synthesizer, musical: see electronic music.

musical notation, symbols used to make a written record of musical sounds.

Two different systems of letters were used to write down the instrumental and the vocal music of ancient Greece. In his five textbooks on music theory Boethius (c.A.D. 470-A.D. 525) applied the first 15 letters of the alphabet to the notes in use at the end of the Roman period. Notation of Gregorian chant was by means of neumes, which are thought to have been derived from symbols used in the Greek language to indicate pitch inflection. Neumes were certainly in use by the 6th cent., although the earliest extant manuscripts containing them are fragmentary ones from the 8th cent. These neumes indicated only the grouping of sounds in a given melody, evidently to recall to a singer the approximate shape of a melody already learned by ear.

Heighted neumes, arranged above and below a line, made the intervals of a melody more discernible in 10th-century notation, and by the end of the 12th cent. the staff perfected by Guido d'Arezzo was in use. Guido placed letters on certain lines to indicate their pitch, and thereby the pitch of the remaining lines and spaces. The letters evolved into the clef signs used today. Guido also invented a system of naming scale degrees using the initial syllables of the lines of a Latin hymn (ut, re, mi, fa, sol, la). Originally used for teaching sight singing, these or their derivatives are also used in some languages for naming absolute pitches.

A staff of five lines for vocal music was adopted in France and one of six lines in Italy. Instrumental music employed staves of varying numbers of lines until the 16th cent., when the five-line staff became the standard. Signs for chromatic alteration of tones appear almost from the beginning and had assumed their present shapes by the end of the 17th cent. The essential problems in pitch notation, the use of both lines and spaces to indicate successive scale degrees and the use of extra symbols to indicate raising or lowering a tone by a half step, were solved comparatively rapidly.

However, the evolution of the rhythmic notation used today took much longer than that for pitch. Mensural notation, in which each note has a specific time value, became a necessity with the development of polyphony. At first, certain patternings of neumes were used to represent the various rhythmic modes; later, in his Ars cantus mensurabilis (c.1280), Franco of Cologne created a clear indication for each note of its exact rhythmic length and selected certain neumes to represent tones of long and short duration. In his system, the long value was in principle equal to three of the short values.

In the 14th cent. Philippe de Vitry, author of Ars nova, which expands the system of Franco, codified the ready availability of duple divisions of the long and short notes. At the various rhythmic levels of a given piece either a 2:1 or a 3:1 relationship was implied, and a system of signs and colored notes developed for indicating which relationships were in force or were being temporarily altered.

In the 15th cent. numbers with the appearance of fractions indicated that one proportionality of rhythmic values was temporarily being substituted for another. Modern signatures evolved from these numbers. Bar lines, expression signs, and Italian terms to indicate tempo and dynamics came into use in the 17th cent. With the adoption of equal temperament and the major and minor modes, signatures indicating a major key or its relative minor became conventional. They assumed their present form during the baroque period.

The advent of aleatory music has produced notation systems, varying from piece to piece, indicating only approximate pitch, duration, and dynamic relations. Notation for electronic music is still not standardized but generally uses traditional reference symbols (staff and clef signs) in conjunction with specially adapted pitch and rhythm notation.

For a system of notation of lute and keyboard music, see tablature. See also score.

musical instruments are classified in various ways, but the system devised in 1914 by Kurt Sachs and E. M. von Hornbostel has been accorded recognition by both anthropologists and musicologists because it is applicable not only to modern Western instruments but to primitive and exotic instruments as well. This system divides instruments into five main classes: idiophones, membranophones, aerophones, chordophones, and electrophones. Most idiophones, which are instruments made of a sonorous material needing no additional tension, and membranophones, whose sound is produced by the vibrations of a membrane stretched over a hollow resonator, are popularly grouped as percussion instruments; certain instruments, however, such as the jew's-harp and the glass harmonica (see harmonica 2), are idiophones, but are not percussion instruments. Aerophones are of two types: free aerophones, which include those reed instruments employing free reeds, and wind instruments, which produce sound by means of an enclosed, vibrating column of air. Chordophones are stringed instruments. Electrophones, a development of the 20th cent., are of two types: those which simply add an electric amplifier to some existing instrument, e.g., the piano, guitar, or reed organ, and those whose sounds originate as electrical vibrations, e.g., the electric organ. See articles on individual instruments, e.g., dulcimer.

musical glasses: see harmonica 2.

musical comedy: see musicals.

In music, position of a single sound in the complete range of sound; this quality varies with the number of vibrations per second (hertz, Hz) of the sounding body and is perceived as highness or lowness. A higher pitch has a higher number of vibrations. In Western music, standard pitches have long been used to facilitate tuning. A confusing variety of pitches prevailed until the 19th century, when the continual rise in pitch made some international agreement a matter of practical necessity. In 1939 the A above middle C was standardized as 440 Hz. Seealso interval; tuning and temperament.

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Written, printed, or other visual representation of music. There are two basic approaches to notating music. Tablature (such as guitar chord diagrams) depicts the actions a performer is to take (in particular, showing where to put the fingers to produce a given sound). Symbolic notation describes the sounds themselves and includes methods that vary from assigning pitches different letters of the alphabet to representing a given combination of notes by a graphic sign. The Western notation system combines rhythmic notation (the appearance of a note indicates its duration) with pitch notation (the line or space on a staff where a note is placed indicates its pitch). Thus, a single symbol shows both pitch and duration, and a string of these symbols notates both melody and rhythm.

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Mechanical musical instrument in which projecting pins on a revolving brass cylinder or disk, encoding a piece of music, pluck tuned steel tongues. It was probably invented circa 1780 in Switzerland. With its modular cylinders or disks, it was a popular domestic instrument until displaced by the player piano and phonograph.

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In chemistry and physics, a theoretical model describing the states of electrons in solid materials, which can have energy values only within certain specific ranges, called bands. Ranges of energy between two allowed bands are called forbidden bands. As electrons in an atom move from one energy level to another, so can electrons in a solid move from an energy level in one band to another in the same band or in another band. The band theory accounts for many of the electrical and thermal properties of solids and forms the basis of the technology of devices such as semiconductors, heating elements, and capacitors (see capacitance).

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Musical ensemble that generally excludes stringed instruments. Ensembles of woodwind, brass, and percussion instruments originated in 15th-century Germany, taking on a particularly military role; these spread to France, Britain, and eventually the New World. In the 15th–18th centuries, many European towns had town musicians, or waits, who performed especially for ceremonial occasions in wind bands often consisting primarily of shawms and sackbuts (trombones). In the 18th–19th centuries, the English amateur brass band, largely consisting of the many newly developed brass instruments, took on the important nonmilitary function of representing organizations of all kinds. In the U.S., Patrick Gilmore's virtuoso band became famous in the mid-19th century; his greatest successor, John Philip Sousa, bequeathed a repertory of marches that has remained very popular. The “big band,” under leaders such as Duke Ellington and Count Basie, was central to American popular music in the 1930s and '40s. In the rock band, unlike most other bands, stringed instruments (electric guitars and electric bass) are paramount.

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or musical comedy

Theatrical production that is characteristically sentimental and amusing in nature, having a simple but distinctive plot and offering music, dancing, and dialogue. Its roots can be traced to 18th- and 19th-century genres such as ballad opera, singspiel, and opéra comique. The Black Crook (1866), often called the first musical comedy, attracted patrons of opera and serious drama as well as those of burlesque shows. European composers such as Sigmund Romberg brought to the U.S. a form of operetta that was the generic source for musical comedy. George M. Cohan ushered in the genre's heyday, and in the 1920s and '30s it entered its richest period with the works of Jerome Kern, George Gershwin and Ira Gershwin, Cole Porter, Richard Rodgers, and Oscar Hammerstein. Kern and Hammerstein's Show Boat (1927) was perhaps the first musical to employ music thoroughly integrated with the narrative. The genre flourished in the 1950s with works by composers such as Leonard Bernstein, but it began to decline in the late 1960s, by which time musicals had begun to diverge in many different directions, incorporating elements such as rock music, operatic styling, extravagant lighting and staging, social comment, nostalgia, and pure spectacle. Later notable musical composers included Stephen Sondheim and Andrew Lloyd Webber.

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