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

[Teigr]

Some random bits and pieces...
(I can't face starting the harmonic series this late at night - I'd be up for hours working on it.)

As well as explain how the beastie works, I'm trying to give the non-organists following this a few glimpses into our little world - hence the asides about things like post-it notes, mirrors and banging the shutters.

Organists can sometimes seem a bit cliquey - like we think we belong to a special club or something. In a way, we do. It's not that the organ is the hardest instrument to play and playing it makes us special. (Though it is almost certainly one of the harder instruments and playing it quite possibly makes us crazy!)
It's that it's a much less accessible instrument than most. It's not offered as an instrument to learn in (most) schools and although you can buy a digital practice instrument for home (and a few people have small pipe organs at home!), most people practice in church. So you get far fewer people learning the organ than learning the piano or the flute or the violin and suchlike.

Even if you have an instrument at home, you still need to practice on the one you play "for real" because, as you'll have realised by now, every instrument is different. They have different numbers of manuals, differently arranged pedalboards, different stops, with different types of controls for them, different accessories (pistons, etc.), different layouts, etc.
Most other instrumentalists don't have to practice for hours in a cold, dark church. (There's a thread about some of scary things - real or imagined - that people have come across while practicing.)

And then there's the whole issue of playing for services, which most organists do at some point, even if they don't hold a church appointment. Vicars who change the hymns just before the start of the service, conductors who casually say "I'd like this chant in E flat instead of F", Sunday School leaders who hand you a copy of the song the kiddies are going to lead (complete with actions - unfortunately not complete with harmony, just a melody line and, if you're lucky, guitar chord symbols). Yes, other people deal with similar issues, but probably not on such a regular basis. And while some people like to have lots of time to get a piece up to performance standard, an organist (and remember that many church organists are volunteer amateurs) has to deliver a public performance once or twice a week (maybe even more!), every week, with several hymns, some music before the service, a voluntary at the end and quite possibly some other bits and pieces during it, and maybe some accompaniments for choir stuff too.

So, organists can get a bit clannish sometimes - it's nice to be able to share horror stories with other people who understand what it's all about and who've been through similar things.
But most organists are very enthusiastic about the instrument in general and "their" instrument in particular.
So if you want to have a look at the one in your local church, do ask the organist. Chances are that he'll be pleased that someone is taking an interest and he'll probably be very happy to show you the console, maybe let you have a little go on it, tell you more about it and, if you're very lucky, he might be able to show you some of the innards (that's not always possible because it can be quite inaccessible and there may be health & safety issues).

It can also be a bit off-putting to people that we seem to be speaking a different language sometimes. The organ is a complicated instrument, so it has lots of jargon. There's the names for all the different bits, and the names for all the different stops (I've got several books about the organ, including one that's just about stops!) and a whole bunch of other terminology that we use. We don't do it on purpose and we don't do it to exclude other people - it's just that those terms are everyday parlance for organists and help us to communicate between ourselves. But hopefully this thread is helping you crack the code.



"I saw the lesser spotted marsh Harrison&Harrison!"
Some of us can also get a bit geeky or anoraky - like the sterotypical trainspotter, only we want to drive the thing as well as ticking off the number. ;-)
We're not /completely/ barmy - we're just enthusiastic about organs in their almost infinite variety.
And that's something other instrumentalists can probably relate to to some extent. There's a thread on the Strings forum at the moment in which people are enthusing about violins they've seen. And really, to most people, one violin looks (and sounds) very much like another. Even someone with no knowledge of organs or music would be able to spot that organs come in a bewildering range of shapes and sizes.

T.


edit:
I've just seen the post that Skylark made while I was making this one.

I would highly recommend that event to anyone who can get along to it. I went to something similar at a cathedral once (after I'd developed an interest in organs and decided I wanted to learn, but before I'd actually started learning). It was absolutely fascinating.
The organist brought along some spare pipes of different types to show people (and sounded them by blowing into the end - you have to be careful when you do that because of the lead content, so you shouldn't put the pipe in your mouth to blow it, instead you grip around the end of the pipe and blow into your fist). Then he played some snippets of music to show the scope of the instrument. Then took everyone who wanted to go up into the organ loft (not the console loft, but the area where the pipework lives!). I got to sound a pipe by sticking my hand inside the organ and physically moving a pallet (we were told we could do that, carefully). There was also a chance for people to have a quick look in the console loft, though I didn't (I was quite shy and wasn't already an organist). He'd also got the mobile single manual positive console attached and I did get to have a little play on that.
I would guess that an event aimed primarily at children and with a large audience wouldn't include a visit to the innards, but it should still be a wonderful experience.

[diapason]

LOVE IT LOVE IT LOVE IT

Man/woman/boy/girl? after my own heart Teigr. You are SO right - the organ is the most un-standard/unpredictable instrument of the lot. Layout, sound, response, comfort of playing, location dependancy - the environment in which the organ is placed will make it or break it. "The building is the best (or worst) stop on the instrument" said my oft quoted teacher who probably quoted someone else.

Organists ARE clannishy, cliquey, freaky, anoraky, geeky.............perm any 4 out of 5.......but some of us are straightforward normal everyday guys and gals who just enthuse over our instrument.

I am Secretary of a local organ society - mostly electronic organ as entertainment for "home enthusiasts". We have a professional or good amateur to play a two-hour concert for us each month. I, myself (hate that expression) am also "on the concert circuit"
Some of our society members think they know EVERYTHING that was ever written or said about the organ, yet talk the biggest load of gobbledygook to come from human mouths. Try and explain (patiently!) the difference between an electronic organ and the workings of a pipe organ.........they have NO idea. The art of regsitration may as well be written in some Star-Trek based lingo for all they know (or care).........and some of these people are my pupils.........H E A V E N H E L P M E...........you'd better believe it.

BUT............they love it!!!

Anyway, will get off your thread now.....and my soapbox.

Re:"Mixes and Muts"..........I have some unusual ones on my home digital classical instrument. It's a very well-endowed machine.

[Teigr]

Anyway, will get off your thread now.....and my soapbox.

It's not my thread - it's for everyone! I just got it started and have been doing most of the initial explanations. I'm probaby not a bad person to do them because I'm still new enough to it all that I can remember what it was like to be on the 'outside' - not understanding most of the jargon, asking lots of what I thought were silly questions, etc. but when we get to the more advanced stuff and to other types of organs, I'm going to need a LOT of input from those of you with more experience. And even with the basics, I need people to keep an eye on what I'm writing and pick up on any mistakes and clarify anything that I've said that might confuse people.

I'm finding it quite good to do. They say that you don't really understand something until you can explain it to someone else, so it's making me think quite hard. And it's going to help me find the gaps in my understanding and get them filled. :-)

I definitely agree that the organ is an instrument that's very difficult for non-organists to make any sense of. With most instruments, the player is interacting much more directly with the sound-producing aparatus, so an onlooker can understand at least the general idea of how it works.
If you watch a harpist, you can see that plucking strings makes notes. And longer strings make lower notes. You might have a few questions about how the player navigates around all those strings (some are colour-coded to give waypoints) or what the pedals or the little lever things are for (getting sharps and flats), but the basic principles are clear enough.
Same with a clarinet - you can see that someone blows into one end and changes the length of the tube (by covering more or fewer holes) to produce different notes. There'll be a few questions about the reed, the keywork and changing registers (how come you've covered a load more holes but the sound is higher?), but the general concept is fairly obvious.
But with the organ, you see the player doing things to a keyboard-type-thing on one side of a building and trumpety sounds emerge from the other side of the building, emanating from a contraption that looks a little like a collection of giant tin-whistles. Huh???

Organ music looks very scary too. People who play a melody-line instrument often think that piano music looks bad - two staves, two clefs, lots of notes at the same time.
Organ music is usually written on three staves (there's an extra bass clef stave for the pedal part), and there are cryptic markings (giving advice/instructions about registration). And if it's been used, there'll be lots more pencil markings added (and quite possibly little bits of post-it note).
When I say cryptic, I mean things like -SP (disengage the swell to pedal coupler), +16OD (add the 16' open diapason), GR (French for Great and Swell together).
I once page turned for someone practising for a recital. I could recognise most of what was written - occasional bits of fingering, the odd sharp or flat marked, piston numbers (inside different shapes, to show which ones belonged to which organ) all over the place and other registration markings. But throughout the music were regular occurrences of "WA". I couldn't for the life of me work out what it meant and I didn't want to sound stupid by asking, but curiosity got the better of me, so after he was finished I asked about it. Turned out it meant "Westminster Abbey" and was flagging up registration changes for a recital he'd played there. I'd been thinking it was some organ term I hadn't come across before (or had come across but wasn't recognising the shorthand for).

One thing that I think might be helpful to point out is that, although they both have keyboards, are used to play polyphonic music (lots of notes at the same time) and have music written on more than one stave, piano and organ aren't really related instruments. Most organists learn piano (to some standard or other) before beginning the organ, and you do need keyboard facility to play either instrument. But the feel of the instrument is very different, as is the way you think about what you're doing.
The piano is a percussion instrument. When you press a key, a hammer strikes a taut string to produce a sound. You create lots of subtleties of volume, tone, etc by how you press the keys (in much the same way as a percussionist varies the way they strike a drum or a mallet instrument).
The organ is a wind instrument. Sound is produced by columns of air vibrating in pipes, or by air making a reed vibrate in a resonating pipe. So you shape your phrases in much the way that you would on a woodwind instrument or when singing. You need to let the instrument "breathe", or you get a solid wall of sound. You can't stress a note by hitting the key harder, so if you want a note to stand out, you have to create a little bit of space around it, by tweaking the duration of other notes.
My organ music tends to gets lots of little tick marks pencilled in, just like my flute music, and they indicate the same thing in both cases - where I'm going to take a breath.

T.

[Teigr]

If anyone wonders why I started this thread, take a little look at:
http://forums.abrsm.org/index.php?showtopi...26&st=98895
That's a page from the CISD thread that includes a couple of posts where I tried to explain a little bit about stops. I'm going to try to make it less confusing this time around, though.

Hopefully the stuff on this thread so far has laid a good foundation for what's to come.
But I'm going to start by straying away from organs for a moment, and try to say a bit about the harmonic series.
The catch here is that I've got a physics/maths/eng background, so I tend to dive headlong into physics jargon. I'm going to try hard not to, but I might need some help with trying to get this into terms that anyone can understand no matter what their field is.


When you hear a sound, you're hearing vibrations in the air, which hit your eardrum, are transferred into your inner ear and are decoded by your brain automatically.

What makes those vibrations in the air is something else vibrating (and jogging the surrounding air), or something which makes the air itself vibrate in a controlled way.

String instruments are good to use as examples, because you can see what happens. If you pluck a string you can see it vibrate.
Look carefully and you'll see if moves the most in the middle, and less at the ends (because they're fixed to the instrument).

The obvious ways to change the pitch of a note on a stringed instrument is to vary the thickness or the length of a string. The thicker strings give lower notes. And if you shorten a string (by pressing down against the fingerboard), you get a higher note.
You can also get a higher note if you tighten a string - that's how you tune a violin or similar, by adjusting the tension in the strings.

But there's another trick you can use. Get a friend with a guitar to show you this, or borrow one and try it for yourself.
Find the 12th fret (strip of metal across the fingerboard) - count starting from the end where the machine heads (tuning pegs) are. This will give you the mid-point of the strings.
Pluck a string and listen to the note. Get the sound of it fixed in your head.
Then hold the string down so that it's touching the fretboard just behind the 12th fret (your finger should be to the side where the machine heads are). The active length of the string now goes from that fret to the bridge (the place where the strings attach to the body of the guitar). Pluck the string again, and you should hear a sound that's an octave higher than you got from the open string.
Now the clever bit. Touch the string very lightly with one finger, directly over the 12th fret (so if you pressed down, you'd touch the fret itself). But don't press down. Now pluck the string. You should again hear a sound an octave higher than the open string. (It can take a bit of practice to find the knack of making this work.)

What you've done here is, instead of halving the length of the string which can vibrate, you've halved the length of each standing wave (vibration) on the string. Instead of the string vibrating as one length, it's now vibrating in two separate sections. You should see that the bits that move the most are the middle of each half of the string, while the two ends and the bit where your finger rests are still.
So it's now behaving a bit like 2 separate strings, each half the length of the original.

If you try the same trick at the 5th fret, the fretted note will be a perfect 4th above the open string, but the note when you just touch the string very lightly should be 2 octaves above the open string.

When you halve the length of a string, the sound goes up by one octave.
The 5th fret is one quarter of the way along the string, so when you fret (press down just behind the fret) there, you're not going up a full octave, as 3/4 of the string is vibrating.
But when you do the thing with the light touch, you're encouraging the string to set up 4 equal length standing waves (one between your finger and the top of the string, the other three to match it, down the rest of the string). So it's behaving rather like 4 strings, each of which is a quarter the length of the original string.
Making a string a quarter of its original length with raise the pitch by 2 octaves, because you've halved it, then halved it again.


You've probably seen a tuning fork labelled A=440.
That means that it gives the note we call A, and the vibrations associated with it are 440Hz (hertz, or wiggles per second).
Anything vibrating at 440 Hz will sound like an A, but the A you get from a violin sounds very different from the one you get from an oboe.

This is because the sound the instruments produce aren't a pure vibration of 440 wiggles per second.
The main sound is that, but there are a whole bunch of other waves as well. You can't see them when you look at the string, because the main one is the biggest.

Quick tangent - pluck an open string very gently. You can see it vibrate, but the bit that moves the most isn't actually moving very far. It should sound fairly quiet.
Now pluck it harder. It should sound louder and the amount it wiggles by should be bigger.
The "width of the wiggle" is called amplitude.

Back on track - the 440Hz wave has the biggest amplitude. The smaller waves that are happenning along the string have much smaller amplitudes, so your eye can't see them. They're like the waves you set up when you touched the string very lightly and plucked it.
Your ear hears them though. But your brain doesn't tell you that you're picking up a bunch of shorter waves (which would be higher pitched notes if you heard them by themselves). Instead, it interprets them as part of the overall timbre (type of sound) of the main A440 note.

Different instruments produce different collections of those extra "invisible" high notes - called overtones or harmonics, and that's why they all sound different even when playing the same note.


Physics jargon that you'll find useful:

amplitude - the width of the wiggle.
wavelength - the length of the wiggle
frequency - wiggles per second

Big amplitude = loud sound. Small amplitude = quiet sound.

Wavelength and frequency are (inversely) related - the shorter the wiggles, the more times they wiggle per second, and vice versa. We describe the pitch of a note in terms of frequency. But we tend to change the frequency by messing around with the wavelength (shortening strings, covering finger holes, opening valves to lengthen tubes, etc).

There's some complicated-sounding stuff about sine waves and how the wave you see on a stopped string is actually half a complete wavelength. Ignore that for now - I'm mentioning it just to reassure the physics folk. I'll try to explain it in very easy terms later (it becomes relevent when you want to understand how stopped pipes work).


The overtones that you can get aren't random. They come in a predictable pattern, called the harmonic series. I'll go into that more later when I try to explain how all this stuff applies to organs (the basic idea is that different length pipes work like different length strings).
The organ's party trick is that you can manipulate which overtones you get from it, thus changing the sound of a note. There are special stops that are used to do that, and they're known as "mutation stops" because you use them to modify the sound of other stops.

I'm going to leave it there to give people a chance to make corrections and ask questions about the physics, before getting into how this applies to the organ.

T.

[sarah-flute]

amplitude - the width of the wiggle.
wavelength - the length of the wiggle
frequency - wiggles per second

(IMG:style_emoticons/default/laugh.gif) Well done, you explained something related to physics in a way I can totally understand (IMG:style_emoticons/default/biggrin.gif) consider me impressed...

*awaiting next installment*

[John Robinson]

Thank you, Teigr, for your very gracious response.

Actually, I was rather hoping that you might contradict my 'very old indeed' statement!

Perhaps you are right about taking up the organ upon retirement. I understand that the only real way into this is to befriend a local organist or vicar. I don't know how I'd go about this, though, as I am an atheist and refuse to be less than honest about this. I suspect that, once learning has begun, I would be asked to play for services, etc.

John

[Teigr]

That's something else that came up in the conversation in CISD - how can you learn the organ if you don't go to church and can you learn if you have a different faith?

Here's what I said there:

"Organists tend to be fairly self-selecting and often have a church background of some sort. A lot are former choristers. A lot of the repertoire is church music and most playing opportunities are for church services.
Some organists are practicing Christians, but some aren't (though they tend to have some church background and remain tolerant of Christianity rather than hostile to it). There's absolutely nothing to stop someone with no church involvement or of another faith from learning the organ, other than the fact that most people in those situations probably wouldn't want to - either because they don't like that sort of music and environment or, most likely, because lack of exposure to it means they've never had a chance to become enamoured of it.
Churches tend to have a realistic approach - there's a shortage of organists and if someone can do the job, they'll get it, regardless of personal beliefs. (OK, there'll be /some/ churches that take a different stance, but most are more interested in what you can do than what you believe.)"

Now, I was talking about playing a church organ (which was the context of the conversation).
I'm sure diapason can say something about routes into playing theatre organs, and there's always the option of having a digital instrument at home.

Anyone who is outright offended by Christianity or who won't set foot in a church isn't going to want to learn to play a church organ. But if someone of another faith, or no faith, or of a different denomination to the church they want to play at (there have been very high profile appointments of C of E organists to Catholic posts and vice versa), or who was raised Christian but isn't a practicing Christian, or /whatever/ doesn't mind practicing in church, it's extrememly unlikely that it's going to be an issue as far as the church/vicar/organist is concerned.
If a church lets you practice there, it's fair that you will play for them occasionally, but as long as you don't mind sitting through a church service and playing what's required, they probably aren't going to care what you do or don't believe.

There have been arguments before about whether or not a non-Christian should hold a church appointment. We are NOT going to have that argument in this thread! (Neither are we going to have the one about whether a Christian who is also an organist should accept payment for playing for Sunday services.)
If people want to get into those debates, they can resurrect old threads or start new ones.

Whether or not everyone agrees that it's OK, the situation on the ground is that most churches probably aren't going to ask or care about the personal beliefs of an available organist.


If you're practicing on a digital instrument at home, but taking lessons with a church organist, it's even less likely to be an issue. You'd simply be a paying pupil, attending lessons.

I certainly don't think anyone should be anything other than honest about what they believe. But faith (or lack thereof) is not going to be a barrier to learning the organ (you can probably find a teacher with a digital instrument at his home as well as having one yourself, so it's possible to learn without going into a church at all) and is unlikely to be a barrier to practicing in church and playing for occasional services if you are willing/able to do so.

T.

[John Robinson]

Oh no! I certainly do not detest church music. On the contrary, I like most of it very much - but not the 'happy clappy' stuff.

Anyway, I shall desist with apologies, as this is rather off-topic.

John

[maggiemay]

Oh no! I certainly do not detest church music. On the contrary, I like most of it very much - but not the 'happy clappy' stuff.

John

Oh - you certainly are not alone there.

By the way, I was faintly appalled to learn that you consider a certain age to be old ...

(wonder if you can guess why ...!) (IMG:style_emoticons/default/wink.gif)

[Teigr]

One big issue with a lot of modern worship songs, as far as organists are concerned, is that a lot of them simply don't work very well on the organ. Just like a lot of tradition hymns really don't work well on guitar.

Sure, there's personal taste as well, and we might not like them. But even if we like them, we tend not to like playing them on the organ.

This coming Sunday is Family Service at my local church. The kids are in for the whole service and it's very much geared to them. I've seen the music list and it's almost all worship songs and kiddie songs - the sort of list that a duty organist would dread seeing. So, as usual for Family Service, there's no organist on duty and the music group (currently one guitar and one flute) will play. There's one hymn at the end of the service, so if I'm feeling very brave I might play that one on either the piano (the music group is right next to it) or the organ (and if I play it on the organ, I'll probably play a voluntary as well), instead of on flute.

Sometimes organists do find themselves faced with worship songs, but a lot of churches (at least, the sort of churches that use worship songs) have a piano and/or a music group available and try to match the style of music to the instrumentalists on duty (or vice versa).

So, for John or anyone else thinking about taking up the organ and willing to play traditional church music but dreading the prospect of worship songs, I can't promise that you'll never be asked to play one, but on the whole people tend to be aware of what works on the organ and what doesn't, and will usually try to organise music lists accordingly.

The other option is to choose which church you form an association with according to the style of music employed there. Unless you live somewhere quite remote, chances are you'll be able to find several churches fairly near to you, with different styles of worship.

T.

p.s. Quick jargon-bust for anyone who needs it - a voluntary is a piece of organ music played at the end of a service. Sometimes also used to refer to an organ piece played before or during a service, but people will then tend to specify "opening voluntary" or whatever. If you hear "voluntary" with no qualifier, chances are that the person means a closing voluntary.
Another name for a closing voluntary is postlude. Music before the service may be called a prelude and music in the middle (perhaps played during Communion, or to fill in during some other part of the service) may be called an interlude.
A hymn sung while the clergy/choir procession is entering is called a processional - one while they file out is called a recessional. You'll also hear people use the terms for organ music played during processions.

edit: Anyone know the derivation of postlude, etc. - does the "lude" bit come from ludo/ludere (I/to play) or is that just a co-incidence?

[John Robinson]

Oh no! I certainly do not detest church music. On the contrary, I like most of it very much - but not the 'happy clappy' stuff.

John

Oh - you certainly are not alone there.

By the way, I was faintly appalled to learn that you consider a certain age to be old ...

(wonder if you can guess why ...!) (IMG:style_emoticons/default/wink.gif)

As all men are aware, ladies do not age beyond 21, and even if they do they remain quite charming.

John

[sarah-flute]

By the way, I was faintly appalled to learn that you consider a certain age to be old ...

(wonder if you can guess why ...!) (IMG:style_emoticons/default/wink.gif)

As all men are aware, ladies do not age beyond 21, and even if they do they remain quite charming.

...all men with an intact survival instinct... (IMG:style_emoticons/default/wink.gif) (IMG:style_emoticons/default/smile.gif)

[maggiemay]

By the way, I was faintly appalled to learn that you consider a certain age to be old ...

(wonder if you can guess why ...!) (IMG:style_emoticons/default/wink.gif)

As all men are aware, ladies do not age beyond 21, and even if they do they remain quite charming.

John

oooh! (IMG:style_emoticons/default/biggrin.gif)

The other option is to choose which church you form an association with according to the style of music employed there.

(IMG:style_emoticons/default/blush.gif) (IMG:style_emoticons/default/wub.gif) (IMG:style_emoticons/default/wub.gif)

[Teigr]

I said before that the overtones aren't random.
This is because the string is forced to remain stationary at each end (where it's in contact with the bridge and nut of the guitar). So the default wiggle length is that of the string itself. You can't get one and a half wiggles, because the midpoint of each wiggle is where it moves the most, so you can't have a half-way point like that occurring somewhere the string is held still.
So any waveform occurring on the string needs to be one where the length of the string is divided into a whole number of shorter waves, with no bits left over.

So, the first one you can make is by halving the string, which gives the octave.

Then you can divide it into 3, which gives you an interval of a 12th.

Dividing into 4 (which you've already seen on the guitar), gives the 15th (two octaves).
Dividing into 5 gives you the 17th (two octaves and a 3rd) and into 6 gives you the 19th (two octaves and a 5th).

The further up the series you go, the closer the harmonics get to each other.


In most instruments, the design of the instrument controls which harmonics are most noticeable and which are damped down, which in turn affects the timbre of the sound.


On some instruments you can force a harmonic to sound in place of the fundamental (default) note - you've seen how that works on the guitar already. By resting your finger on the string you force it to vibrate in shorter wavelengths.

On some instruments you do something similar by changing the air-flow. When you change register on the flute (between two notes with identical fingering), you're using harmonics.

The best instrument to hear this in action is the bugle (or cornet or trumpet or similar) - find yourself a friendly cornet player and ask for a demo of how many notes he can play without touching the valves.
I can manage C, G, C, E and (on a good day) G, but I'm rubbish at brass. Your friendly cornet player should get that G and probably the B flat and the C above, possibly more.
Leaving the valves alone means that you're not adjusting the length of the tube (changing that would change the fundamental note). You're doing it all with harmonics.

You might have spotted that the first pair of notes aren't an octave apart. It's very difficult to get the true fundamental on a cornet. I can't do it, and it's not required for normal playing. A brass player friend of mine has managed it, but can't do it on demand.

With Rememberence Sunday coming up, you'll probably hear the Last Post played. It's a bugle call, so the whole thing can be played on a cornet/trumpet without using the valves.



On the organ, if you add a mutation stop, you can reinforce one or more harmonics of your choice, which changes the timbre of the sound.
Stops are labelled with either the length of the pipe or the interval it produces relative to an 8' pipe (which is the default length).

So, let's start with one particular mutation stop as an example.
The pipe length is 2'8", which is written as 2 2/3.
This is equal to one third the length of an 8' pipe, so it gives a sound a 12th higher (octave and a perfect 5th).
Such a stop is often called Nazard or Twelfth.

If you have access to an organ, try this:
Look at the drawstops and find a stop labelled 2 2/3 Nazard (or 2 2/3 Twelfth) and note which division it's on.
Draw that stop and an 8' stop on a different division.
Play a C on the manual that you've drawn the nazard on. Listen to the sound.
Now use the other manual to try to compare it to the C you get from an ordinary 8' pipe.
Then, on that manual, play the G an octave and a half higher, and compare that to the C you're getting from the nazard.
You're not going to want to use a nazard by itself to play hymns!

Now, try drawing an 8' open diapason, a 4' principal, and 2 2/3 twelfth all on the same division. Play a note.
Try taking away the twelfth and seeing what it does to the sound.

That's what mutation stops are for.

If you add too many of them without beefing up the 8' sound, you can overwhelm the basic note.
And, if you experiment a bit with some of the mutation stops, you'll find that they can be rather uncomfortable to listen to.
But when you have a solid combination with plenty of 8' and some 4' stops, you can play around with the very squeaky ones fairly safely. With enough bigger stuff to give a stable foundation, the little stuff is interpreted by your brain as a change to the timbre of the fundamental note, rather than as a separate squeak.

Some stops are called mixtures. Rather than having separate stops for, let's say, the 19th and 22nd, you might find a stop labelled Mixture II 19.22 - meaning a mixture of 2 harmonics, the 19th and 22nd.
Some organs have stops labelled Mixture II, Mixture III, etc. but with no indication of which intervals are in the mixture. (You can work it out, either just by ear, or by sounding the mixture on its own on one manual and comparing it with an 8' stop on another manual.)

So, stops showing numbers that are powers of 2 or which feature fractions refer to the length of the pipe, while ones labelled with 2 or more numbers in the teens and twenties are referring to the intervals above the fundamental.


A combination is a selection of stops, chosen by the organist to give a particular sound.

A church organist will have experimented with various combinations on "his" instrument, chosen some which he considers particularly pleasing and/or useful and programmed the organ to remember them. The thumb pistons mentioned earlier in the thread are used as "shortcut keys" to those combinations. Some organs have toe pistons, which serve the same purpose but are operated by the feet. You press a piston and several drawstops move.
A divisional piston controls stops for a single division. A general piston controls stops across the whole instrument.
Some organs have an electronic system that allows multiple sets of combinations to be stored. You select a particular memory channel (by pressing little buttons) and those LED numbers (see the My Organ thread for a picture) change. A church with several organists may assign each of them a memory channel on which to set up their own piston settings.


More details about particular mutation stops to follow.

T.

[John Robinson]

May I congratulate you, Teigr, on some excellent pieces of writing thus far.

I look forward to the next instalment on mutations. Personally, not having access to an instrument, I should be very interested to learn about the sound of individual mutations (in combination with unison stops, of course), and I hope you can extend the explanation to less common ones such as sevenths, ninths, and possibly even rarer examples such as elevenths and thirteenths. If you could provide sound samples or, at least, point us towards any online samples you know of I should be very grateful.

Indeed this prompts me to suggest that you could perhaps, when this thread is completed, extract all the pertinent information and make a separate web site of it, perhaps including pictures and sound samples.

I have a number of textbooks on the organ which provide a wealth of information, yet none are written for beginners. I feel that what you have written so far could form the basis of an excellent work which would fill this niche.

John