Key Action
Before the introduction of electricity in pipe organs, air was supplied by large bellows driven by human hands and feet. As air was supplied to the pipe, it was let in by the pressure of an organist's finger on the key. As the key was depressed, a series of mechanical connections (including “trackers”) transferred this action to the pipe valve in the chest. As this valve opened, a constant supply of air was allowed into the pipe until the key was released.
All organs were of this mechanical-action (“tracker”) type until well into the nineteenth century. As the key action became heavier with larger and larger organs, air pressure and (later) electrical circuits were used for assistance.
Many modern instruments are built with tracker key action. The instrument at the right, for example, is a three-manual 21-rank instrument built in 1988 by Kenneth Jones for Brigham Young University. The console and case are integrated, which is characteristic of most tracker organs.
