The mechanism which admits wind to the pipes at the correct moment, responding to the organist’s inputs at the console.
The lowest notes of a particular stop are sometimes referred to as the “basses”
A large turbine, powered by an electric motor, which produces a large amount of pressurised air for the organ.
The large timber structure upon which the organ components are mounted.
Case / Casework
The decorated enclosure which covers the openings to the organ chamber.
A rank of pipes intentionally tuned sharp or flat to produce an undulating effect.
Originally installed as the Chancel Great department, this section of the organ speaks directly into the chancel, housed in a case added in 1896. As the name suggests, this department is used as an alternative to the Great when accompanying the choir. It also functions as a secondary Great department when accompanying hymns or repertoire.
The system by which Thumb and Toe Pistons can be programmed and used to rapidly change registration (or “combinations”) during performance.
The collection of stops, keyboards and other controls which the organist uses to control the organ.
A device which allows one or more departments to be played simultaneously from one keyboard. The couplers work in one direction, rather than both; that is to say that if the Swell to Great coupler is drawn, both departments will play from the Great keyboard, but only the Swell department will play from the Swell keyboard.
A specific section of the organ, controlled by its own keyboard.
The mechanism that translates the operation of Stops at the console into movement of the appropriate slider.
A large wooden box within which pipework is located. One side of this box is fitted with shutters, in the manner of a venetian blind, which can be opened or closed by the organist.
This pedal is connected to the shutters on the front of the Expression Box. Closing the shutters traps the sound within the box, providing dynamic control over the sound produced.
The most common type of organ pipe, which produces sound in a similar manner to a recorder, by blowing air across the top lip, causing the column of air within the body of the pipe to vibrate.
The department housed in within the main case, speaking into the north transept. This department contains a bold diapason chorus, together with a pair of open flutes. In 1899 a reed stop was added to the Great, originally named Euphonium, now the Tromba stop, also available on the Solo and Pedal departments.
The mechanism which controls the flow of air to the pipes as the keys are depressed.
The keyboards for the hands.
A stop consisting of more than one rank of pipes.
The “valve” which corresponds to a particular note on the keyboard. When it is opened, air from the Pallet Box is allowed into the space above and, depending on which Stops are drawn, is admitted to the correct pipes.
The keyboard for the feet.
The department controlled by the organist’s feet. The largest pipes, producing the lowest notes, within the organ belong to this department.
A set of pipes, one per note. Some stops, such as Mixtures, consist of several ranks, with multiple pipes for each note.
A pipe that produces sound through the vibration of a tongue against a shallot.
A large wooden box with a floating top, which both stores the wind ready for use by the pipes, and also sets the output pressure. Incoming wind pressure from the blower lifts the top of the reservoir. Weights placed on the top help to regulate the output pressure. As the organist plays, the top of the reservoir drops, maintaining the correct pressure.
A brass tube located in the bottom of a reed pipe, against which the tongue vibrates.
A piece of wood (or synthetic material) with holes which, when the relevant Stop is drawn, line up with the bottom of the pipe and allow wind to reach it.
The department containing solo sounds, some of which imitate orchestral instruments. These stops are contained within a Swell Box which provides a greater dynamic range.
The large wooden structure on which the pipes stand, containing mechanisms which admit wind to the pipes. See also Windchest
Each “stop”, when drawn, allows wind to reach the pipes associated with that stop, when keys are depressed. The organist uses the stops to create the desired sound.
See Expression Box.
This department is contained within a Swell Box, and contains a wide variety of tone colours. This variety, and the dynamic range possible by moving the shutters on the front of the box, mean that this department is invaluable in accompaniment and the performance of romantic repertoire.
See Expression Pedal.
A control located beneath the keyboard which allows the organist to change the combination of stops without lifting his/her hands from the keys. These can be pre-programmed and used whilst playing for rapid changes of registration.
Similar to a Thumb Piston, but larger and mounted above the pedalboard, for use by the organist’s feet.
A thin strip of brass which vibrates, producing the sound in reed pipes.
The electronic system which translates the inputs from the organist at the console into the necessary outputs to the action.
A device which imparts instability to the wind supply, creating a vibrato effect.
The ducts, usually constructed of wood, but sometimes of metal, which convey wind from one part of the organ to another.
The process of adjusting the pitch of each pipe in the organ so that they all sound “in tune” with each other.
The top layer of the windchest/soundboard upon which the pipes stand.
The mechanism which opens the Pallets within the Soundboard as the organist plays.
The process of adjusting the various parts of a pipe in order to produce the desired tone.
The pressurised air produced by the Blower.
A mechanism for admitting wind to selected pipes. The chest contains wind under pressure. Often, the term “Chest” or “Windchest” is used to differentiate between a Slider-Soundboard, which uses pallets and sliders to control the flow of wind, and a “sliderless” chest, which has individual pallets for each pipe.
Sliderless chests are often used for the basses of stops which would otherwise be too large to fit on the soundboard. Chests are also used for stops that are voiced on a higher wind pressure than other ranks in the organ, such as the Trombone, Tromba and Tuba Mirabilis.