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Beginners' Guide To The Organ


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#1 Teigr

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Posted 11 October 2007 - 01:15

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.
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#2 Maizie

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Posted 11 October 2007 - 07:58

woot.gif clap.gif clap.gif clap.gif clap.gif hurrah.gif

I knew nothing about the organ until I started reading this forum. I tried to find out a bit more about it, by reading things like the Wikipedia article on organs. But this is fantastically clear and very useful to someone who needs it explained in 'ideas of one syllable' (a box with a row of holes each of which has an upside down no-finger-holed recorder on it biggrin.gif woot.gif that's a description I can understand)

I look forward to "diapasons" because it's an interesting word but whenever I've tried to read something to tell me what it means I just don't seem to understand (or if I do, it falls out of my head three seconds later!)
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#3 Guest: BachPensioner_*

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Posted 11 October 2007 - 08:02

Very interesting - really enjoyed reading this
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#4 fsharpminor

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Posted 11 October 2007 - 08:24

Teigr, as an organist familiar with what you have written, thats a darn good effort at trying to explain an organ in simple terms. Well done !
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#5 Teigr

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Posted 11 October 2007 - 09:52

Thanks! :-)

Quick clarification to last night's offering...

Sliders.
Broadly speaking, you have a long, flat strip of wood with 61 holes in it, to match up with the 61 holes in the top of the windchest for a particular rank of pipes. Imagine that one end of it is connected to a little knob which sticks through a hole in the console, so an organist can reach it.
To start with, the holes in the slider are positioned so that they are in between the holes in the windchest. Press keys and nothing happens.
Pull the knob towards you and the slider moves along with it, bringing all the holes into alignment. Now, when you press a key, air can get into the relevent pipe, as the slider is set so that they are all available.
This is called "drawing a stop".

The actual mechanics are a little more complicated, to allow for the layout of the organ, but that's the general principle behind it.

Each rank of pipes has its own slider, which controls the availability of that rank.
Ranks are often referred to as stops.


I think one of the barriers to understanding the organ is that even if you can see the console (and that's a big if, as it could be in a loft, or tucked away behind a screen or behind the choir stalls), and can see what the organist is doing, there's no obvious connection between what he does and the sounds you hear.
You see someone playing what looks a bit like a mutant piano, with a whole bunch of knobs and buttons on it. He plays the piano-looking bits, but keeps jumping around from one to another, and he keeps messing around with all the widgets and the sound you hear, which is definitely nothing like a piano, changes. But the link between what he does and what you hear isn't easy to mae sense of.
With most other instruments, if you watch someone playing, you can see the whole instrument. With the organ, if you can see the console, you're really watching someone playing by remote control.



Action

Going to keep this /very/ simple for the time being.
There are two main types of action that are commonly found these days. Tracker (or mechanical) action is used to refer to an organ where there is a mechanical linkage between the keys and the pallets.
A tracker instrument has to have the console very close to the pipework and it gives a very immediate response.
Electro-pneumatic instruments are the organ version of "fly-by-wire". Then you press a key, you close an electrical connection, a signal zips along a cable, and that triggers the opening of a pallet. This means that the pipework can be in one part of the building and the console in a completely different part.

Generally speaking, an electro-pneumatic will have a smoother keyboard action than a tracker, because the keys aren't connected to a whole bunch of mechanical stuff. But, with a detached console (that's what you call it when the console is positioned away from the rest of the organ), you have a time delay between pressing the key and hearing the note. It's not a very long delay, but it takes a bit of getting used to.

I played an organ yesterday that had (mostly) electro-pneumatic action, but with the console set where you'd expect on a tracker. Best of both worlds - smooth /and/ responsive.

One bonus of a tracker is that you can vary the attack - the speed at which you depress the key affects the speed at which the pallet opens. It's not like changing the volume of a note on the piano by how fast you hit the key, but it does allow a little control over the start and end of a sound. You don't have any subtlety of attack with an e-p.


One important difference between playing the organ and playing a piano is the fact that an organ pipe will sound for as long as you keep the key depressed. The moment you release the key, the sound stops (there is no 'sustain' pedal), but while you hold the key down, the sound remains absolutely constant (there is no decay).
(There's a actually a very very quick crescendo at the start of a note and a very very quick diminuendo at the end, as the pallet opens and closes, but you can ignore that for most purposes - it's important for an organist to be aware of when they're trying to develop a really smooth legato touch. Those extrenely brief moments at the beginning and end of a note are what a tracker gives you more control over.)

T.
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#6 Guest: mrbouffant_*

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Posted 11 October 2007 - 10:35

Nice posts Teigr! biggrin.gif

It's worth noting that expression pedals are not always positioned where you describe. I have played some instruments where it is offset to the far right (mostly triggers: see below). Not very comfortable!

There are different kinds of expression pedals:

Balanced (you tilt the pedal up or down and it stays where it is)

Infinite gradation (you push the pedal up and it acts like the volume button on a TV remote, more more more more more, or push it down for less less less less) - only ever played one instrument with this (Liverpool Cathedral)

Trigger (the pedal isn't balanced and will always flop into an open or close position unless you hold it with a pivoted piece of ratcheted wood which you knock out of the way with your ankle and let it settle into position again) - this are good fun: NOT

As with most things, these different types are best experienced in the flesh so I would recommend anyone going to a church service or whatever to c0ck a snook at the organ and see what that instrument has. Be brave and talk to the organist about it too! They don't bite (mostly!)
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#7 Teigr

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Posted 11 October 2007 - 10:54

Thanks Mr B! :-)

I've only come across ones where they're somewhere near the middle so far. This is why I'm relying on you and the other experienced organists to chip in on this thread.

I was already aware of the different types of expression pedals, but have only ever played with balanced ones. I can imagine plenty of scope for accidents happenning with the trigger type if you find yourself playing one and are used to balanced. (I know I'd forget, probably several times, resulting in sudden and unwelcome changes of volume and startling bangs of the shutters.)

Banging the shutters is the organ equivalent of slamming a door - it's considered bad form. So even when you want a very fast change, you try to finish it very carefully.
Mr B (or someone) - has anyone written anything that actually calls for the organist to bang the shutters for effect in a piece?

Even with balanced pedals, they vary a lot. How far they move, how easily they move, how much you need to move them to get the desired effect, how best to position your foot so your instep is over the fulcrum - all takes a bit of getting used to.

My most disconcerting experience with the swell pedal so far was the first time I played the Guilmant Duo Pastorale on the 3-manual tracker I have some of my lessons on. I'd worked on it with my other teacher (on an e-p) and had been practicing it on that instrument and another e-p. Played it to John just as a dry-run at playing it to someone else before the exam. Moved the swell pedal as normal and nothing happenned. It really threw me. Apparently there would be a noticable change in volume to anyone sitting in the nave, but at the console there was hardly any difference between having the box open and having it closed.

This is another thing that organists have to contend with. The sound can be very different in different parts of the building, and the console isn't always well placed to use the sound there as a guide to the sound elsewhere. So, if you play a particular organ, it can be useful to get someone else to play it sometime while you walk around the building.

T.
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#8 Guest: skylark_*

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Posted 11 October 2007 - 10:56

This is fascinating, thank you so much Teigr smile.gif

I don't go to church so I don't get to listen to the organ very much, but when I heard Simon Lindley and mwl1 play it at Leeds Parish Church in the summer, I thought it was wonderful. I didn't know until then that you could get so much variety on the organ.

I'd like to ask a question which has always puzzled me but which I know is going to sound really really stupid, but I'll ask it anyway....

When I go to the Bridgewater Hall to listen to something like Saint-Saens' Organ Symphony, the organist plays from a console at the front of the stage. Is it connected in some way to the pipes at the back or is he playing a completely separate instrument? ph34r.gif
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#9 Teigr

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Posted 11 October 2007 - 11:02

You're welcome.

I don't know that particular instrument, but it's probably an electo-pneumatic with a detached console. (See post #5 for details).

T.
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#10 Guest: mrbouffant_*

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Posted 11 October 2007 - 11:06

I think Bridgewater is tracker which means it is mechanically connected from the console to the pipes, unless this is a separate, moveable console which is probably solid-state (i.e. computer signals go down a thin wire to the computers at the back which then activate the organ mechanism)
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#11 Teigr

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Posted 11 October 2007 - 11:12

*looks it up*

OK, the main console is mechanical, but there's a mobile console which is electric, connected by fibre-optic cable.

Anyone feeling up to explaining how you connect a remote console to a tracker?
(I don't!)

T.

p.s. Please don't just say "with a fibre-optic cable" - I want to know how it works. ;-)
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#12 Guest: skylark_*

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Posted 11 October 2007 - 11:22

Ah, I see, thank you for clearing up that mystery smile.gif

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#13 Teigr

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Posted 11 October 2007 - 11:24

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

T.
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#14 That Minx

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Posted 11 October 2007 - 11:46

[
When I go to the Bridgewater Hall to listen to something like Saint-Saens' Organ Symphony, the organist plays from a console at the front of the stage. Is it connected in some way to the pipes at the back or is he playing a completely separate instrument? :ph34r:
[/quote]

Skylark reminds me of an Olivier Latry recital I attended some years ago at the Bridgwater Hall. I overheard a woman expressing amazement at '... getting such a HUGE sound out of such a TINY instrument!'
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#15 mel2

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Posted 11 October 2007 - 11:53

Fascinating posts, Teigr; many thanks! smile.gif

Been playing the things 10 years and didn't know any of this in any detail (textbooks on the subject make my eyes glaze over and I've yet to have a single lesson).

I shall keep an eye on this thread for further enlightenment.

Mel
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