This oldest keyboard instrument of the history was not equipped with a keyboard at the beginning. The pipe organ originated from the invention of the pan pipes made from bamboos of different length into which air was blown to produce sound. The original organ, organus hydraulis or water organ, was first designed by the Greek physicist Ctesibius in the 3rd Century B.
Organ pipes are made from either wood or metal  and produce sound "speak" when air under pressure "wind" is directed through them. The greater the length of the pipe, the lower its resulting pitch will be. Organ pipes are divided into flue pipes and reed pipes according to their design and timbre.
Flue pipes produce sound by forcing air through a fipplelike that of a recorderwhereas reed pipes produce sound via a beating reedlike that of a clarinet or saxophone.
A rank is a set of pipes of the same timbre but multiple pitches one for each note on the keyboardwhich is mounted usually vertically onto a windchest. 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. 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.
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. When a key is depressed, the key action admits wind into a pipe.
The stop action allows the organist to control which ranks are engaged. An action may be mechanical, pneumatic, or electrical or some combination of these, such as electro-pneumatic action. A key action which physically connects the keys and the windchests is a mechanical or tracker action. Connection is achieved through a series of rods called trackers.
When the organist depresses a key, the corresponding tracker pulls open its pallet, allowing wind to enter the pipe. When the organist selects a stop, the valve allows wind to reach the selected rank.
This is the origin of the idiom " to pull out all the stops ". 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 provides a "breakaway" feel. A later development was the tubular-pneumatic actionwhich 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 foot m limit. This type of construction was used in the late 19th century to early 20th century, and has had only rare application since the s.
Electricity may control the action indirectly through air pressure valves pneumaticsin which case the action is electro-pneumatic. In such actions, an electromagnet attracts a small pilot valve which lets wind go to a bellows "pneumatic" which opens the pallet.
When electricity operates the action directly without the assistance of pneumatics, it is commonly referred to as direct electric action.
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.
These are simple switches, like wall switches for room lights. Some may include electromagnets for setting or resetting when combinations are selected. The most modern actions are primarily electronic, which connect the console and windchests via narrow data cables instead of the larger multiconductor cables of electric actions.
Boxes containing small embedded computers in the console and near the windchests translate console commands into fast serial data for the cable, and back into electrical commands at the windchest[s].
Pipe organ wind pressures are on the order of 0. Organ builders often measure organ wind using a U-tube manometer containing water, so commonly give its magnitude as the difference in water levels in the two legs of the manometer, rather than in units of pressure.
The difference in water level is proportional to the difference in pressure between the wind being measured and the atmosphere. An Italian organ from the Renaissance period may be on only 2. When signaled by the organist, a calcant would operate a set of bellows, supplying the organ with air.
Most organs, both new and historic, have electric blowers, although others can still be operated manually.A list of some of the most notable and largest pipe organs in the world can be viewed at List of pipe organs. The origins of the pipe organ can be traced back to the water organ in Ancient Greece, in the 3rd century BC, in which the wind supply was created with water pressure.
Their invention is what we now know as the pipe organ. At the start, pipe organs had only one timbre – a basic whistle sound, but over the next several hundred years, smart inventors and musicians made improvements in the technology.
Ctesibius, the inventor of the hydraulus, and the Venetian Georgius, who built the first organ north of the Alps, have already been mentioned, It is interesting to find a pope among the organ-builders of history: Sylvester II (), who seems to have built a hydraulic organ .
Electronic organ: Electronic organ, keyboard musical instrument in which tone is generated by electronic circuits and radiated by loudspeaker. This instrument, which emerged in the early 20th century, was designed as an economical and compact substitute for the much larger and more complex pipe organ.
The term organ encompasses reed organs and electronic organs but, unless otherwise specified, is usually understood to refer to pipe organs.
Although it is one of the most complex of all musical instruments, the organ has the longest and most involved history and the largest and oldest extant repertoire of any instrument in Western music. INVENTING THE ORGAN by John H.
Lienhard. Click here for audio of Episode Today, the invention of the pipe organ. The University of Houston's College of Engineering presents this series about the machines that make our civilization run, and the people whose ingenuity created them.