Mechanisms that open and close the swell box valves to control volume; the swell box houses the pipes of one or more manuals.
toe piston
Mechanism controlled by foot that prepares the pipes in advance, making them sound only when the pedal is pushed.
thumb piston
Hand-controlled mechanism used to prepare the pipes of a manual in advance, making them sound only when the piston is pushed.
manuals
Each of the series of keys that the organist plays by hand, which control one or several pipes of the same note.
coupler-tilt tablet
Plate that controls the mechanism joining two or more manuals.
pedal keyboard
Series of keys that the organist operates by foot.
pedal key
Lever that is lowered using the foot to allow air to enter and produce sound.
crescendo pedal
Pedal mechanism allowing certain combinations of pipes to sound and increasing their number until "e&tutti"e&, when all pipes are heard.
great organ manual
Series of keys that make up the main keyboard, which is used to play the most important parts.
choir organ manual
Keyboard that controls a series of pipes at the front of the organ; its timbres are softer than those of the great organ.
swell organ manual
Keyboard that controls a series of pipes enclosed in a wooden frame (swell box); its movable valves are controlled by a swell pedal to obtain variations in volume.
stop knob
Device attached to a stop rod that controls the slider, which allows a row of pipes to sound or remain silent.
