windchests

A windchest is a crucial component of a pipe organ, serving as the reservoir and distribution system for pressurized air that makes the organ pipes sound. It is essentially a large, airtight box that holds the air supplied by the organ's bellows or blower. When a key or stop button is pressed, a valve opens within the windchest, allowing air to flow into the corresponding pipe.

There are several types of windchests, with the most common being the slider chest and the pitman chest. In a slider chest, a movable strip called a "slider" is positioned beneath the pipes. When a stop is drawn, the slider moves to align holes in the chest with the bases of the pipes for that stop, allowing air to reach them. In a pitman chest, individual levers (pitmans) are connected to each pipe and operated by the key action, directly opening and closing valves. More complex designs like pneumatic and electric chests also exist, employing mechanisms to control airflow.

The construction of a windchest is critical for the organ's proper functioning. It must be airtight to maintain consistent air pressure and stable tuning. The placement and arrangement of pipes on the windchest also influence the organ's tonal design and layout. Modern windchests often incorporate sophisticated mechanisms to allow for greater flexibility in stop control and voicing.