Editing Pipe organ (section)

===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>