Beginners' Guide To The Organ, Non-organists enquire within.... Options

[Teigr]

This thread is for people who don't know anything about organs to find out how they work, what the jargon means and what all the fuss is about.
I hope some of the more experienced organists will chip in with explanations and answers to questions (and corrections, as I'm bound to make some mistakes here!) and anyone is welcome to ask anything about organs (including "could you say that again, but without the jargon?").
The only stupid question is one you don't ask.


So, getting started....

The bit of the organ that you sit at and do things to when you play is usually called the console (sometimes called the keydesk when talking about certain types of organs). The keyboards are called manuals. A typical church organ will have 2 or 3 manuals, and a typical cathedral 4 or 5, but you can find instruments with anything from 1 to 7.
Most organs have a pedalboard. This is a bit like an oversized keyboard, played with the feet.
Most have one or more expression pedals. For the time being, think of them as a variable volume control. They are large tilting pedals set just above the main pedalboard, somewhere near the middle of it. (edit: Usually! On some instruments they are set to the far right.)

Somewhere near the manuals, you'll find the stop controls. Drawstops are knobs that you pull out and are the most usual sort to find on a church instrument. Tab stops are sort of flat switch things that you flip downwards. Either sort will be labelled, most with a number and a name.
The most usual place to find drawstops is on the jambs either side of the manuals. But some organs have them just above the uppermost manual.
Just below the keys, you'll probably find a series of little buttons on the front edge of each manual. These are called thumb pistons.


Imagine a large box, full of pressurized air. Imagine it has 61 holes in it, in a row. Each hole is covered and has a simple pipe (a bit like an upside-down recorder without any finger holes) directly above it, each one slightly smaller than the one before it (so it will give a higher pitched note if air flows through it). The widget (let's call it a pallet) that covers each hole is connected to the corresponding key of a 5-octave keyboard. When you press the key, the pallet moves out of the way and air can flow into the pipe, so that the note sounds.

That's the basic idea of how an organ works.
Each set of 61 matching pipes is called a rank.

Different types of pipes make different sorts of sounds.
So, you'd like to have several different sounds available for each note, which means several sets (ranks) of pipes.

Do you remember the game Stay Alive, with marbles resting on top of two sets of sliders (at 90 degrees to each other)? Each slider had holes in various places, but a marble would fall though only when both sliders were set so that they had a hole underneath the marble?
Organs are like that - to make a pipe sound you need to open two things. A slider (controlled by a drawstop) and the pallet (controlled by a key). If you've got both open, air can move through into the pipe and make a sound.
Until you draw a sounding (or speaking) stop for the manual, you can press the keys as much as you like and you won't get any sound.

Several ranks of pipes, grouped together and intended to be controlled by one manual, are called a division.
Most organs have one division for each manual and one more for the pedals.
This means that each manual has it's own collection of available sounds, and you can play with contrasting sounds by using one hand on one manual and the other on a different one. Or you can change back and forth between different manuals as you play.
You can also change the sounds by selecting different stops (and you can do this while you're playing, but it takes a bit of practice).

On a two-manual organ, the divisions are normally called Great and Swell.

All the pipes of the Swell division are inside a box, with louvred shutters on the front. If you close the shutters, you've basically shut the entire division away inside a closed box. This muffles the sound and makes it seem quieter to the listener. If you open the shutters gradually, you get a crescendo.
You control the position of the shutters using the swell pedal (which is an expression pedal). This is the volume control I mentioned earlier. You're not really changing the volume of sound the pipes produce, but you're changing how much of the sound you allow out of the box.
On a three-manual, the extra one is usually called the Choir and may, like the Swell, be an enclosed division (i.e. be in a box, with a pedal to control the shutters). In this case, the Swell and Choir divisions will be in two /separate/ boxes, and the console will have two expression pedals.

Some organs have more divisions than they have manuals. When this happens, two divisions share a manual and there will be one or more drawstops to control which is active.

If you have 4 divisions, the 4th might be Solo or Positive. If you have 5, you'll get both of those.
I'm sticking with the English names here for the time being. Foreign organs not only have different names, but the character of the divisions may be different, so it's not just a case of translating the names.

Unlike the piano, you can't affect the volume by how hard you strike the keys.
You've got two ways to change volume - open and close the swell box, or add and subtract stops (ranks). The more pipes you use at the same time, the more noise you'll make.
Some ranks are much louder than others, so for a quiet hymn you'll choose different stops than for a loud one, and then you'll add/subtract from there to create a little bit of variety between (or during) verses.

You can also engage things called Couplers which allow you to control the pipes belonging to one manual from a different one. These have names like "Swell to Great" and "Great to Pedal". They are controlled by drawstops, much like sounding stops (ranks) are.

The choice of stops, manuals and couplers that you're going to use for a given piece of music (and you might use several different set-ups within one piece) is called registration.
All the fussing around that you do while playing, aside from actually playing the notes, is known as organ management. (Changing stops, changing pistons, changing the expression pedal(s), changing manuals, etc.)

Explanation of stops (types (flues (flutes & diapasons) and reeds), names, lengths, mutations, etc.) to follow another time, along with explanation of the different types of action and the question of how the box full of air (windchest) works.

Ask if anything isn't clear. Chip in with corrections and clarifications if you've got any (note: I've deliberately simplified a few things).

T.

[Teigr]

You're welcome, but we seem to have uncovered a whole new mystery in the process... ;-)

T.