Bach Cantata - Singers and Instrumentation

Singers and Instrumentation

Typically Bach employs soprano, alto, tenor and bass soloists and a four-part choir, also SATB. Singers of all parts were available without restriction, therefore he could assign the voice parts to the dramatic situation, for example soprano for innocence or alto for motherly feelings. The bass is often the vox Christi, the voice of Jesus, when Jesus is quoted directly, as in Es wartet alles auf dich, BWV 187, or indirectly, as in O Ewigkeit, du Donnerwort, BWV 60.

The orchestra is based on string instruments (violin, viola) and basso continuo, typically played by cello, double bass (an octave lower) and organ. A continuous bass is the rule in Baroque music, its absence is worth mentioning and has a reason, such as describing fragility.

The specific character of a cantata or a single movement is rather defined by wind instruments, such as oboe, oboe da caccia, oboe d'amore, flauto traverso, recorder, trumpet, horn, trombone, and timpani. In movements with winds a bassoon usually joins the continuo group.

Festive occasions call for richer instrumentation. Some instruments also carry symbolic meaning such as a trumpet, the royal instrument of the baroque, for divine majesty, three trumpets for the Trinity. In an aria of BWV 172, addressing the "Heiligste Dreifaltigkeit" (Most holy Trinity), the bass is accompanied only by three trumpets and timpani.

In many arias Bach uses obbligato instruments, which correspond with the singer as an equal partner. These instrumental parts are frequently set in virtuoso repetitive patterns called figuration. Instruments include, in addition to the ones mentioned, flauto piccolo (sopranino recorder), violino piccolo, viola d'amore, violoncello piccolo (a smaller cello), tromba da tirarsi (slide trumpet), and corno da tirarsi.

In his early compositions Bach also used instruments that had become old-fashioned, such as viola da gamba and violone. Recorders (flauti dolci) are sometimes used to express humility or poverty, such as in the cantata Brich dem Hungrigen dein Brot, BWV 39.