The Organ
Definitions, superlatives and structure

Material based on an interactive talk given by Neil Hawes in 1998 to raise money for the reburbishment of the organ at St Mary's, Osterley.
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The item described in each box “belongs to” and “is contained in” the item in the box above
Organ Console
The “control panel”, built around the possible movements of a person.
One, occasionally two in large buildings

If two, one is the “master” console and one a “secondary” smaller one which might be movable.
Contains manuals, groups of stops, pistons and piston setters, music desk and seat
Also lights for visibility, signal light and wing mirror (Mirror, Signal, Manoeuvre!)
A single keyboard on a console
At least one, two or three is common, up to five on large instruments
plus pedalboard (nearly always)

If more than one console, master console has all the manuals, secondary has some of them
Names: Great, Swell, Choir, Solo, Echo, etc. which partially indicates typical usage
Each manual has a set of keys, usually 61 (5 octaves), for a keyboard
or 30 notes (2.5 octaves) on the pedalboard
A set of pipes belonging to a single manual controlled by some type of on/off switch
At least three per manual, up to 30 or more per manual on a large instrument
More commonly used manuals have more stops, pedalboard has less
Names: e.g. Diapason, Bourdon, give indication of type and tone quality
The on/off switch is a drawstop or stoptab
The name is written on the drawstop or stoptab, with the size in feet which gives the pitch
A single set of pipes belonging to a stop
In most cases, one per stop,

but in “Mixture” stops 2, 3 or 4 or more ranks per stop with different pitches
Individual sound-producing tubes of various sizes, shapes and materials
Usually 61 per rank on keyboard stops, 30 on pedalboard stops, occasionally less
Sometimes more to allow for couplings
A single pipe is part of a single rank and stop

Stop types
The sound is produced by air on a edge.
The sound is produced by a vibrating reed.
The end of the pipe is open.
The end of the pipe is closed.
Typical organ sound, usually produced by a wide, open pipe.
A thin, nasal tone, usually produced by a thin open pipe.
A flute sound, usually produced by a stopped pipe.