Plagal cadence

What it means

The plagal cadence is the closing turn from the subdominant to the tonic, S–T (IV–I). It is the harmonic umbrella term for this turn; when it is sung at the end of a chorale to the syllables of “Amen,” one speaks of the Amen cadence.

Musical use

What is characteristic is what is missing: the leading tone. In the authentic close, the third of the dominant rises as a leading tone to the tonic, and the tritone of the D7 resolves. In the plagal cadence this tension does not exist. The root of the tonic is already contained in the subdominant as the fifth and stays put, while the other voices sink stepwise into the tonic. The result is a soft, confirming close without goal-directed force.

From this its usual position follows: it often follows an already reached authentic close as an additional confirmation, as it were an afterword. As the sole close of a larger movement, by contrast, it often seems too weak. Outside church music the turn is widespread in gospel, soul, and large parts of popular music, where it serves as a calm fade-out; there the minor subdominant also stands before a major tonic, which gives the close a particular colouring.

The plagal cadence is to be distinguished from the authentic close, which leads to the tonic with a leading tone, and from the half cadence, which remains open on the dominant. It shares only the name with the plagal church mode.

Other names

The adjective plagal has two meanings that are to be kept apart: in cadence theory it means the turn subdominant–tonic, in the theory of the church modes the form of a mode whose tonal space reaches below the finalis (see plagal mode). Both go back to the same Greek word but designate different matters.

Performance practice

Pull the tonic sonority back dynamically at the end and let the subdominant sonority stand broader — the turn lives from the calm sinking. Keep the shared note calm. And shape the plagal cadence after an authentic close as an echo, not as a new climax.