Chiavette (plural of , ) is a system of standard combinations of clefs used in polyphonic music of the 16th–18th century. One set of clefs sometimes termed chiavi transportate places each staff line a third lower than the usual set of soprano, alto, tenor, and bass clefs, called chiavi naturali. A second set of clefs places each staff line a third higher.
The phenomenon of music appearing in standard clef combinations was first noted by music theorist Giuseppe Paolucci in 1765. Scholars disagree over the meaning of these groupings, but there are two basic views:
- When clefs shift, pitches shift, or
- When clefs shift, vocal ranges shift, but pitches remain the same.
The first view implies that when a note such as C appears in chiavette [high clefs], it should be sung or played a third higher than a C appearing in chiavi naturale. If this view is true, many modern performances of Renaissance polyphony may be at pitches differing significantly from those of the Renaissance.
Eighteenth-century theorists saw in these groupings a system of transposition clefs. This indicated the standard groupings could be used to transpose a piece for an ensemble of a different vocal range by reading a work in a different set of clefs. For example, a piece written in high clefs for a choir of men and boys could be performed by a men-only ensemble at a pitch a fifth lower by imagining the contrabasso set of clefs. This requires imagining a change of key signature.