Tracker action is a term used in reference to pipe organs and steam calliopes 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 "direct electric action" and "electro-pneumatic action", which connect the key to the valve through an electrical link or an electrically assisted pneumatic system respectively, or "tubular-pneumatic action" which utilizes a change of pressure within lead tubing which connects the key to the valve pneumatic.
Organs trace their history as far back as at least the 3rd century BC with an organlike device known as the hydraulis. Also known as a "water organ" or "Roman organ", the hydraulis was an instrument in which water was used as a source of power to push wind through organ pipes. (It is 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 rudimentary 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.
Contemporary
Although tracker action was less utilized in the early 20th century, particularly in England and America, its use has enjoyed a strong renaissance in the same areas since World War II, especially in instruments modeled 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 of Staunton, Virginia, Paul Fritts of Tacoma, Washington, Flentrop Orgelbouw B.V. of Zaandam, the Netherlands, and C. B. Fisk, Inc. of Gloucester, Massachusetts.
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Components of the action
A roller board with rollers and trackers from a 1970 D. A. Flentrop organInterior of the organ at Cradley Heath Baptist Church showing the tracker action. The rollers transmit movement sideways to line up with the pipes.
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. They are thin strips of wood, roughly 10mm wide and 2mm thick. Although flexible, at rest they hold their shape. Playing a note pulls on the end nearer to the keyboard, so they are in tension while the note is playing. The term comes from the Latin verb "trahere", to draw (in the sense of "pull"); cf. modern English tractor.
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 250mm.
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 angle. Squares can also come in a "T" shape and form.
Rollers— Wooden shafts that rotate. Used for parallel direction in vertical or horizontal motion. They have small levers on each end, like cranks.
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 that 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. Steam calliopes, such as those built by Thomas J. Nichol in the early twentieth century, used a very simplified tracker mechanism. For actions used in all forms of pipe organs, see pipe organ construction.
Regulation
Tracker action at Cradley Heath Baptist Church showing adjusters on tracker ends which engage with the keys of the great organ.
Because of construction tolerances, a means of adjustment, or regulation, of the action has to be provided. This is commonly done by having a threaded wire end on the wooden tracker rods. A circular nut varies the effective length of the tracker where it engages with other parts of the action. One objective of correct regulation is that the keys on each manual have the same rest height and distance of travel when pressed. The regulation wrongly set at one extreme can cause a note to sound when no keys are pressed. This may also be caused by the action sticking after the key is released. The other extreme is that notes do not sound, or sound feebly, when a key is pressed.
Kinds of action
Besides tracker 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 of tracker action
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
Tracker action gives the organist more precise control over the exact moment air enters the pipe.
This control affects the attack and release of a note through different touch. Before the invention of electric action, the organ was a touch-sensitive instrument.
Tracker action requires less maintenance than other types of action since there are no pneumatics to be re-leathered, no electric contacts to tarnish and no wires to break.
Disadvantages
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 can almost always be overcome through correct use of body weight. The invention of the Barker lever was also meant to counteract this problem, by providing a pneumatic assist while retaining a completely-mechanical action.
Remote placement of sections of the organ are dependent on the distance the mechanical linkages can successfully extend, as opposed to the unlimited extendability of electric wires in electropneumatic organs.
The tracker mechanism is often noisy. In quieter passages, the clicking and clattering of the mechanism can be quite distracting.
A keyboard instrument is a musical instrument played using a keyboard, a row of levers which are pressed by the fingers. The most common of these are the piano, organ, and various electronic keyboards, including synthesizers and digital pianos. Other keyboard instruments include celestas, which are struck idiophones operated by a keyboard, and carillons, which are usually housed in bell towers or belfries of churches or municipal buildings.
The pipe organ is a musical instrument that produces sound by driving pressurized air through the organ pipes selected from a keyboard. Because each pipe produces a single pitch, the pipes are provided in sets called ranks, each of which has a common timbre and volume throughout the keyboard compass. Most organs have many ranks of pipes of differing timbre, pitch, and volume that the player can employ singly or in combination through the use of controls called stops.
In music, the organ is a keyboard instrument of one or more pipe divisions or other means for producing tones, each played from its own manual, with the hands, or pedalboard, with the feet.
A key is a specific part of a musical instrument. The purpose and function of the part in question depend on the instrument.
An organ stop is a component of a pipe organ that admits pressurized air to a set of organ pipes. Its name comes from the fact that stops can be used selectively by the organist; each can be "on", or "off".
Book music is a medium for storing the music played on mechanical organs, mainly of European manufacture. Book music is made from thick cardboard, containing perforated holes specifying the musical notes to be played, with the book folded zig-zag style. Unlike the heavy pinned barrels, which could only contain a few tunes of fixed length, that had been used on earlier instruments, book music enabled large repertoires to be built up. The length of each tune was no longer determined by the physical dimensions of the instrument.
A barrel organ is a French mechanical musical instrument consisting of bellows and one or more ranks of pipes housed in a case, usually of wood, and often highly decorated. The basic principle is the same as a traditional pipe organ, but rather than being played by an organist, the barrel organ is activated either by a person turning a crank, or by clockwork driven by weights or springs. The pieces of music are encoded onto wooden barrels, which are analogous to the keyboard of the traditional pipe organ. A person which plays a barrel organ is known as an organ grinder.
A pedalboard is a keyboard played with the feet that is usually used to produce the low-pitched bass line of a piece of music. A pedalboard has long, narrow lever-style keys laid out in the same semitone scalar pattern as a manual keyboard, with longer keys for C, D, E, F, G, A and B, and shorter, raised keys for C♯, D♯, F♯, G♯ and A♯. Training in pedal technique is part of standard organ pedagogy in church music and art music.
A theatre organ is a type of pipe organ developed to accompany silent films, from the 1900s to the 1920s.
The water organ or hydraulic organ is a type of pipe organ blown by air, where the power source pushing the air is derived by water from a natural source or by a manual pump. Consequently, the water organ lacks a bellows, blower, or compressor.
A manual is a musical keyboard designed to be played with the hands, on an instrument such as a pipe organ, harpsichord, clavichord, electronic organ, melodica, or synthesizer. The term "manual" is used with regard to any hand keyboard on these instruments to distinguish it from the pedalboard, which is a keyboard that the organist plays with their feet. It is proper to use "manual" rather than "keyboard", then, when referring to the hand keyboards on any instrument that has a pedalboard.
Keyboard expression is the ability of a keyboard musical instrument to change tone or other qualities of the sound in response to velocity, pressure or other variations in how the performer depresses the keys of the musical keyboard. Expression types include:
An expression pedal is an important control found on many musical instruments including organs, electronic keyboards, and pedal steel guitar. The musician uses the pedal to control different aspects of the sound, commonly volume. Separate expression pedals can often be added to a guitar amplifier or effects unit and used to control many different aspects of the tone.
The electro-pneumatic action is a control system by the mean of air pressure for pipe organs, whereby air pressure, controlled by an electric current and operated by the keys of an organ console, opens and closes valves within wind chests, allowing the pipes to speak. This system also allows the console to be physically detached from the organ itself. The only connection was via an electrical cable from the console to the relay, with some early organ consoles utilizing a separate wind supply to operate combination pistons.
A crescendo pedal is a large pedal commonly found on medium-sized and larger pipe organs, either partially or fully recessed within the organ console. The crescendo pedal incrementally activates stops as it is pressed forward and removes stops as it is depressed backward. The addition of stops, in order from quietest to loudest, creates the effect of a crescendo. The crescendo pedal is located directly above the pedalboard, to the right of any expression pedals that may be present. In actual use, the operation of the crescendo pedal usually does not move the draw knobs or stop tabs on the console; the stops are electronically activated inside the organ. Often an indicator light or lights will be present on the console to inform the organist of when the crescendo pedal is activated and how far it is engaged.
The pipe organ is played from an area called the console or keydesk, which holds the manuals (keyboards), pedals, and stop controls. In electric-action organs, the console is often movable. This allows for greater flexibility in placement of the console for various activities. Some very large organs, such as the van den Heuvel organ at the Church of St. Eustache in Paris, have more than one console, enabling the organ to be played from several locations depending on the nature of the performance.
Registration is the technique of choosing and combining the stops of a pipe organ in order to produce a particular sound. Registration can also refer to a particular combination of stops, which may be recalled through combination action. The registration chosen for a particular piece will be determined by a number of factors, including the composer's indications, the time and place in which the piece was composed, the organ the piece is played upon, and the acoustic environment within which the organ resides.
"Tubular-pneumatic action" refers to an apparatus used in many pipe organs built during the late 19th and early 20th centuries. The term "tubular" refers to the extensive use of lead tubing to connect the organ's console to the valves that control the delivery of "wind" to the organ's pipes. Many such organs are extant 100 or more years after their construction.
Direct electric action is one of various systems used in pipe organs to control the flow of air (wind) into the organ's pipes when the corresponding keys or pedals are depressed. In direct electric action, the valves beneath the pipes are opened directly by electro-magnet solenoids, while with electro-pneumatic action, the electro-magnet's action admits air into a pneumatic or small bellows which in turn operates the pipe's valve.
Music technology is the study or the use of any device, mechanism, machine or tool by a musician or composer to make or perform music; to compose, notate, playback or record songs or pieces; or to analyze or edit music.
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