Hypophrygian

What it means

Hypophrygian is the plagal form of the Phrygian mode and counts as the fourth church mode. The scale consists of the same notes as the Phrygian, but the range in which a melody moves lies a fourth lower than in the authentic Phrygian mode, while the final stays the same.

Musical use

As with all plagal modes, the prefix “hypo-” marks the lower-set melodic range: the authentic Phrygian mode moves from the final upward over an octave, the Hypophrygian from a fourth below it to a fifth above. Hypophrygian shares the final with authentic Phrygian and, in modified form, the reciting tone, but differs in ambitus.

Hypophrygian should be distinguished from authentic Phrygian, with which it shares the final and pitch material, and from Hypodorian, the plagal form of the Dorian mode with a different final. Both plagal forms lie tonally close and are easily confused if only the key signature, not the final, is heeded.

Performance practice

Determine the mode of a Gregorian melody first by the closing note and then by the ambitus, to distinguish authentic from plagal form. Sing Hypophrygian melodies calmly and connectedly, aware of their lower range, without losing the characteristic semitone step above the final that gives the Phrygian mode its distinctive sound.