Laurence Dreyfus: Bach’s Continuo Group – Players and Practices in his Vocal Works (Harvard, 1987)
This excellent book will inform one’s understanding and awareness of the music of Bach. Dreyfus is a musicologist and currently a member of the faculty of Magdalen College, Oxford, and a viola da gambist of repute. He has studied with Bach scholar Christoph Wolff.
The book examines four aspects of Bach’s employment of the continuo, namely,
(1) which keyboard instruments accompanied his sacred vocal compositions,
(2) how were the instrumental parts in recitatives executed,
(3) where were doubling instruments such as the bassoon, ‘cello, and violone used, and,
(4) did the continuo ever include instruments such as the viola da gamba, lute, or violoncello piccolo.
His research is comprehensive and the analysis incisive and illuminating.
In brief, his conclusions are that:
(1) organ and harpsichord provided a dual accompaniment;
(2) in secco recitative, which is supported by the continuo only, the parts were played as quarter notes, that is, in short values despite the notation, but accompagnato recitative, which is supported by other instruments of the ensemble, is played as written;
(3) the bassoon frequently, but also the ‘cello and violone, occasionally, were stipulated as members of the continuo, but from time to time, as the music demanded it, also received independent parts; and,
(4) occasionally, it is plausible that the viola da gamba, lute, or violoncello piccolo were assigned to the continuo.