; usually, tone holes in the tube wall are opened or closed to change the sounding length and, hence, the pitch.

In the orchestral flute the lips direct breath against the edge of a mouth hole in the tube wall; such flutes are called transverse, or side blown (see Flute). The Japanese shakuhachi is blown against the sharpened rim of one end. A panpipe is also end blown; each of its pipes gives a different note, according to its length. Some end-blown flutes are blown through one nostril; such “nose flutes” are often considered magical.

In whistles and recorders an internal duct aims the breath against the edge of a hole in the wall; the flue pipes on an organ thus operate like one-note whistles. Some Native American flutes have a duct on the outside of the tube, a system unknown otherwise. The ocarina, a popular ducted flute invented in Italy (about 1860), has a globular resonator rather than a tubular one, giving it a hollow, dark tone. In general, the shape of an aerophone's resonator has a more critical effect on timbre than does its material, because the resonator walls vibrate little, compared to the air within.

B.

Single and Double Reeds

Among reed-vibrated aerophones, the clarinet, saxophone, and their relatives employ a single broad reed of springy cane fastened at one end over a hole in a mouthpiece. The reed responds to breath pressure by beating against the hole many times per second, allowing puffs of wind into the tube to vibrate the enclosed air. The brass-reed pipes of an organ are of this type.

The oboe, bassoon, shawm, and other double-reed instruments produce sound when two slender blades of cane pinch together rapidly, thus interrupting the wind stream passing between them into the resonator. Whereas clarinets have a more-or-less cylindrical tube, oboes have a conical pipe; the different internal shapes foster distinctive patterns of harmonics that give these instruments their characteristic timbres.

C.

Free Reeds and Other Instruments

In free-reed aerophones such as the mouth organ, or harmonica, the accordion, and reed organs (harmonium, melodeon), many brass reeds of graduated size produce the sounds. Under wind pressure each reed vibrates back and forth through a close-fitting aperture. Because the length and shape of each free reed determines its pitch and timbre, no resonator is required; the reed vibrates air in the atmosphere. All Western free-reed instruments evolved from the Oriental mouth organ with multiple pipes (such as the Chinese sheng and the Japanese sho), introduced into Europe in the 18th century.

The bull-roarer, a tapered wood blade whirled around on a string, also vibrates the atmosphere directly without benefit of a resonator. Its unpitched rumble sounds powerful and mysterious. The jew's harp has a twangy tone that arises when the stiff metal or cane reed is plucked in front of the mouth and vibrates the air within.

D.

Lip-Vibrated Instruments

In the orchestral brasses and other lip-vibrated aerophones, the player's lips buzz against a cup- or funnel-shaped mouthpiece inserted in a conical or cylindrical tube. Broadly speaking, conical, wide-bore tubes characterize horns, whereas relatively cylindrical, narrow-bore tubes define trumpets (see Horn; Trumpet). The sounding length of the tube can be altered by means of fingered or keyed tone holes; by valves that open and close sections of tubing; or by a sliding telescopic section of tubing, as on the trombone. The cornetto and serpent, for example, have finger holes much like those of a recorder. The keyed trumpet and keyed bugle (see Bugle) became obsolete only when valves were widely adopted for brasses in the 19th century. See also Tuba.

In many aerophones, overblowing (drastically increasing the wind pressure) forces higher harmonics to supersede the fundamental pitch. A bugler, whose instrument is a tube of constant length, can thus play tunes by overblowing to produce various harmonics. Brasses of unvariable sounding length are called natural; they are limited to the notes of the harmonic series. As composers since the 1500s gradually made greater demands on trumpets and horns (which were originally outdoor signal instruments), instrument makers invented the key and valve mechanisms that enable the instruments to produce fully chromatic scales. Woodwinds, similarly, were fitted with complex key mechanisms. Such structural changes, however, necessarily affected the timbre; modern brasses, as well as keyed woodwinds, sound noticeably different from those of the early 19th century and before.

VII.

Chordophones

Being of more recent origin than idiophones, drums, and winds, the chordophones are not universally distributed; they were virtually unknown in pre-Columbian America (before the 16th century). Chordophones differ widely in structure, but are all thought to have evolved from the archaic musical bow, which resembles a hunting bow and is played like a jew's harp. Because the sound of a vibrating string alone is extremely quiet, strings are almost always coupled to a resonator.

A.

Zithers

In the zither group, the strings stretch side by side over a soundboard or sound box, and, with the exception of the Chinese qin (ch'in), communicate their vibrations to either by means of one or more bridges. The Japanese koto has movable bridges, one for each string. This revered zither, like the bridgeless qin, has an extensive classical repertoire. The Appalachian dulcimer (not the same as the hammered dulcimer) evolved in the late 19th century from northern European fretted zithers brought to America by immigrants. These folk zithers have melody strings passing over a fretted fingerboard, in addition to unfretted accompaniment strings.

B.

Keyboard Chordophones

Two zither-family instruments, the hammered dulcimer (see Dulcimer) and the medieval psaltery, are ancestors of keyboard chordophones such as the piano, clavichord, and harpsichord. The last two instruments were invented in the late Middle Ages (the late 14th and early 15th centuries) in conjunction with the emergence of multipart music. The piano, with its wider dynamic range, appeared about 1700. It largely replaced the hammered dulcimer in urban domestic use, and by 1800 it had superseded the quieter clavichord and harpsichord. The hurdy-gurdy, which is a fiddle with a keyboard of limited compass, has both melody and drone strings, sounded by a rotating circular “bow” of wood. It resembles the Swedish nyckelharpa, a keyed fiddle played with a conventional bow.

C.

Harps and Lyres

Unlike zithers, which may be plucked, bowed, struck, or wind-sounded (the aeolian harp), true harps are almost exclusively plucked. Their many strings fasten directly into the resonator; no bridge is necessary. The frame of European harps consists of a sound box, a neck (called the harmonic curve), and a forepillar, roughly forming a triangle. Ancestral, non-Western harps such as the Myanmar saung lack the reinforcing forepillar; their angled or arched necks, therefore, cannot withstand extreme string tension. The African pluriarc has a separate neck for each string.

A modern concert harp has a pedal mechanism that alters the pitch of each string by one or two semitones, thereby producing a full chromatic compass although having only seven strings per octave. Simpler pedal and manual devices offered chromatic notes in 18th-century harps, but earlier chromatic harps (notably the Welsh telyn) had two or three rows of strings, each chromatic note having its own string. Although most European harps are strung with gut or synthetic cords, the massive Irish harp traditionally is wire strung. Once favored to accompany bards, the Irish harp became a patriotic symbol when its use was outlawed by English authorities. See Harp.

On lyres, the strings are anchored to a crossbar supported by two arms that extend from a box- or bowl-shaped resonator; they are coupled to the resonator by a bridge. Lyres are rare today outside Ethiopia; however, the Greek ancestor of the Ethiopian lyre was a popular instrument. The kithara was a large, wood-bodied concert lyre of ancient Greece; derivatives of its name were given to unrelated instruments such as the cittern and guitar. See Lyre.

D.

Plucked and Bowed Lutes

The European lute is the namesake of a group of bowed and plucked instruments (see Lute). Their strings pass along a neck that extends from the resonator, and a bridge couples the strings to the resonator. The neck may be a short elongation of the body, as in the Chinese pipa; or it may be a separate element fastened to or piercing the body. Frequently, the neck incorporates a fingerboard (which may be fretted), against which the strings can be pressed to alter their sounding length.

Plucked lutes include the banjo and guitar as well as the pear-shaped Arabic 'ud, from which the name of the European lute is derived. The technique of bowing is not so old as that of plucking, and fiddles, or bowed lutes (such as the violin and viol) arrived in Europe from Asia only in the Middle Ages. Early European bowed lutes are hardly distinguishable from plucked ones. Evidence of medieval types is limited to fragmentary remains, literary descriptions, and pictures—practically no complete examples survive, due to the instruments' fragility. Comparison with similar-looking modern folk instruments suggests that the latter have changed little since the Middle Ages.

The viola, which evolved from unstandardized medieval fiddles, is first depicted in early 16th-century pictures. Like most other instruments of the Renaissance, it was built in a range of sizes that, together, made up a consort. Small violas (violins), large ones held between the knees (violoncellos; see Cello), and even larger ones played standing up (violones) were the specialty of Italian artisans such as the Amati family and Antonio Stradivari. The pochette or kit, a miniature violin-type instrument played by dancing masters, often had a one-piece body and neck carved from a block of wood; it thus resembled the medieval rebec, the name and shape of which were in turn derived from the Middle Eastern rabab.

The violin and its relatives—at first associated with country dance music and considered inferior to the quieter, more sedate viola da gamba (viol)—became supreme during the 18th century (and earlier in Italy) because viols were less well suited to the highly dramatic style of late baroque and classical music. When the intimate idiom of the classical era gave way to the 19th-century romantic style, violins and most other orchestral instruments were modified to increase their compass and dynamic range. Loudness and brilliance became necessary because of the introduction of large concert halls and the virtuosic demands of romantic composers and performers.

Among the interesting hybrid chordophones are the baryton, a viol equipped with additional thumb-plucked wire strings; and the arpeggione, a cello-sized bowed guitar briefly popular in the 1830s. The viola d'amore, still called for by a few 20th-century composers, has unfingered strings that vibrate sympathetically beneath the bowed ones, giving an especially warm tone. Sympathetic strings are found also in many Asian chordophones, particularly in India, where the gourd-bodied sitar is a favorite vehicle for classical improvisation. West African plucked instruments such as the kora (harp-lute) and the muet (harp-zither) combine features of harps, lutes, and zithers.

VIII.

Electrophones

Just as mechanical invention served European music when the fully developed keyboard (a device uniquely associated with Western technology) arose in the late Middle Ages, so electrical engineers have offered 20th-century musicians an innovative means of producing and controlling sounds. The telharmonium, an electrophone created by the American inventor Thaddeus Cahill at the turn of the century, produced novel tones with a collection of equipment that included rotary generators and telephone receivers. The theremin, a compact apparatus invented by the Russian physicist Leon Theremin, was fashionable in the late 1920s and 1930s, although it could play only a single melodic line. Electronic organs have mainly influenced popular music, but since the mid-1950s synthesizers have become important tools of composers in many idioms (see Electronic Music). Since the 1930s electronic amplification has tremendously increased the impact and altered the technique of popular singers and instrumentalists. In the electric guitar such amplification replaced the sound box and stimulated new musical effects. Except in the distortions and manipulations of sound used in rock music, however, amplification, like broadcasting and recording, serves chiefly to disseminate music rather than to create it. The long-term implications of electronic sound production cannot yet be predicted.