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. The organ of Bristol Cathedral, Bristol, England. ...

History

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 orgàn). While the control of air pressure was controlled by water pressure (hence the name), the action was a rudimental form of modern action. The organ of Bristol Cathedral, Bristol, England. ... Hydraulis is an early type of pipe organ that operated by converting the dynamic energy of water (hydor) into air pressure to drive the pipes. ...

It was not until the mid 14th century that the action needed to be explored and expanded as finally more pipes where added, as well as the addition of stops, and ultimately multiple cases and keyboards. The word stop, when used alone, has several possible meanings in the English language. ...

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). Johann Sebastian Bach (21 March 1685 O.S. – 28 July 1750 N.S.) was a prolific German composer and organist whose sacred and secular works for choir, orchestra and solo instruments drew together almost all of the strands of the baroque style and brought it to its ultimate maturity. ...

Since the use of the organ was very scarce during the Classical Period, no great developments took place in its mechanical nature. The Classical period in Western music occurred from about 1730 through 1820, despite considerable overlap at both ends with preceding and following periods, as is true for all musical eras. ...

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 then ever. The use of tracker action become obsolete as the size and physicals behind the operation became to physically cumbersome. At which point in time, Pneumatic Action became the prime form of action in organs. Romantic music is defined as the period of European classical music that runs roughly from the early 1800s to the first decade of the 20th century, as well as music written according to the norms and styles of that period. ...

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.

Components of the Action

A roller board with rollers and trackers from a 1970 D. A. Flentrop organ

The action consists of many types of devices used for the playing of such said organ, as listed below: Image File history File linksMetadata DSCN03502. ...

• 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 – Poles which indirectly control the flow of air over certain ranks of pipes. They are activated with a pulling motion by hand, or deactivated (or stopped) though by pushing them shut.
• Trundle – Trundles are used a substitute for levers in the action associated with the Stops and Slider boards.

The above list is of mechanisms unique to tracker action. For action used in all forms of pipe organs see pipe organ construction. The organ of Bristol Cathedral, Bristol, England. ...

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 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

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.