vox organalis

…another part, “organal voice” (vox organalis), singing the same melody in parallel motion a perfect fourth or fifth below (e.g., G or F below C).

…principalis), a second voice (vox organalis) could be added at the interval (distance between notes) of a fourth or fifth (four or five steps) below. Music so performed was known as organum. While it may be assumed that the first attempts at polyphony involved only parallel motion at a…