Listed only by Audsley. In The Art of Organ Building he says: The name that may be appropriately given to a string-toned labial stop which has a voice less pronounced than the Violoncello, 8 ft., and which may be accepted as imitative of the old Bass Viol, the largest and deepest of the �chest of Viols.� In his Organ Stops and their Artistic Registration, Audsley also states that it is made of metal. He implies that no such stop actually exists, but see examples below.
Bass Viol 8', Pedal; Victor Talking Machine Co. Studio (formerly Trinity Church), Camden, New Jersey, USA; Estey 1926.