Tremulant (Fr. Tremblant; It. Tremolo; Sp. Temblor)
- Barbara Owen
(Fr. Tremblant; It. Tremolo; Sp. Temblor)
An important accessory stop found in organs of all sizes since the early 16th century, although it is not always mentioned in early contracts, and is sometimes referred to by other names (e.g. ‘shaking stop’ in Tudor England). By slightly disturbing the wind supply, it causes an undulating or tremolando effect in the music, somewhat like a vocal vibrato. Two types were known to 17th and 18th century organ builders, and it is not known which is of the greater antiquity. The external tremulant (tremblant fort, tremblant à vent perdu, Bocktremulant; see fig.1a) consists of a balanced and adjustable sprung valve which allows intermittent pulses of wind to escape. The internal tremulant (tremblant doux, Schwebung; see fig.1b) consists of a sprung and weighted flap or gate within a wind-trunk, which momentarily interrupts the flow of wind to the chest. Unlike the external tremulant, the internal type is affected by the flow of wind, and behaves differently when a large or small number of stops is drawn. When not in use, the plate of the internal tremulant is pushed up against the side of the wind-trunk, and the bellows of the external tremulant is fixed in a closed position. As the names imply, the external tremulant produced a stronger and less subtle effect than the internal type....