Editing Pipe organ (section)

==Construction==
A pipe organ contains one or more sets of pipes, a wind system, and one or more keyboards. The pipes produce sound when pressurized air produced by the wind system passes through them. An action connects the keyboards to the pipes. [[Organ stop|Stops]] allow the organist to control which ranks of pipes sound at a given time. The organist operates the stops and the keyboards from the [[Organ console|console]].

===Pipes===
{{Main|Organ pipe}}
[[File:Salt Lake City Organ.jpg|thumb|The [[Salt Lake Tabernacle organ]] found at the [[Salt Lake Tabernacle]] in [[Salt Lake City]], Utah, has 11,623 pipes and accompanies [[The Tabernacle Choir at Temple Square]] and [[Orchestra at Temple Square]].]]
Organ pipes are made from either wood or metal and produce sound ("speak") when air under pressure ("wind") is directed through them.<ref>Randel "Organ", 578.</ref> As one pipe produces a single [[pitch (music)|pitch]], multiple pipes are necessary to accommodate the [[musical scale]]. The greater the length of the pipe, the lower its resulting pitch will be.<ref name="randel579">Randel "Organ", 579.</ref> The [[timbre]] and volume of the sound produced by a pipe depends on the volume of air delivered to the pipe and the manner in which it is constructed and voiced, the latter adjusted by the [[Organ building|builder]] to produce the desired tone and volume. Hence a pipe's volume cannot be readily changed while playing.<ref name="randel579" />

[[File:Spain Andalusia Seville BW 2015-10-23 12-30-25 stitch.jpg|thumb|right|Interior of the [[Seville Cathedral]], showing the pipes of the organ.]]
Organ pipes are divided into [[flue pipe]]s and [[reed pipe]]s according to their design and timbre. Flue pipes produce sound by forcing air through a [[fipple]], like that of a [[recorder (musical instrument)|recorder]], whereas reed pipes produce sound via a beating [[Reed (instrument)|reed]], like that of a clarinet or saxophone.<ref>Bicknell "Organ construction", 27.</ref>

Pipes are arranged by timbre and pitch into ranks. A rank is a set of pipes of the same timbre but multiple pitches (one for each note on the keyboard), which is mounted (usually vertically) onto a [[#Wind system|windchest]].<ref name="Bicknell 20">Bicknell "Organ construction", 20.</ref> The [[organ stop#Mechanics|stop mechanism]] admits air to each rank. For a given pipe to sound, the stop governing the pipe's rank must be engaged, and the key corresponding to its pitch must be depressed. Ranks of pipes are organized into groups called divisions. Each division generally is played from its own keyboard and conceptually comprises an individual instrument within the organ.<ref>Gleason, 3–4.</ref>

=== Action ===
An organ contains two actions, or systems of moving parts: the keys, and the stops. The key action causes wind to be admitted into an organ pipe while a key is depressed. The stop action causes a rank of pipes to be engaged (i.e. playable by the keys) while a stop is in its "on" position. An action may be mechanical, pneumatic, or electrical (or some combination of these, such as electro-pneumatic).<ref>William H. Barnes "The Contemporary American Organ"</ref> The key action is independent of the stop action, allowing an organ to combine a mechanical key action with an electric stop action.

A key action in which the keys are connected to the windchests by only rods and levers is a mechanical or [[tracker action]]. When the organist depresses a key, the corresponding rod (called a tracker) pulls open its pallet, allowing wind to enter the pipe.<ref>Bicknell "Organ construction", 22–23.</ref>
[[File:Pipe organ in Honduras.jpg|alt=Immaculate Conception Cathedral, Comayagua|thumb|Pipes from the organ of the [[Immaculate Conception Cathedral, Comayagua|Comayagua Cathedral]] in Honduras.]]
In a mechanical stop action, each stop control operates a valve for a whole rank of pipes. When the organist selects a stop, the valve allows wind to reach the selected rank.<ref name="Bicknell 20"/> The first kind of control used for this purpose was a draw [[organ stop|stop knob]], which the organist selects by pulling (or drawing) toward himself/herself. Pulling all of the knobs thus activates all available pipes, and is the origin of the idiom "[[wikt:pull out all the stops|to pull out all the stops]]".<ref>{{Cite web |date=December 7, 2018 |title=What Does It Mean to 'Pull Out All the Stops'? |url=https://www.merriam-webster.com/wordplay/pull-out-all-the-stops-phrase-history-pipe-organ |website=Merriam-Webster |quote=To pull out all the stops literally, then, is to pull out every knob so that air is allowed to blast through every rank as the organist plays, which creates a powerful blast of unfiltered sound.}}</ref> More modern stop selectors, utilized in electric actions, are ordinary electrical switches and/or magnetic valves operated by a rocker tab.<ref>{{Cite web |date=2024 |title=Organ Types and Components |url=https://organ.byu.edu/organ-types-and-components/ |access-date=June 26, 2024 |website=[[Brigham Young University|BYU]] Organ}}</ref>

Tracker action has been used from antiquity to modern times. Before the pallet opens, wind pressure augments tension of the pallet spring, but once the pallet opens, only the spring tension is felt at the key. This sudden decrease of key pressure against the finger provides a "breakaway" feel.<ref>{{Cite web |url=http://www.pykett.org.uk/the_physics_of_organ_actions.htm#Fore-touch%20Weight |title=The Physics of Organ Actions, Part 1: Mechanical Actions, "Fore-touch weight" |access-date=4 May 2019 |archive-date=16 December 2019 |archive-url=https://web.archive.org/web/20191216191326/http://www.pykett.org.uk/the_physics_of_organ_actions.htm#Fore-touch%20Weight |url-status=dead }}</ref>

A later development was the [[tubular-pneumatic action]], which uses changes of pressure within lead tubing to operate pneumatic valves throughout the instrument. This allowed a lighter touch, and more flexibility in the location of the console, within a roughly 50-foot (15-m) limit. This type of construction was used in the late 19th century and early 20th century, and has had only rare application since the 1920s.<ref name="ReferenceA">William H. Barnes, "The Contemporary American Organ"</ref>

A more recent development is the electric action, which uses low voltage DC to control the key and/or stop mechanisms. Electricity may control the action indirectly by activating air pressure valves (pneumatics), in which case the action is [[electro-pneumatic action|electro-pneumatic]]. In such actions, an electromagnet attracts a small pilot valve which lets wind go to a bellows (the "pneumatic" component) which opens the pallet. When electricity operates the action directly without the assistance of pneumatics, it is commonly referred to as [[direct electric action]].<ref name="ReferenceA"/> In this type, the electromagnet's armature carries a disc pallet.

When electrical wiring alone is used to connect the console to the windchest, electric actions allow the console to be separated at any practical distance from the rest of the organ, and to be movable.<ref>Bicknell "Organ construction", 23–24.</ref> Electric stop actions can be controlled at the console by stop knobs, by pivoted tilting tablets, or rocker tabs. These are simple switches, like wall switches for room lights. Some may include electromagnets for automatic setting or resetting when combinations are selected.

Computers have made it possible to connect the console and windchests using narrow data cables instead of the much larger bundles of simple electric cables. Embedded computers in the console and near the windchests communicate with each other via various complex multiplexing syntaxes, comparable to MIDI.

<gallery widths="200px" heights="170px">
File:SommierOrgue.jpg|Cross-section of one note of a mechanical-action windchest. Trackers attach to the wires hanging through the bottom board at the left. A wire pulls down on the pallet (valve) against the tension of the V-shaped spring. Wind under pressure surrounds the pallet, and when it is pulled down, the wide rectangular chamber above the pallet feeds wind to all pipes of this note and stop; note the cutaway passages at the top.
File:Cradley Heath Baptist Church Organ A01.JPG|Interior of the organ at [[Cradley Heath Baptist Church]] showing the tracker action.  The black rods, called rollers, rotate to transmit movement sideways to line up with the pipes.
File:Schleiflade Tontraktur Animation.gif|Schematic animation of a mechanical-action windchest with three ranks of pipes
File:Guercino - St. Cecilia - Google Art Project.jpg|[[Saint Cecilia]], patron saint of music, depicted playing the pipe organ
</gallery>

===Wind system===
[[File:Detall orgue 7.JPG|thumb|Bellows of a pipe organ at [[Museu de la Música de Barcelona]]]]
<!--Remove image for now, at a smaller size, it does not really show the wind system, only a wind pipe, so actually not very useful.[[File:StRaphaelOrganRearView.JPG|thumb|right|A view from behind the organ in St. Raphael's Cathedral in [[Dubuque, Iowa]], showing part of the wind system]]-->

The wind system consists of the parts that produce, store, and deliver wind to the pipes. Pipe organ wind pressures are on the order of {{convert|0.10|psi|kPa|abbr=on}}. Organ builders traditionally measure organ wind using a water U-tube [[Liquid Column|manometer]], which gives the pressure as the difference in water levels in the two legs of the manometer. The difference in water level is proportional to the difference in pressure between the wind and the atmosphere.<ref>{{cite book|title=Process Instruments and Controls Handbook|editor=Douglas M. Considine|publisher=McGraw-Hill|year=1974|edition=Second|pages=3–4|isbn=0-07-012428-0}}</ref> The 0.10 psi above would register as 2.75 [[Inch of water|inches of water]] (70&nbsp;[[Centimetre of water|mmAq]]). An Italian organ from the [[Renaissance music|Renaissance period]] may be on only {{convert|2.2|in|mm}},<ref>Dalton, 168.</ref> while (in the extreme) solo stops in some large 20th-century organs may require up to {{convert|50|in|mm}}. In isolated, extreme cases, some stops have been voiced on {{convert|100|in|mm}}.{{efn|The [[Boardwalk Hall Auditorium Organ]] in [[Atlantic City]] has four stops on 100&nbsp;inches and ten stops on 50. [http://www.oddmusic.com/gallery/om02700.html Atlantic City Convention Hall Organ]. Oddmusic.com. Retrieved on 4 July 2007.}}

With the exception of [[water organ]]s, playing the organ before the invention of [[motors]] required at least one person to operate the [[bellows]]. When signaled by the organist, a ''calcant'' would operate a set of bellows, supplying the organ with wind.<ref>Bicknell "Organ construction", 18.</ref> Rather than hire a calcant, an organist might practise on some other instrument such as a [[clavichord]] or [[harpsichord]].<ref>Koopman, Ton (1991). "[https://www.jstor.org/stable/965836 Dietrich Buxtehude's organ works: A practical help] {{Webarchive|url=https://web.archive.org/web/20190203143624/https://www.jstor.org/stable/965836 |date=3 February 2019 }}". ''The Musical Times'' '''123''' (1777) (subscription required, though relevant reference is viewable in preview). Retrieved on 22 May 2007.</ref> By the mid-19th-century bellows were also operated by [[water engine]]s,<ref>{{cite web |url=http://www.douglas-self.com/MUSEUM/POWER/waterengine/waterengine6.htm |title=Water Engines: Page 6 |publisher=Douglas-self.com |date=10 June 2011 |access-date=22 October 2011 |archive-date=20 January 2012 |archive-url=https://web.archive.org/web/20120120155848/http://www.douglas-self.com/MUSEUM/POWER/waterengine/waterengine6.htm |url-status=live }}</ref> steam engines or gasoline engines.<ref>{{cite web|url=http://www.bowralanglican.org.au/history_pipe_organ.html |archive-url=https://archive.today/20091013162343/http://www.bowralanglican.org.au/history_pipe_organ.html |url-status=dead |archive-date=13 October 2009 |title=St Jude's: History Pipe Organ |publisher=Bowralanglican.org.au |access-date=22 October 2011 }}</ref><ref>{{cite web |url=http://www.akc-orgel.be/akcv2/main.php?lang=en&tekstid=16 |title=Antwerpse Kathedraalconcerten vzw |publisher=Akc-orgel.be |access-date=22 October 2011 |archive-date=30 September 2011 |archive-url=https://web.archive.org/web/20110930074615/http://www.akc-orgel.be/akcv2/main.php?lang=en&tekstid=16 |url-status=live }}</ref><ref>{{cite web |url=http://www.nzorgan.com/vandr/blowers3.htm |title=organ blowers 3 |publisher=Nzorgan.com |date=26 July 1997 |access-date=22 October 2011 |url-status=dead |archive-url=https://web.archive.org/web/20110927165438/http://www.nzorgan.com/vandr/blowers3.htm |archive-date=27 September 2011 }}</ref> Starting in the 1860s bellows were gradually replaced by rotating turbines which were later directly connected to electrical motors.<ref>Sefl, 70–71</ref> This made it possible for organists to practice regularly on the organ. Most organs, both new and historic, have electric [[Centrifugal fan|blowers]], although some can still be operated manually.<ref>[http://www.cbfisk.com/do/DisplayInstrumentAbout/instId/72 About Opus 72] {{webarchive|url=https://web.archive.org/web/20081205183718/http://www.cbfisk.com/do/DisplayInstrumentAbout/instId/72 |date=5 December 2008 }}. [[C. B. Fisk|C. B. Fisk, Inc.]] Retrieved on 13 May 2008.</ref> The wind supplied is stored in one or more regulators to maintain a constant pressure in the ''windchests'' until the action allows it to flow into the pipes.<ref>Bicknell "Organ construction", 18–20.</ref>

===Stops===
{{Main|Organ stop}}

Each stop usually controls one rank of pipes, although [[Mixture (music)|mixtures]] and undulating stops (such as the [[Voix céleste]]) control multiple ranks.<ref name="Bicknell 26-27">Bicknell "Organ construction", 26–27.</ref> The name of the stop reflects not only the stop's timbre and construction, but also the style of the organ in which it resides. For example, the names on an organ built in the north German Baroque style generally will be derived from the German language, while the names of similar stops on an organ in the French Romantic style will usually be French. Most countries tend to use only their own languages for stop nomenclature. English-speaking nations as well as Japan are more receptive to foreign nomenclature.{{Citation needed|date=February 2019}} Stop names are not standardized: two otherwise identical stops from different organs may have different names.<ref>Bicknell "Organ construction", 27–28.</ref>

To facilitate a large range of timbres, organ stops exist at different pitch levels. A stop that sounds at [[unison|unison pitch]] when a key is depressed is called an 8′ (pronounced "eight-foot") pitch. This refers to the speaking length of the lowest-sounding pipe in that rank, which is approximately {{convert|8|ft|spell=in}}. For the same reason, a stop that sounds an octave higher is at 4′ pitch, and one that sounds two octaves higher is at 2′ pitch. Likewise, a stop that sounds an octave lower than unison pitch is at 16′ pitch, and one that sounds two octaves lower is at 32′ pitch.<ref name="Bicknell 26-27"/> Stops of different pitch levels are designed to be played simultaneously.

The label on a stop knob or rocker tab indicates the stop's name and its pitch in feet. Stops that control multiple ranks display a Roman numeral indicating the number of ranks present, instead of pitch.<ref>Johnson, David N. (1973). [https://books.google.com/books?id=e447xDPoQqoC&pg=PA9 Instruction Book for Beginning Organists]. Revised edition. Augsburg Fortress. p. 9. {{ISBN|978-0-8066-0423-7}}. Google Book search. Retrieved on 15 August 2008.</ref> Thus, a stop labelled "Open Diapason 8′ " is a single-rank [[Open diapason|diapason]] stop sounding at 8′ pitch. A stop labelled "Mixture&nbsp;V" is a five-rank mixture.

Sometimes, a single rank of pipes may be able to be controlled by several stops, allowing the rank to be played at multiple pitches or on multiple manuals. Such a rank is said to be ''unified'' or ''borrowed''. For example, an 8′ Diapason rank may also be made available as a 4′ Octave. When both of these stops are selected and a key (for example, c′){{efn|name=Helmholtz|This article uses the [[Helmholtz pitch notation]] to indicate specific pitches.}} is pressed, two pipes of the same rank will sound: the pipe normally corresponding to the key played (c′), and the pipe one octave above that (c′′). Because the 8′ rank does not have enough pipes to sound the top octave of the keyboard at 4′ pitch, it is common for an extra octave of pipes used only for the borrowed 4′ stop to be added. In this case, the full rank of pipes (now an ''extended rank'') is one octave longer than the keyboard.{{efn|The purpose of extended ranks and of their being borrowed is to save on the number of pipes. For example, without unification, three stops may use 183 pipes. With unification three stops may borrow one extended rank of 85 pipes. That's 98 fewer pipes used for those three stops.}}

Special unpitched stops also appear in some organs. Among these are the [[Zimbelstern]] (a wheel of rotating bells), the nightingale (a pipe submerged in a small pool of water, creating the sound of a bird warbling when wind is admitted),<ref>Randel "Rossignol", 718.</ref> and the ''effet d'orage'' ("thunder effect", a device that sounds the lowest bass pipes simultaneously). Standard orchestral percussion instruments such as the drum, [[Tubular bell|chimes]], [[celesta]], and [[harp]] have also been imitated in organ building.<ref>Ahrens, 339; Kassel, 526–527</ref>

<gallery widths="200px" heights="200px">
File:Weingarten Basilika Gabler-Orgel Register rechts.jpg|Stop knobs of the Baroque organ in [[Organ of the Basilica of St. Martin (Weingarten)|Weingarten]], Germany
File:M.P. Möller Chapel Pipe Organ 1936.jpg|M.P. Möller three-rank chapel organ (1936)
</gallery>

===Console===
{{Main|Organ console}}
[[File:Usnaconsole2.jpg|thumb|The five-manual, 522-stop detached console at the [[Naval Academy Chapel|United States Naval Academy Chapel]] crafted by R. A. Colby, Inc.{{efn|Organ built by [[M. P. Moller]], 1940.<ref>[http://www.usna.edu/Music/Accessable/organ.html USNA Music Department] {{Webarchive|url=https://web.archive.org/web/20081106213802/http://www.usna.edu/Music/Accessable/organ.html |date=6 November 2008 }}. [[United States Naval Academy]]. Retrieved on 4 March 2008.</ref>}}]]

The controls available to the organist, including the [[#Keyboards|keyboards]], [[#Couplers|couplers]], [[#Enclosure and expression pedals|expression pedals]], stops, and [[#Combination action|registration aids]] are accessed from the console.<ref>[http://www.agohq.org/guide/pages/pages_9_10/console.html Pipe Organ Guide] {{webarchive|url=https://web.archive.org/web/20080801202709/http://www.agohq.org/guide/pages/pages_9_10/console.html |date=1 August 2008 }}. [http://www.agohq.org/ American Guild of Organists] {{Webarchive|url=https://web.archive.org/web/20000706193712/http://www.agohq.org/guide/pages/pages_9_10/console.html |date=6 July 2000 }}. Retrieved on 13 August 2008.</ref> The console is either built into the [[#Casing|organ case]] or detached from it.

====Keyboards====
Keyboards played by the hands are known as ''[[manual (music)|manuals]]'' (from the [[Latin language|Latin]] ''{{lang|la|[https://en.wiktionary.org/wiki/manus mănus]}}'', meaning "hand"). The keyboard played by the feet is a ''[[Pedal keyboard|pedalboard]]'' (from the [[Latin language|Latin]] ''{{lang|la|[https://en.wiktionary.org/wiki/pes#Latin pēs], pĕdis}}'', meaning "foot"). Every organ has at least one manual (most have two or more), and most have a pedalboard. Each keyboard is named for a particular division of the organ (a group of ranks) and generally controls only the stops from that division. The [[range (music)|range]] of the keyboards has varied widely across time and between countries. Most current specifications call for two or more manuals with sixty-one notes (five octaves, from C to c″″) and a pedalboard with thirty or thirty-two notes (two and a half octaves, from C to f′ or g′).{{efn||name=Helmholtz}}<ref>[http://www.agohq.org/guide/pages/pages_5_5/frameset01.html Pipe Organ Guide] {{webarchive|url=https://web.archive.org/web/20070927154656/http://www.agohq.org/guide/pages/pages_5_5/frameset01.html |date=27 September 2007 }}. [[American Guild of Organists]]. Retrieved on 25 June 2007.</ref>

====Couplers====
A ''coupler'' allows the stops of one division to be played from the keyboard of another division. For example, a coupler labelled "Swell to Great" allows the stops drawn in the Swell division to be played on the Great manual. This coupler is a unison coupler, because it causes the pipes of the Swell division to sound at the same pitch as the keys played on the Great manual. Coupling allows stops from different divisions to be combined to create various tonal effects. It also allows every stop of the organ to be played simultaneously from one manual.<ref name="crumhorn">{{cite web|title=A brief tour of a pipe organ |publisher=Crumhorn Labs |url=http://www.crumhorn-labs.com/Documentation/CurrentUserGuide/HTML/HauptwerkInstallUserGuideFiles/TourOfAPipeOrgan.html |access-date=19 April 2008 |url-status=dead |archive-url=https://web.archive.org/web/20080410182430/http://www.crumhorn-labs.com/Documentation/CurrentUserGuide/HTML/HauptwerkInstallUserGuideFiles/TourOfAPipeOrgan.html |archive-date=10 April 2008 }}</ref>

''Octave couplers'', which add the pipes an octave above (super-octave) or below (sub-octave) each note that is played, may operate on one division only (for example, the Swell super octave, which adds the octave above what is played on the Swell to itself), or act as a coupler to another keyboard (for example, the Swell super-octave to Great, which adds to the Great manual the ranks of the Swell division an octave above what is played).<ref name="crumhorn"/>

In addition, larger organs may use ''[[unison]] off'' couplers, which prevent the stops pulled in a particular division from sounding at their normal pitch. These can be used in combination with octave couplers to create innovative aural effects, and can also be used to rearrange the order of the manuals to make specific pieces easier to play.<ref name="crumhorn"/>

====Enclosure and expression pedals====
{{Main|Expression pedal}}
[[File:Salemer Münster Orgel Spieltisch und Pedal.jpg|thumb|The console of the organ in [[Salem Abbey|Salem Minster]] in [[Salem, Bodensee|Salem]], Germany.{{efn|Organ built by Wilhelm Schwarz, 1901}} The expression pedal is visible directly above the pedalboard.]]

''Enclosure'' refers to a system that allows for the [[Dynamics (music)|control of volume]] without requiring the addition or subtraction of stops. In a two-manual organ with Great and Swell divisions, the Swell will be enclosed. In larger organs, parts or all of the Choir and Solo divisions may also be enclosed.<ref name="swell">Wicks "Swell division", "Swell shades".</ref> The pipes of an enclosed division are placed in a chamber generally called the ''swell box''. At least one side of the box is constructed from horizontal or vertical palettes known as ''swell shades'', which operate in a similar way to [[Window blind|Venetian blinds]]; their position can be adjusted from the console. When the swell shades are open, more sound is heard than when they are closed.<ref name="swell"/>  Sometimes the shades are exposed, but they are often concealed behind a row of facade-pipes or a grill.

The most common method of controlling the louvers is the [[Expression pedal#Balanced swell pedal|balanced swell pedal]]. This device is usually placed above the centre of the pedalboard and is configured to rotate away from the organist from a near-vertical position (in which the shades are closed) to a near-horizontal position (in which the shades are open).<ref>Wicks "Expression pedals".</ref> An organ may also have a similar-looking [[crescendo pedal]], found alongside any expression pedals. Pressing the crescendo pedal forward cumulatively activates the stops of the organ, starting with the softest and ending with the loudest; pressing it backward reverses this process.<ref>Wicks "Crescendo pedal".</ref>

====Combination action====
{{Main|Combination action}}
Organ stops can be combined in many permutations, resulting in a great variety of sounds. A combination action can be used to switch instantly from one combination of stops (called a ''registration'') to another. Combination actions feature small buttons called ''pistons'' that can be pressed by the organist, generally located beneath the keys of each manual (thumb pistons) or above the pedalboard (toe pistons).<ref>[http://www.agohq.org/guide/pages/pages_16_17/frameset01.html Pipe Organ Guide] {{webarchive|url=https://web.archive.org/web/20100707005342/http://www.agohq.org/guide/pages/pages_16_17/frameset01.html |date=7 July 2010 }}. [http://www.agohq.org/ American Guild of Organists] {{Webarchive|url=https://web.archive.org/web/20000706193712/http://www.agohq.org/guide/pages/pages_9_10/console.html |date=6 July 2000 }}. Retrieved on 13 August 2008.</ref> The pistons may be ''divisional'' (affecting only a single division) or ''general'' (affecting all the divisions), and are either preset by the organ builder or can be altered by the organist. Modern combination actions operate via computer memory, and can store several channels of registrations.<ref>[http://www.toff.org.uk/CONSOLE/electronicsetter.html Electronic setter] {{webarchive|url=https://web.archive.org/web/20090511210128/http://www.toff.org.uk/CONSOLE/electronicsetter.html |date=11 May 2009 }}. The Cinema Organ Society. Retrieved on 7 July 2009.
</ref>

===Casing===
[[File:Erfurt St. Severi 01.jpg|thumb|left|upright|The organ of the Severikirche in [[Erfurt]], Thuringia, Germany has a highly decorative case with ornate carvings and cherubs.]]
The pipes, action, and wind system are almost always contained in a case, the design of which also may incorporate the console. The case blends the organ's sound and aids in projecting it into the room.<ref>Randel "Organ", 580.</ref> The case is often designed to complement the building's architectural style and it may contain ornamental carvings and other decorations. The visible portion of the case, called the ''façade'', will most often contain pipes, which may be either sounding pipes or dummy pipes solely for decoration. The façade pipes may be plain, [[burnishing (metal)|burnished]], [[gilding|gilded]], or painted<ref>Kassel, 146.</ref> and are usually referred to as ''(en) [[:fr:Montre (orgue)|montre]]'' within the context of the [[French organ school]].<ref>Peter Williams, [[Barbara Owen (organist)|Barbara Owen]], [[New Grove Dictionary of Music and Musicians]], ''ORGAN STOP'': Montre (Fr.). The case pipes of the French organ, corresponding to the English Open Diapason, the German Prestant, the Italian Principale, etc. Early alternative names were ‘le principal de devant’, ‘devanture en monstre’ (Reims Cathedral, 1570). The tone of the classical French Montre was somewhat more fluty than the various English Open Diapason types or German Principals.</ref><ref>G.A. AUDSLEY ''Art of Organ-Building'', Vol. I, p.544 {{ISBN|0-486-21314-5}}: ''MONTRE'', Fr. -The name commonly applied by the French organ builders to such foundations and organ-toned metal stops as may be mounted or displayed in the buffet or case of an organ; accordingly, the MONTRES, which are usually of burnished tin, may be of 32 ft., 16 ft., and 8 ft. speaking lengths, as in the Organ in the Royal Church at Saint Denis near Paris. Sometimes the name is applied to the PRESTANT 4 ft., when its pipes are mounted. All the MONTRES are most carefully fashioned and finished, producing, when of tin brightly burnished, a beautiful effect in combination with the dark wood-work of the case.</ref>

Organ cases occasionally feature a few ranks of pipes protruding horizontally from the case in the manner of a row of trumpets. These are referred to as pipes ''[[en chamade]]'' and are particularly common in organs of the [[Iberian peninsula]] and large 20th-century instruments.<ref>Bicknell "The organ case", 66–67.</ref>

Many organs, particularly those built in the early 20th century, are contained in one or more rooms called organ chambers. Because sound does not project from a chamber into the room as clearly as from a freestanding organ case, enchambered organs may sound muffled and distant.<ref>Wicks "Organ Chamber".</ref> For this reason, some modern builders, particularly those building instruments specializing in polyphony rather than Romantic compositions, avoid this unless the architecture of the room makes it necessary.

===Tuning and regulation===
{{main|Pipe organ tuning}}
[[File:Cradley Heath Baptist Church Organ A03.JPG|thumb|upright|right|Tracker action showing adjusters on tracker ends which engage with the keys of the great organ]]

The goal of tuning a pipe organ is to adjust the pitch of each pipe so that they all sound in tune with each other. How the pitch of each pipe is adjusted depends on the type and construction of that pipe.

Regulation adjusts the action so that all pipes sound correctly.  If the regulation is wrongly set, the keys may be at different heights, some pipes may sound when the keys are not pressed (a "cipher"), or pipes may not sound when a key is pressed.  Tracker action, for example in the organ of [[Cradley Heath Baptist Church]], includes adjustment nuts on the wire ends of the wooden trackers, which have the effect of changing the effective length of each tracker.