Principal (organ)
The open main stop of the organ.
What it means
The principal is the open main stop of the organ and the foundation of its sound. Its pipes are built open, usually of tin or tin-lead, and sound bright, clear, singing and neutral. It occurs at many pitches, such as 16, 8, 4 or 2 foot, and forms the principal family on which mixtures and other stops build.
Musical use
The principal is the "face" of the organ, since its pipes often stand in the case. A chorus of principals at several pitches forms, together with the mixtures, the plenum, the full organ sound. In English the principal corresponds to the diapason, which, unlike the German principal, is sometimes built softer. Because its tone color is neutral, it serves as the basis for registration.
The principal should be distinguished from the prestant, the front principal at 4-foot pitch, from stopped flutes, which sound softer and darker, and from reed stops, which are sharp and pronounced.
Performance practice
As an organist you show the clarity of a polyphonic line with the principal. Play with distinct, even articulation, for the sound of the principals does not cover up inaccuracies.