Tracker action
From Wikipedia, the free encyclopedia
Tracker action is a term used in reference to pipe organs to indicate a mechanical linkage between the key 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 via an electrical link or an electrically assisted pneumatic system respectively.
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[edit] History
[edit] Ancient History
Organs trace their history as far back as at least the 3rd Century B.C. with an organ-like 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.
[edit] Baroque and Classical
This expiation continued well into the 17th and 18th centuries, with the height of tracker action usage peaking in the early part of the 18th century (around Bach’s day).
Since the use of the organ was very scarce during the Classical Period, no great developments took place in its mechanical nature.
[edit] Romantic
Upon the advent of the Romantic Period and renewed use of organ in repertoire, the organ was forced to become larger, louder, and more expressive than ever. The use of tracker action became obsolete as the size and physicals behind the operation became too physically cumbersome. At which point in time, Pneumatic Action became the prime form of action in organs.
[edit] Today
Even today, many organs are still built using the principles of the tracker action. Some active builders of tracker action organs include: 'Taylor and Boody' (builder's website) of Staunton, Virginia, 'Flentrop Orgelbouw B.V.' (builder's website) of Zaandam, Holland, and C.B. Fisk (builder's website)of Gloucester, MA.
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[edit] 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 condensely 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.
[edit] Tracker action and other kinds of action
Tracker action is one type of action. More generally, the four kinds of action used in pipe organs are as follows:
- Tracker action as described in this article;
- 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;
- Hydraulic action in which a non-compressible fluid such as water is used to actuate the organ pipes indirectly (in combination with another kind of action) or directly. Hydraulic action is generally only found on hydraulophones or on pipe organs that include a hydraulphone as part of a larger instrument. An example of this kind of hybrid pipe organ is the main centerpiece out in front of the Ontario Science Centre, in which a hydralophone organ console has hydraulic action to control the opening and closing of air valves, as well as water flow, on organ pipes. Advantages of hydraulic action are quick response (compared to pneumatic action) due to the non-compressible nature of the fluid. Hydraulic action also allows the organist to achieve subtle changes in volume, pitch, timbre, etc., of each organ pipe, by way of slight changes in the way in which the hydraulic fluid is pressed or manipulated. Typically, though not necessarily, hydraulic action is used with water jets rather than hard keys. By using water jets as the keys, hydraulic action provides the musically intricate expression of the tracker organ, but takes it a step further, allowing the organist to manipuate each fluid jet with multiple degrees of freedom, in a wider variety of ways than merely pressing down on the one degree of freedom afforded by each key on a tracker organ.
[edit] 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.
[edit] Advantages claimed for tracker action
- Organs using tracker action are usually seen as more reliable.
- Tracker action supposedly gives the organist more control over the exact moment air enters the pipe (i.e. more sensitive, more exact)
- Tracker action instruments are considered "more authentic" for music of the Baroque and Classical periods, since this music was originally played on such instruments
[edit] Perceived 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 sound.
