Article
David Fuller
(It.: ‘necessary’)
An adjective or noun referring to an essential instrumental part. The term is often used for a part ranking in importance just below the principal melody and not to be omitted. Obbligato is the opposite of Ad libitum when the latter qualifies the mention of a part in a title. On the title-page of Corelli's Concerti Grossi op.6, for example, the concertino parts are designated ‘obligato’ while the ripieno parts are described as ‘ad arbitrio, che si potranno radoppiare’ (as you wish, when you are able to double the parts). Used in connection with a keyboard part in the 18th century, obbligato designated a fully written-out part instead of a figured bass. Sometimes obbligato means simply independent, as in C.P.E. Bach's Orchester Sinfonien mit zwölf obligaten Stimmen (1780).
In music for voice with instruments, ‘obbligato’ refers to a prominent instrumental part in an aria or other number. The archetype of the obbligato part is the instrumental solo which, with a basso continuo, constitutes the accompaniment of vast numbers of late Baroque arias. The direct antecedents of the late Baroque phenomenon are to be found in the ...
Article
Peter Williams and Christopher Kent
Most notably since c 1750, when London publishers began issuing Handel's oratorios in two-stave reductions for solo organ, the term has denoted an abbreviated arrangement of a work for whose original instrumentation the organ stands as substitute. The practice grew in the 19th century, initially through the publications of Vincent Novello, which included organ scores of Haydn's masses. Previously, the term had two more important usages: (i) an open score (very often in four parts) of a piece of organ music, particularly of a serious or contrapuntal nature, from Frescobaldi's ricercares to Bach's Die Kunst der Fuge; (ii) an open score of a vocal or instrumental work accompanied by the organ which reproduces the sung parts. Organ-basses of the 1590s, and hence figured basso continuo parts of the next decade, are as it were shorthand organ scores, indicating harmonies rather than exact parts, though these were considered the ideal realization (Viadana, ...
