Musical Instruments

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).

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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.

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