Duet
A vocal or instrumental piece for two voices.
What it means
A duet is a piece for two voices, with or without accompaniment. In the vocal field the term usually means two singing voices with accompaniment; for two instruments without accompaniment the designation duo is also in use, although the words are not used strictly apart. Decisive is two-part writing as the basis of the layout: two equal lines meet, alternate, join, and part again.
Musical use
In opera the duet carries the encounter of two characters and forms one of the most important number types; musically the roles are mirrored in whether the voices are led one after another, simultaneously, in thirds, or in opposition. In church music duets appear as movements for two soloists over continuo. In teaching the instrumental duo has a fixed place, because ensemble playing, intonation, and rhythm can be experienced directly there. Musically, two-part writing is demanding, since every inaccuracy is audible at once and nothing can be covered.
In opera, love duets and confrontation duets are among the high points, in Mozart, Verdi, and Puccini as well as in the musical.
Performance practice
Settle beforehand who leads in which section, and adapt articulation, phrasing, and vibrato to each other; differing conceptions stand out immediately in two voices. Practise parallel thirds and sixths separately for intonation, because they are particularly sensitive. Breathe together at entries and agree signals. While playing, listen more to your partner than to yourself. Sit or stand so that you hear each other well, and rehearse the balance in the performance space.
Bear in mind that in a vocal duet the treatment of the text must be settled together: consonants, distribution of syllables, and breathing places should agree, otherwise the texture falls apart. Speak the text together before you sing. Settle who leads in which section, and adapt vibrato and tone colour to each other.
Settle beforehand who determines the moment of release at free endings.
Also check whether an edition is available in several keys so that both voices lie comfortably.