The choir division of the organ at St. Raphael's Cathedral in Dubuque, Iowa. Shown here are several ranks of pipes, each of which would be controlled from one of the stops on the organ.

An organ stop can mean one of three things: Image File history File linksMetadata StRaphaelsDubOrganSmall. ... Image File history File linksMetadata StRaphaelsDubOrganSmall. ...

• The control on an organ console that selects a particular sound.
• The mechanism, and in particular the organ pipes, used to produce a particular sound.
• The sound itself.

Organ in Katharinenkirche, Frankfurt am Main, Germany Modern style pipe organ at the concert hall of Aletheia University in Matou, Taiwan The organ is a keyboard instrument with one or more manuals, and usually a pedalboard. ... An organ pipe is one of the tuned resonators that produces the main sound of a pipe organ. ...

Principles of organ stops

Stops have particular names according to the kind of pipes used to create the sound and the style of organ.

Single-rank stops, the majority, are usually marked with an Hindu-Arabic numerals indicating the pitch; it originated as the length, in feet, of the rank's longest pipe. Registration usually begins with an 8' on the manual and a 16' on the pedal; the pedal thus normally sounds an octave lower than played, providing the "full-bodied" sound typical of the organ. Halving the number raises the pitch by an octave; in growing a registration it is usual to draw next the 4', 2', etc. on the manual and the 8', 4', etc. on the pedal. Numbers other than powers of 2 appear; these are called mutations. The 5 1/3', 2 2/3', 1 1/3' series sounds a G for a C; the rarer 3 1/5', 1 3/5', 4/5' sounds an E for a C. Hindu-Arabic numerals also known as Arabic Numerals, Hindu numerals, European numerals, and Western numerals are the most common set of symbols used to represent numbers around the world. ...

The most common multi-rank stops are mixtures, and are usually marked with a roman numeral indicating the number of ranks. Though it seems somehow wasteful to not provide the ranks separately, a mixture rank may break - drop an octave - as one goes up the scale to avoid shrillness, making it inappropriate for use apart. The name applied to the mixture usually codes for the particular chord provided, but octaves and fifths are most common; e.g. a Quint III might provide the 5th, 8ve, and 12th; an Acuta IV might have the 15th, 17th, 19th, and 23rd. Mixtures are usually used to boost harmonics, but some are appropriate as solo stops. A mixture is a multi-rank organ stop most commonly of principal, or diapason, tone quality. ... The system of Roman numerals is a numeral system originating in ancient Rome, and was adapted from Etruscan numerals. ... In acoustics and telecommunication, the harmonic of a wave is a component frequency of the signal that is an integer multiple of the fundamental frequency. ...

The next most common multi-rank stops are voix célestes, two identical ranks except one is slightly out of tune. But celestes are often presented as pairs of stops, since they don't break like mixtures. Literally, heavenly voice in French, this is an Organ stop that is intentionally tuned slightly off-pitch. ...

Sometimes a single rank has multiple stops. In one form, a divided or half stop, only the higher or lower pipes are drawn on. In another form, borrowing or unification, each stop may draw the rank to a different keyboard or to one keyboard at different pitches.

Flue stops, such as principals, flutes, and strings, are essentially end-blown whistles. Reed stops, such as trumpets or vox humanas consist of a metal reed vibrating in a full- or partial-length resonator. Short-length reed resonators of unusual shape are often called "vowel chambers." A principal is: The head of an educational institution. ... The examples and perspective in this article or section may not represent a worldwide view. ... Trumpeter redirects to here. ... The vox humana (Latin for human voice) is a stop on the pipe organ so-named because of its supposed resemblance to the human voice. ...

Names of stops are somewhat organ builder specific - a stop with a same name can have slightly different timbres on different organs.

Many organs have accoustic stops, where a sense of pitch is created one octave below the actual length of the pipes. These are almost invariably referred to as Accoustic Bass 32' ... meaning that the stops are, in fact, 16' pipes but producing the effect of a 32' stop. True 32' stops are much more effective (obviously) than the faux ones. Some organs (currently only two) have true full length 64' stops, one being in Sydney, Australia (see link below).

Mechanics of the organ stops

In pipe organs, each key on a keyboard is connected to each pipe in the ranks or rows of pipes connected to that particular keyboard. When the key is pressed, air is allowed to flow up from the blower.

The organ console at St. Raphael's Cathedral, Dubuque, Iowa. The stop knobs on this console are placed to the left and right of the keyboards.

In order to control what pipes will sound, stops were developed for organs. A stop is made up of material that fits underneath the pipes for each row, or rows in mixture stop. When the stop is closed, the air is kept from flowing up into the pipes in that rank. When the stop knob is pulled out, the material slides out from under the pipe. When a key for the rank's division is pushed, the air from the windchest is allowed to flow up, and into the pipe to create the noise. If more than one rank is open, the air will flow into the pipes in each open rank. This gives the organist a great deal of flexibility in what sound the organ will produce. This is the console for the organ at the Cathedral of St. ... This is the console for the organ at the Cathedral of St. ... Saint Raphaels Cathedral Saint Raphaels is the cathedral parish for the Archdiocese of Dubuque, in Iowa. ... Downtown Dubuque and the Riverfront Dubuque is a city in Dubuque County, Iowa, United States. ... This article or section does not cite its references or sources. ...

Organ consoles are connected to the stops by varying means. Those organs that have a console where the stop knobs are directly connected to the stops are referred to as having mechanical action. Those that are not directly connected often rely on electronics to control the opening and closing of a stop. Many organs have a system of combination action, allowing the organist to quickly open or close several stops at once. A combination action is a system designed to capture specific organ registrations to be recalled instantaneously by the player while he is playing. ...

Stop tabs on an electronic organ, located above the uppermost keyboard. Compare this placement to that of the stop knobs on the pipe organ console pictured above.

In electronic organs that do not have pipes, the stops may be operated by tabs instead of knobs, which are typically located above the manuals. In theater organs and their electronic equivalents, the stop tabs are traditionally arranged in a half-moon formation surrounding the manuals. Regardless of the physical configuration of the stop controls, opening a stop on an electronic organ merely adds the "rank" in question through various means. The means used have changed over the years since the introduction of the electric organ in the first part of the 20th century. Image File history File linksMetadata Download high-resolution version (1552x1164, 322 KB) Summary stop tabs on an electronic organ Licensing I, the creator of this work, hereby release it into the public domain. ... Image File history File linksMetadata Download high-resolution version (1552x1164, 322 KB) Summary stop tabs on an electronic organ Licensing I, the creator of this work, hereby release it into the public domain. ... A theatre organ is an organ installed in a movie theatre, most often modelled after the style originally devised by Robert Hope-Jones, which he called a unit orchestra. Such instruments were typically built to provide the greatest possible variety of timbres with the fewest possible pipes, and often had...

Common stop names

• principal - usually available in several sizes
• mixture - the most generic sort of compound stop
• gamba - a rank of narrow-scaled pipes, giving a string-like sound (see viola da gamba)
• bourdon - usually a stopped flute of a low pitch
• diapason - generally synonymous with principal
• voix céleste - a stop that is intentionally tuned slightly off-pitch in order to produce a gentle vibrato or tremolo effect.
• vox humana - a type of reed stop
• trumpet - a loud reed stop, usually with full-length resonators flared to form a bell
• trombone
• flute - a rank of broad-scaled pipes, open, covered, chimneyed, or conical, giving a sound similar to a flute or a recorder
• flautino
• oboe - a reed stop that produces a sound similar to the orchestral instrument
• cello - similar to gamba
• bombarde - an exceptionally loud reed stop, or a division containing several exceptionally loud reed stops

See also list of pipe organ stops. A principal is: The head of an educational institution. ... A mixture is a multi-rank organ stop most commonly of principal, or diapason, tone quality. ... Various Viola da gamba The viol or viola da gamba family of musical instruments is related to the vihuela, rebec, etc. ... The name Bourdun is derived from the French word for buzz and normally denotes a stopped flute/flue type of pipe in an organ, though in organ building the stop has no buzz, but rather a very dark, heavy tone, strong in fundamental, with little overtone development. ... The examples and perspective in this article or section may not represent a worldwide view. ... The word diapason (pronounced ) is another name for the musical interval of the octave, especially in the context of Pythagorean intervals. ... A principal is: The head of an educational institution. ... Literally, heavenly voice in French, this is an Organ stop that is intentionally tuned slightly off-pitch. ... The vox humana (Latin for human voice) is a stop on the pipe organ so-named because of its supposed resemblance to the human voice. ... Trumpeter redirects to here. ... The trombone is a musical instrument in the brass family. ... The examples and perspective in this article or section may not represent a worldwide view. ... The examples and perspective in this article or section may not represent a worldwide view. ... Various recorders The recorder is a woodwind musical instrument of the family known as fipple flutes or internal duct flutes—whistle-like instruments which include the tin whistle and ocarina. ... Modern Oboe The oboe is a double reed musical instrument of the woodwind family. ... A cello The violoncello, almost always abbreviated to cello (the c is pronounced as the ch in cheese), is a stringed instrument and a member of the violin family. ... Gamba is a port in western Gabon with a population of around 8,000 people. ... Bombardes from Kevrenn an Arvorig The bombarde is a French folk instrument from Brittany. ... An organ stop can mean one of three things: The control on an organ console that selects a particular sound. ...

The link http://www.sydneyorgan.com/STH64.mp3 is to a sound byte demonstrating the sound made by a 64' stop (recorded at the Sydney Town Hall, on the Grand Organ in the Centennial Hall). The stop is question is called the Contra Trombone. There are only two, true 64' stops in the world.

Further reading

• Stevens Irwin Dictionary of Pipe Organ Stops
• George Ashdown Audsley Organ Stops and Their Artistic Registration

External links

• Encyclopedia of Organ Stops