Tracker action

Tracker action is a term used in reference to pipe organs to indicate a mechanical linkage between keys or pedals pressed by the organist and the valve that allows air to flow into pipe(s) of the corresponding note. This is in contrast to electrical or electro-pneumatic actions, which connect the key to the valve through an electrical link or an electrically assisted pneumatic system respectively.

History

Ancient History

Organs trace their history as far back as at least the 3rd Century B.C. with an organlike device known as the Hydraulis (also known as a water organ, and Roman organ, in which water was used as a source of power to push wind through organ pipes, not to be confused with the hydraulic action of a hydraulophone, an instrument that actually uses water to produce the sound, not just as a source of power). While the control of air pressure was controlled by water pressure (hence the name), the action was a rudimental form of modern action.

It was not until the mid 14th century that the action needed to be explored and expanded as finally more pipes were added, as well as the addition of stops, and ultimately multiple cases and keyboards.

Baroque and Classical

This continued in the 17th and 18th centuries.No particularly great developments took place in the Classical Period.

Romantic

In the Romantic Period came a new style of organ building. The organ became larger and louder and pneumatically assisted action became the norm in large instruments, to offset the extreme key weight caused by high wind pressures.

Today

Although tracker action was less utilized in the early twentieth century, particularly in England and America, its use has enjoyed a strong renaissance in the same areas since World War II, especially in instruments modelled on historical antecedents. Today, many builders are using tracker action throughout the world, and it has been successfully employed in organs of many styles. Some active builders of tracker action organs include: 'Taylor and Boody' ( [http://www.taylorandboody.com builder's website] ) of Staunton, Virginia, 'Paul Fritts' ( [http://www.frittsorgan.com builder's website] ) of Tacoma, Washington, 'Flentrop Orgelbouw B.V.' ( [http://www.flentrop.nl builder's website] ) of Zaandam, Holland, and 'C. B. Fisk, Inc.' ( [http://www.cbfisk.com builder's website] )of Gloucester, MA.

Currently, the world's largest mechanical (tracker) action organic was built by Ronald Sharp in the Concert Hall of the Sydney Opera House, Sydney, Australia, and includes over 10,500 pipes.

Components of the Action

The action consists of many types of devices used for the playing of such said organ, as listed below:

* Trackers – trackers are the portions of the action used to make a pulling motion. Trackers can be used over long distances.
* Stickers – used for a pushing motion; often paired with trackers. Their length is limited by the material, though most of the time, capping off at about 10 inches.
* Levers – levers are used to transfer from a tracker (pulling) to a sticker (pushing), or a general change of direction, or both.
* Backfalls – backfalls are used for motion over a small or short distance where trackers and stickers would be otherwise illogical to use. As a natural result, the motion also changes direction.
* Squares – a specific type of lever commonly used in organs which is at a right (90°) angle. Squares can also come in a “T” shape and form.
* Roller – used for parallel direction in vertical or horizontal motion by use of rotating or rolling the round instrument with small levers on each end enabling such said motion.
* Roller board – location upon which rollers are attached (note: rollers are often used densely in one section of the action and so are often closely associated with the roller board.)
* Stops – knobs which indirectly control the flow of air over certain ranks of pipes. They are activated with a pulling motion by hand, and deactivated (or stopped) by pushing them shut.
* Trundle – Trundles are used as a substitute for levers in the action associated with the Stops and Slider boards.

The above is a list of mechanisms unique to tracker action. For actions used in all forms of pipe organs see pipe organ construction.

Tracker action and other kinds of action

Tracker action is the most artistically successful type of action. Two other kinds of action used in pipe organs are as follows:
*Electric action in which electric valves are used to allow wind into the pipes;
*Pneumatic action in which compressed air is used to control valves that allow wind into the pipes;

Advantages and disadvantages

Currently, some organ builders use tracker action in new organs, others use electric action, and still others use either type depending on the instrument. There are builders and organists who have strong feelings regarding the advantages of one type of action over another.

Advantages of tracker action

* Tracker action gives the organist more control over the exact moment air enters the pipe (i.e. more exact)
* This control extends to actually being able to affect the attack and release of a note through different touch - before the invention of electric action, the organ was a touch sensitive instrument.

Disadvantages of tracker action

* The "console" or "keydesk" (where the organist actually plays) cannot be moved.
* On some instruments, as more stops are used, the organist must apply more pressure/force to a key in order for it to play, resulting in heavy playing action when playing full organ. This can be particularly burdensome when two or more manuals are coupled. Problems of heavy action, however, can almost always be overcome through correct use of body weight.