A Tibia Clausa is a type of

pipe organ The pipe organ is a musical instrument that produces sound by driving pressurized air (called ''wind'') through the organ pipes selected from a keyboard. Because each pipe produces a single pitch, the pipes are provided in sets called ''ranks ...

pipe. It is a large-scale, stopped wood flute pipe, usually with a leathered lip. The rank was invented by

Robert Hope-Jones Robert Hope-Jones (9 February 1859 – 13 September 1914) was an English musician who is considered to be the inventor of the theatre organ in the early 20th century. He thought that a pipe organ should be able to imitate the instruments of ...

. Tibia Clausas provides the basic foundation tone of the organ with few

overtone An overtone is any resonant frequency above the fundamental frequency of a sound. (An overtone may or may not be a harmonic) In other words, overtones are all pitches higher than the lowest pitch within an individual sound; the fundamental i ...

s or harmonics. The Tibia Clausa is arguably the most important rank of pipes in a theatre pipe organ, with some organs having as many as 5. The stop shares similarities with the '' Bourdon'' and the ''

Gedackt Gedackt (also spelled gedeckt) is the name of a family of stops in pipe organ building. They are one of the most common types of organ flue pipe. The name stems from the Middle High German word ''gedact'', meaning "capped" or "covered". History ...

'' found in some church

s. In the 18th and 19th centuries, Tibia Clausa was sometimes used as an alternate name for Doppelflöte. Most tibias are made from wood, as by

Wurlitzer The Rudolph Wurlitzer Company, usually referred to as simply Wurlitzer, is an American company started in Cincinnati in 1853 by German immigrant (Franz) Rudolph Wurlitzer. The company initially imported stringed, woodwind and brass instruments ...

etc., although examples of metal tibias may be found made by the John Compton Organ Company. The Tibia Clausa, or Tibia, is generally found at 16′, 8′, 4′ and 2′ pitches as a unified rank. The mutation ranks Tibia Quint 5′, Twelfth 2′ and Tierce 1′ are also drawn from this unified rank of 97 pipes. In some larger organs, a second Tibia rank may be present, extended to 1′ instead of 16′, allowing a 1′ Nineteenth mutation and a 1′ Piccolo to be drawn from this rank. A few of the largest theatre organs, and some church organs, may have a separate 32′ Tibia Clausa rank of 12 pipes. In smaller organs, a '' Bourdon'' or ''Stopped Diapason'' may be substituted for a Tibia Clausa at 16′ pitch. The Tibia may be voiced on wind pressures from 10″ to 25″. The Tibia is often used as a chorus stop (several footages played simultaneously, such as 16' 8' 4' and 2', usually with tremulant; although it is also used as a solo stop in quieter or more reflective musical passages. Other variants of the Tibia include: Tibia Bass, Tibia Flute, Tibia Major, Tibia Minor, Tibia Plena (open tibia) and Tibia Rex.

References

External links

Encyclopedia of Organ Stops: Tibia Clausa

Flute type organ stops {{FreeReed-instrument-stub

References

Further reading

External links