The new organ will have 2 blowers producing air (‘wind’) which is held in large reservoirs. How does the wind get from the reservoir into the right pipes when the keys are pressed?

The pipes sit in ranks on a board full of holes (the ‘soundboard’) on top of an airtight wooden box (the ‘windchest’) which is full of wind from the reservoir under the right pressure.  If there are 61 keys on a manual, each stop on that manual will usually have 61 pipes, although some stops (called “Compounds” or “Mixtures”) can have more than one pipe per note.

Each rank of pipes is arranged on the top of the chest, which contains wind from the reservoir. The pipes for each individual note sit together on their own ‘key channel’, a pathway carved out of the windchest that admits wind to all the pipes for that note. The wind is admitted into the key channel via the ‘pallet’, a small strip of wood and leather that is connected to the keys either via electric circuits. The pallet is held in place under the pipes by a spring. When a key is pressed, the corresponding pallet opens, admitting wind into the key channel. Between the pipes and the key channel are the ‘sliders’. A slider is a thin strip of wood, with one hole for each pipe drilled through it. The slider can be moved via the stop action. When the organist activates the stop, the slider moves so that the holes are directly under the pipes, so allowing wind to the pipes in that stop when the pallets are opened by the keys.

So, in order for a pipe to sound in a slider chest, two events must occur:

1. A stop must be drawn to move its slider into a position to admit wind to that rank by having its holes line up with the bottoms of the pipes; and
2. A key must be pressed, opening its pallet, so that wind is admitted to the key channel and then goes up through the holes into those pipes whose sliders are in position.

The slider chest aids in blending and intonation between pipes of the same note, as all the pipes controlled by a single key are fed from the same key channel. Slider chests are used for everything from very small organs of 2 or 3 stops to large organs of over 100 stops.