The knobs on each side of the keyboards control which row of pipes, called ranks, are to be played. Each rank of pipes (usually 61 pipes) has a specific sound and pitch. The type of sound is indicated by the name, and the pitch is indicated by the number on each drawknob. The number 8 indicates that the rank of pipes will sound at the standard pitch, like a piano. The number 4 indicates the pitch will actually be an octave higher.

When a button, called a piston and located below each keyboard, is pressed a combination of drawknobs can be either pulled out or pushed in. This is called "combination action". These pistons are programmed by the organist, enabling him or her to quickly change registrations.

The organist has 256 different levels of memory available to program the combination action. The console also has an instant transposer.

This organ was constructed over a period of two years. Here the builder, Lawrence Nevin, is installing pipes in the swell division. Notice the empty holes in the foreground? These are the holes in the windchest, mentioned in the console photo caption. A pipe will soon fill each one of the holes when it is "voiced" to blend with its neighboring pipes.

This division, located behind the left side of the facade, is enclosed in a chamber with louvered shutters which enable the folume of the organ to be controlled by the organist. Swell divisions are known for their reed pipes, shown here.

Because of the complicated acoustical properties of this historic sanctuary the gallery division was added to help lead congregational singing. It is really a small organ in and of itself, and is controlled by the bottom keyboard on the console. Here our organist shows one of the pipes on during an "organ tour".