INSTRUMENTATION

also called orchestration in music, arrangement or composition for instruments. Most authorities make little distinction between the words instrumentation and orchestration. Both deal with musical instruments and their capabilities of producing various timbres or colours. Orchestration is somewhat the narrower term since it is frequently used to describe the art of instrumentation as related to the symphony orchestra. Instrumentation, therefore, is the art of combining instruments in any sort of musical composition, including such diverse elements as the numerous combinations used in chamber groups, jazz bands, rock ensembles, ensembles employing chorus, symphonic bands, and, of course, the symphony orchestra. Included under this designation are the various instrumental groups that play non-Western music, such as the gamelan orchestras of Bali and Java and the traditional ensembles of India, Africa, the Far East, and the Middle East. (For treatment of the instruments themselves, see the articles musical instrument, percussion instrument, stringed instrument, keyboard instrument, wind instrument, and electronic instrument.) In Western music there are many standard or traditional groups. The modern symphony orchestra usually comprises the following instruments, although they are not necessarily used in every composition: 1. Woodwinds: four flutes (one doubling, or duplicating the part of the piccolo), four oboes, English horn (cor anglais), three clarinets, bass clarinet, three bassoons, contrabassoon (double bassoon); 2. Brass: four trumpets, four or five French horns, three trombones, tuba; 3. Strings: two harps, first and second violins, violas, violoncellos, double basses; 4. Percussion; four timpani (played by one player) and at least three general percussion players. The orchestra has arrived at this complement through centuries of evolution; the present size is needed to perform repertoire from the Baroque, Classical, Romantic, and Impressionistic periods, as well as the repertoire of the 20th century. The various sections, with the exception of percussion, divide themselves in somewhat the same manner as a choir. The woodwinds, for example, divide into flutes (sopranos), oboes (altos), clarinets (tenors), and bassoons (basses), although this distinction must be greatly qualified. Instrumental range is larger than vocal range, and the clarinets of an orchestra may play higher than the flutes in a woodwind passage. The standard instrumental groups of Western chamber music include the string quartet (two violins, viola, and violoncello), the woodwind quintet (flute, oboe, clarinet, French horn, and bassoon), the combinations employed in sonatas (one wind or stringed instrument with piano), and the brass quintet (frequently two trumpets, French horn, trombone, and tuba). In addition to these standard groups there are, however, hundreds of other possible combinations. Other groups that deserve mention are those used in the popular music of the 20th century. The dance band, popular in the 1930s and 1940s, consisted of five saxophones, four trumpets, four trombones, double bass, piano, guitar, and drums. The basic rock ensemble consists of two electric guitars, electric bass, electronic organ (doubling electric piano), drums, and frequently one or more singers. The concert band, which is particularly popular in North America, consists of mixed wind and percussion players totalling from about 40 to well beyond 100 players. The music of the non-Western world is most frequently performed by groups of chamber music size. In this category would fall the music played by the Javanese gamelan orchestra (consisting mainly of tuned gongs and other metal instruments), Japanese gagaku music (performed on flutes, mouth organs, lutes, drums, and gongs), and Chinese music (with a traceable history of about 4,000 years) consisting of sacred, folk, chamber, and operatic music. also called Orchestration, in music, arrangement or composition of music for instruments. The word orchestration usually indicates music written for an orchestra, and in that sense, it is a narrower term than instrumentation, which can be applied to non-Western musical ensembles as well as to instrumentation for musical groups that are not strictly orchestral. In most cases instrumentation is part of the business of composition, but there are occasions when the two activities are carried out by different performing traditions, as with Wolfgang Amadeus Mozart's arrangement of George Frideric Handel's Messiah, or the orchestral versions of works by Johann Sebastian Bach created in the early part of the 20th century by Sir Edward Elgar, Arnold Schoenberg, and many others. Conductors may also decide to alter the instrumentation of works that they perform, though this practice finds less favour now than it did in earlier times. In the field of light music, however, there is frequently a degree of specialization, with the composer providing the tune, and the arranger the harmony and orchestral colour. The history of instrumentation is inevitably bound up with the history of the orchestra, which had its beginnings in the early part of the 17th century. In his opera Orfeo, Claudio Monteverdi gave suggestions for the use of a large ensemble of bowed string, plucked string, wind, and keyboard instruments, but this was unusual, and he did not indicate the use of the instruments in any detail. His chamber drama Il combattimento di Tancredi e Clorinda (The Combat of Tancredi and Clorinda) is one of the earliest works in which the instrumentation is specified by means of a score, though here for only four lines of strings. Ever since Monteverdi's time the strings have been regarded as the foundation of the orchestra, to which composers in the 18th century often added oboes, bassoons, and horns. Other instruments were reserved generally for particular occasions: trombones to suggest solemnity, for instance, or trumpets and drums to add a martial tone. Toward the end of the 18th century, however, these instruments began to be used more frequently without such associations. The orchestra also grew with the introduction of clarinets. These were specially favoured by Mozart, for instance, whose scoring for wind instruments has not been surpassed. Improvements in instrument design during this same period also increased the flexibility of the wind instruments, and by Ludwig van Beethoven's time the orchestra had achieved the standard composition it still adheres to, with strings in five parts (two of violins, one each of violas, cellos, and double basses) joined by a woodwind family of flutes, oboes, clarinets, and bassoons, a brass group of horns, trumpets, and trombones, and timpani. It is this ensemble that provides the mass effects of Beethoven's Fifth Symphony and the delicacy of his Pastoral Symphony and Franz Schubert's Great Symphony. Further developments were at hand. Carl Maria von Weber began to exploit the possibilities of the orchestra for pictorial imagery and its ability to suggest darkness, woodland scenes, and extremes of weather, especially in his opera Der Freischtz (The Freeshooter). Hector Berlioz emboldened the illustrative manner of Weber and added new instruments to the orchestra for special effectsfor example, the harps, English horn, bells, and other percussion instruments in his Symphonie fantastique. He also wrote one of the first treatises on orchestration. This new awareness of the orchestra's potential was shared by most composers later in the century: particularly Franz Liszt, Richard Wagner, Peter Ilich Tchaikovsky, and Richard Strauss. Others, notably Robert Schumann and Johannes Brahms, have been seen as less successful orchestrators, but only because their music does not, in the main, make a special feature of variety of colour. In truth, the sober gradations of Brahms are as skillful as the vivid tone pictures of Strauss's scoring. It became common practice in the 19th century for composers to write out works in some kind of draft, perhaps for piano, and then orchestrate them later. Many composers in the 20th century, however, have used the orchestra so subtly and variedly that they have needed to compose directly in orchestral score, without any intermediate stage. In this case, instrumentation becomes inextricably part of the act of composition: it would seem to be so, for example, in the music of Claude Debussy. There are others, such as Maurice Ravel and Olivier Messiaen, who have seen instrumentation as quite separate and have even orchestrated works of their own that were originally created for keyboard. If, however, instrumentation is the art of finding new sounds within a fixed body of instruments, arguably the greatest master of it in the 20th century is Igor Stravinsky. in technology, the development and use of precise measuring equipment. Although the sensory organs of the human body can be extremely sensitive and responsive, modern science and technology rely on the development of much more precise measuring and analytical tools for studying, monitoring, or controlling all kinds of phenomena. Some of the earliest instruments of measurement were used in astronomy and navigation. The armillary sphere, the oldest known astronomical instrument, consisted essentially of a skeletal celestial globe whose rings represent the great circles of the heavens. The armillary sphere was known in ancient China; the ancient Greeks were also familiar with it and modified it to produce the astrolabe, which could tell the time or length of day or night as well as measure solar and lunar altitudes. The compass, the earliest instrument for direction finding that did not make reference to the stars, was a striking advance in instrumentation made about the 11th century. The telescope, the primary astronomical instrument, was invented about 1608 by the Dutch optician Hans Lippershey and first used extensively by Galileo. Instrumentation involves both measurement and control functions. An early instrumental control system was the thermostatic furnace developed by the Dutch inventor Cornelius Drebbel (15721634), in which a thermometer controlled the temperature of a furnace by a system of rods and levers. Devices to measure and regulate steam pressure inside a boiler appeared at about the same time. In 1788 the Scotsman James Watt invented a centrifugal governor to maintain the speed of a steam engine at a predetermined rate. Instrumentation developed at a rapid pace in the Industrial Revolution of the 18th and 19th centuries, particularly in the areas of dimensional measurement, electrical measurement, and physical analysis. Manufacturing processes of the time required instruments capable of achieving new standards of linear precision, met in part by the screw micrometer, special models of which could attain a precision of 0.000025 mm (0.000001 inch). The industrial application of electricity required instruments to measure current, voltage, and resistance. Analytical methods, using such instruments as the microscope and the spectroscope, became increasingly important; the latter instrument, which analyzes by wave length the light radiation given off by incandescent substances, began to be used to identify the composition of chemical substances and stars. In the 20th century the growth of modern industry, the introduction of computerization, and the advent of space exploration have spurred still greater development of instrumentation, particularly of electronic devices. Often a transducer, an instrument that changes energy from one form into another (such as the photocell, thermocouple, or microphone) is used to transform a sample of the energy to be measured into electrical impulses that are more easily processed and stored. The introduction of the electronic computer in the 1950s, with its great capacity for information processing and storage, virtually revolutionized methods of instrumentation, for it allowed the simultaneous comparison and analysis of large amounts of information. At much the same time, feedback systems were perfected in which data from instruments monitoring stages of a process are instantaneously evaluated and used to adjust parameters affecting the process. Feedback systems are crucial to the operation of automated processes. Most manufacturing processes rely on instrumentation for monitoring chemical, physical, and environmental properties, as well as the performance of production lines. Instruments to monitor chemical properties include the refractometer, infrared analyzers, chromatographs, and pH sensors. A refractometer measures the bending of a beam of light as it passes from one material to another; such instruments are used, for instance, to determine the composition of sugar solutions or the concentration of tomato paste in catsup. Infrared analyzers can identify substances by the wavelength and amount of infrared radiation that they emit or reflect. Chromatography, a sensitive and swift method of chemical analysis used on extremely tiny samples of a substance, relies on the different rates at which a material will adsorb different types of molecules. The acidity or alkalinity of a solution can be measured by pH sensors. Instruments are also used to measure physical properties of a substance, such as its turbidity, or amount of particulate matter in a solution. Water purification and petroleum-refining processes are monitored by a turbidimeter, which measures how much light of one particular wavelength is absorbed by a solution. The density of a liquid substance is determined by a hydrometer, which measures the buoyancy of an object of known volume immersed in the fluid to be measured. The flow rate of a substance is measured by a turbine flowmeter, in which the revolutions of a freely spinning turbine immersed in a fluid are measured, while the viscosity of a fluid is measured by a number of techniques, including how much it dampens the oscillations of a steel blade. Instruments used in medicine and biomedical research are just as varied as those in industry. Relatively simple medical instruments measure temperature, blood pressure (sphygmomanometer), or lung capacity (spirometer). More complex instruments include the familiar X-ray machines and electroencephalographs and electrocardiographs, which detect electrical signals generated by the brain and heart, respectively. Two of the most complex medical instruments now in use are the CAT (computerized axial tomography) and NMR (nuclear magnetic resonance) scanners, which can visualize body parts in three dimensions. The analysis of tissue samples using highly sophisticated methods of chemical analysis is also important in biomedical research. Additional reading Willi Apel, Harvard Dictionary of Music, 2nd ed. rev. (1969), a good source on any musical subject; Donald Jay Grout, A History of Western Music (1960), the best general history of music to date; Adam Carse, The History of Orchestration (1925, reprinted 1964), a detailed look at the evolution of the orchestra and musical instruments; Nicolas Rimsky-Korsakov, Principles of Orchestration, with Musical Examples Drawn from His Own Works, ed. by Maximilian Steinberg, 1 vol. (1964; orig. pub. in Russian, 1910), still one of the best texts for the serious student; Romain Goldron, Ancient and Oriental Music (1968), examples of non-Western music and instruments.