Dictionary of Music - Birding America

theme and variations 427G A B C. The ancient Greeks constructed a scalebased on a tetrachord; theirs also consisted of wholetone, whole tone, half tone, but in descending order,from high to low pitch (for example, A G F E).2 A four-note scale, or, in serial music, four pitchclasses.text Also, lyrics. In vocal music, the words. Atext need not consist of whole words; it may consistof nonsense or other syllables (solmization,vocalization).texture The relationships among the various notesin a musical composition, both as they soundtogether (vertical texture) and one after another(horizontal texture). Vertical texture refers to thechords formed by individual notes—in other words,the harmony. Horizontal texture refers to themelodies formed by the notes in succession, notonly in the main voice-part but in all the voice-parts.It may also refer to the progression of chords, oneafter another. Music in which several voice-partshave more or less equal importance is said to have acontrapuntal or polyphonic texture. Music consistingof a melody in one voice-part accompaniedby chords in the other voice-parts is said to have ahomophonic or chordal texture. Most music withmore than one voice-part falls somewhere betweenthese two extremes. (See also COUNTERPOINT;HOMOPHONY; POLYPHONY.)The term “texture” is also used to describe theinstrumentation of a composition. A piece using fewinstruments or instruments of light tone color (withfew harmonics, such as the flute) is said to have alight texture, whereas a piece using many instrumentsor some with heavy tone color (many harmonics)is said to have a dense or heavy texture.theater orchestra Also, pit orchestra. An ensemblethat plays in the pit for musicals, ballets, andsimilar productions. It generally consists of no morethan two dozen instrumentalists.theater organ A kind of organ used to supplybackground music for silent motion pictures. It waswidely used in the United States from about 1918until the development of motion-picture soundtracksin the late 1920s. The theater organ was a pipe organ(see ORGAN), often very large, with many stops andspecial effects, including a variety of percussion(bass drum, cymbals, xylophone, etc.). Sometimesan entire grand piano was incorporated into theinstrument.thematic catalog An index of compositions thatlists them by their opening notes or principalthemes. These may be represented by standard musicalnotation, or by letters or numbers, or by computercodes. Scholarly thematic catalogs includethose of Köchel for Mozart, Deutsch for Schubert,and Hoboken for Haydn.themeAnother word for SUBJECT.theme and variations An important musicalform, consisting of a subject and a series of variationson it (different versions of the subject). Thevariations may differ from the theme with regard toharmony, melody, rhythm, form, texture, key, mode,meter, or tempo—in short, in any aspect whatever—alone, or in combination. In analyzing a compositionin this form, it is customary to designate the subjectas A and the variations as A′,A′′,A′′′, etc., dependingon the number of variations. A theme and variationsmay be part of a larger work, such as a movementof a sonata or symphony, or it may be anindependent piece. The theme may be a melody, asin Beethoven’s Diabelli Variations, op. 120, or itmay simply be a pattern of bass harmonies a fewmeasures long (as in the CHACONNE, FOLIA, PAS-SACAGLIA, ROMANESCA, etc.).The form of theme and variations first becomepopular during the sixteenth century, with notableexamples found in various English dances for keyboardinstruments (especially for virginal) or forchamber ensembles (consorts of viols), as well as inSpanish music for organ and other instruments(especially diferencias; see DIFERENCIA) by LuisNarváez, Antonio de Cabezón, and others. Duringthe baroque period (1600–1750) the tradition wascontinued in keyboard partitas (by Frescobaldi,Froberger, and others) and in numerous variationson Lutheran hymns (chorales) by German composers.In the classical period (1785–1820) Haydn,