swell box
English composer
Definition
An enclosure around one or more divisions of the organ with shutters (jalousies) that open and close via a pedal, allowing dynamic gradation not otherwise possible on the organ.
Interpretive Guidance
Franck exploits the swell box more systematically than any composer before him. In the Chorals and Trois Pièces, long crescendos are made by progressively opening the swell box while adding stops. The movement of the shutters should be smooth and continuous, not stepwise. On instruments with a single swell division, careful planning is needed to preserve the dynamic architecture of each piece.