A term applied to Baroque sonatas for two or three melody instruments and continuo. Many trio sonatas are for strings, but wind instruments (cornetto, oboe, flute, recorder, bassoon) are also found. The melodic parts are usually of equal importance, although the bass may be less active. Trio sonatas were perhaps the most popular instrumental music of the period, written by composers throughout Europe and eagerly consumed, especially by amateurs. Their three-part texture could also be rendered by a single melodic instrument and obbligato keyboard, and some sonatas exist in both formats; Bach’s organ trios (bwv525–30) demonstrate the transfer of the idiom to two manuals and pedal.
In the 17th century, Italian church sonatas a due and a tre were composed for two (ss, bb, sb) or three (ssb, sbb and sss) instruments and continuo; melodic bass instruments participated fully in the contrapuntal dialogue, which was simplified in the chordal continuo. From Rossi to Corelli secular trios ordinarily had a single bass part, played by a chordal or melodic instrument (chitarrone in Rossi’s trios, bowed string in Buonamente’s). Corelli’s sonatas conform to this pattern, opp.1 and 3 requiring four instruments (two violins, violone or archlute, and organ), opp.2 and 4 needing only three (two violins and violone or harpsichord). After 1700, most English and Dutch editions treated church and chamber sonatas identically; thus Roger’s version of Corelli’s op.2 has four partbooks (two identical ones for the bass) and is entitled Suonate da camera à tre, due violini e violone, col basso per l’organo (Amsterdam, c1706).
From the late 17th century, composers strongly favoured scorings for two treble instruments, with or without bass; moreover, melodic bass and continuo were less and less independent, although Buxtehude still wrote virtuoso sonatas for violin, bass and continuo. In his description of the trio and quartet, Quantz recognized the dual function of the continuo bass (it must participate fully in any fugal passages, yet must have a true bass quality) and included it as he counted the parts (Versuch, 1752, chap.18). Thus, his quartet is identical with the earlier trio for three treble instruments, or two treble and one bass, with continuo. Similarly, Quantz’s trio has two principal parts and continuo, just like the earlier sonata a 2.
See also Sonata, §II.
C. Hogwood: The Trio Sonata (London, 1979)
N.M. Jensen: ‘The Performance of Corelli’s Chamber Music Reconsidered: some Characteristics of Structure and Performance in Italian Sonatas for One, Two and Three Voices in the Decades Preceding Corelli’, Nuovissimi studi corelliani: Fusignano 1980, 241–9
S. Mangsen: ‘The Trio Sonata in Pre-Corellian Prints: When Does 3=4?’, Performance Practice Review, iii (1990), 138–64
P. Allsop: The Italian ‘Trio’ Sonata (Oxford, 1992)
S. Mangsen: ‘The Dissemination of Pre-Corellian Duo and Trio Sonatas in Manuscript and Printed Sources: a Preliminary Report’, The Dissemination of Music, ed. H. Lenneberg (New York, 1994), 71–105
SANDRA MANGSEN