A pedal mutation stop of 10-2/3' pitch. It has been made in a variety of forms: wood or metal, open or stopped. Irwin reports that it is usually of Diapason tone; Audsley says that open pipes �are to be desired in all cases�. This stop reinforces the 32' harmonic series, but it often appears in a pedal division that has no 32' stops: when drawn with a 16' stop, it produces a resultant 32' tone (see Resultant). For other synonyms, see Fifth.