Author Topic: No__81___Basic organ stops explained  (Read 698 times)

Peter Anderson

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No__81___Basic organ stops explained
« on: January 04, 2018, 03:15:02 PM »
There is another Peters Pearl, No 83 that deals with how a pipe organ works, and you can open that topic in a new window, by clicking this link:

http://www.ar-group.org/smforum/index.php?topic=3012.0

I wonder how many of us has had the opportunity to play a large pipe organ.     If not have you ever considered how you would go about selecting some of those pistons or stops to achieve an adequate sound?

In this Pearl we look at the types of speaking stops available and other non-speaking stops to harness their power, and try to describe what they do and how to combine them.

This should be of interest to us all, and especially as we compare how Yamaha has incorporated these attributes into our AR organs.

Then, if you ever get the chance to play the Blackpool Tower theatre organ, or some other cinema organ like it, we will follow that, with making sense of the vast number of tabs that comprise that daunting horseshoe layout of cinema and theatre organs.     (This won't be started until the Spring.)   
Suffice to say at the moment, that unlike traditional pipe organs, for about 100 years all cinema and theatre organs have been built to a common industry standard layout!    How considerate of all the manufacturers is that!

That probably explains how those professional organists seem to just sit at a cinema or theatre organ they have never seen before and boldly flip the tabs up and down all over the place, with such apparent ease.   The answer is that the 'dashboard' of each one is identical in its basic form, far more than any car you want to pick!    We all know that some things like the horn, or wiper controls tend to be in a similar position, but that can't be said for most other controls, knobs, levers and switches, let alone the dials, so we have to explore a different vehicle and familiarise ourselves to a new layout.

More anon, but that should whet your interest.

The following Replies were originally posted at one Reply per week.

Peter

john

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Re: No__81___Basic organ stops explained
« Reply #1 on: January 07, 2018, 03:18:14 PM »
I got saddled with playing our local church organ which I did for about 8 years. I'm not good and did all of the usual errors to start with - play too few versus, play too many, weddings were something totally new.

The one thing that astounded me, we had a visiting organist for a wedding, she played all of the usual wedding music and I was bell ringing. When the bride entered the church the traditional wedding march was played and the bass notes were so low you could only feel some them rather than hear them. I knew the organ very well and no stops would produce sound like she achieved. I went to have a chat afterwards and the notes were achieved by playing two bass pedals together, the resultant beat frequency was the low note we were feeling. I couldn't master the technique, nor do I remember how she worked out the notes, it was an incredible effect though.

Peter Anderson

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Re: No__81___Basic organ stops explained
« Reply #2 on: January 08, 2018, 09:44:57 AM »
Fascinating, John.   I don't profess to know about these intricate accomplishments, but I will endeavour to find out more.
This Pearl will deal with the basic features of the organ, especially the stops, in order to give members a wider understanding of them, and enable any of us to make a sensible start if given the opportunity to actually play one.
Thank you for your input,
Peter

Here is more information, that I promised, on this subject:

Re the organ question, here is a link I found which may add some detail

http://www.organstops.org/r/Resultant.html

The technique appears to be called Resultant Bass

Basically if you play a bass C pedal together with the G a fifth higher you can get a resultant sound 1 octave below the original bass C.    So if you use a 16’ pedal stop you effectively generate a 32’ pedal stop.  Some use the technique very occasionally, but it is very dependent on the sound quality of the original 16’ stop, and generally the resultant sound is very ‘muddy’ and unconvincing    I don’t think we can create this effect on the AR as our pedals are not polyphonic.
Perhaps some members who have other organs with polyphonic pedals might like to experiment and advise us of the results.

Peter

Peter Anderson

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Re: No__81___Basic organ stops explained
« Reply #3 on: January 10, 2018, 11:23:48 AM »
What are all those stops for on Pipe organs?

We all know that orchestras comprise a variety of instruments, ranging from large and small, loud and soft, brash and gentle, etc.     All of these single instruments have one tonal quality each.      However, combined together with the right balance, they can produce some stunning musical renditions.

The organ, beside being the largest musical instrument, has not just one, but many tone qualities.    As you select registrations for your AR performances, you are master of your own music ensemble.    You become the conductor of your very own orchestra, for in the Yamaha AR organ you can choose an amazing variety of different sounds, which you can combine together.

There are some very good Organ Voices that electronically mimic, quite accurately real instruments.

But, in this posting I want to explore the Basic Stops that you will find on many pipe organs, with most of them also available to us on our AR’s.

Most Classic or Church Pipe organs have buttons, tabs, pistons or knobs that are called Stops.

What is an organ Stop?   
An organ stop (or just stop) is a component of a pipe organ that admits pressurized air, known as wind, to a set of organ pipes.

Most stops will operate just one group of similar pipes in an organ, but some have multiple functions and some can control a complete set of individual stops.     But we’ll cover most of these areas later on.

I don’t know why they are called stops, but it may have derived from their function of shutting off the flow of air to the pipe(s) they control.     i.e. stopping the wind and therefore the sound.

In the next Reply we look at the mechanical action of Keys and Stops, which is the mechanical essence of the pipe organ.

Peter

Footnote
The largest pipe organ ever built, based on the number of pipes, is the Boardwalk Hall Auditorium Organ in Atlantic City, New Jersey, built by the Midmer-Losh Organ Company between 1929 and 1932. The organ contains seven manuals, 449 ranks, 337 registers, and 33,114 pipes.   
No-one is absolutely sure just how many pipes there are, so this an estimate.

The main auditorium is 487×288×137 feet (148×88×42 m) with a floor area of 140,000 square feet (13,000 m2), giving a volume of 5,500,000 cubic feet (160,000 m3).   Consequently, the organ runs on much higher wind pressures than most organs in order to achieve a volume loud enough to fill the hall.
The organ has four entries in Guinness World Records, including "Largest pipe organ ever constructed", "Largest musical instrument ever constructed" and "Loudest musical instrument ever constructed", and holds several records in the organ world. It is one of only two organs in the world to have an open 64-foot rank, and the only organ to have stops voiced on 100 inches of wind pressure (about 3.6 psi). Its console features seven manuals


Unless you know of a larger one, of course.

Peter Anderson

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Re: No__81___Basic organ stops explained
« Reply #4 on: January 15, 2018, 10:49:57 PM »
Re John's comment above about playing 2 pedals together to create a deeper bass note, here is more information for you.     I have also added this to my earlier Reply, to keep it in sequence for others reading through this later.


Re the organ question, posed by John in an earlier Reply, here is a link I found which gives more information:

http://www.organstops.org/r/Resultant.html

The technique appears to be called Resultant Bass

Basically if you play a bass C pedal together with the G a fifth higher you can get a resultant sound 1 octave below the original bass C.    So if you use a 16’ pedal stop you effectively generate a 32’ pedal stop.  Some use the technique very occasionally, but it is very dependent on the sound quality of the original 16’ stop, and generally the resultant sound is very ‘muddy’ and unconvincing    I don’t think we can create this effect on the AR as our pedals are not polyphonic.
Perhaps some members who have other organs with polyphonic pedals might like to experiment and advise us of the results.

Peter

Peter Anderson

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Re: No__81___Basic organ stops explained
« Reply #5 on: January 17, 2018, 09:53:29 AM »
The controls available to the organist, including the keyboards, couplers, expression pedals, stops, and registration aids are accessed from the console, which is the bit the organist sits at and is very visual.     The organ itself containing the pipes, windchest and blower, is housed separately, but often has decorative pipes around it.     The console can either be built into the main organ housing or detached from it.     In this latter case, it is called, surprise, surprise, a detached console.

A pipe organ contains two actions, or systems of moving parts.     When a key is depressed, as I’m sure you know, the key action admits wind into a pipe. The stop action allows the organist to control which ranks are engaged.   

An action may be mechanical, pneumatic, or electrical (or some combination of these, such as electro-pneumatic action).     The key action is independent of the stop action, so allowing an organ to combine a mechanical key action along with an electric stop action. 

A key action which physically connects the keys and the windchests is a mechanical action and is known as a tracker action, because connection is achieved through a series of rods called trackers.       When the organist depresses a key, the corresponding tracker pulls open its pallet, allowing wind to enter the pipe.


Here is a line drawing of how this works





Tracker action has been used from antiquity to modern times.     Despite the extra effort needed in playing, many organists prefer tracker action because of a feel and a control of the pipe valve operation.     Before the pallet opens, wind pressure augments tension of the pallet spring, but once the pallet opens, only the spring tension is felt at the key.     This provides a "breakaway" feel.

Pipes are arranged by timbre and pitch (more of this to follow) into ranks.     
A rank is a set of pipes of the same timbre, but multiple pitches, with one for each note of the keyboard, and mounted, usually vertically onto the windchest.     
The stop mechanism admits air to each rank.    So for a given pipe to sound, the stop governing the pipe’s rank must be engaged, and the key corresponding to its pitch must be depressed.    Ranks of pipes are organised into groups called divisions and each division is generally played from its own keyboard.    This is why the keyboard, or manual, is also often referred to as a division.

In a mechanical stop action, each stop control operates a valve for a whole rank of pipes.   
When the organist selects a stop, the valve allows wind to reach the selected rank.       This control was at first a draw stop knob, which the organist selected by pulling (or drawing) toward themself.        This is the origin of the idiom "to pull out all the stops".     More modern stop selectors, used for electric actions, are tilting tablets or rocker tabs, which are commonly found on cinema organs.

This diagram shows how a stop allows wind to access the pipe rank chambers






In the next Reply we begin to explore these organ stops more thoroughly.   

Peter

Peter Anderson

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Re: No__81___Basic organ stops explained
« Reply #6 on: January 24, 2018, 09:38:56 AM »
Organ Stops

Just as each single instrument’s sound and tonal quality are influenced by the size and length of the pipe, or string that produces the note, so in an organ the sounds and their tonal qualities are controlled by the size and length of the pipes in the organ.

These pipes are made from either wood or metal and are controlled by stops on a pipe organ.     In an electronic organ, where the pipe sound and tone is generated, and then amplified through built in speakers (to mimic the pipe organ) they, too, are controlled by stops, but they need only be small electric switches or buttons.     This is what we have on our AR organs.    But I will continue to refer to them simply as stops.

As mentioned very early on, each stop controls one rank of pipes, to produce sound, and the names of these stops reflect not only the timbre and construction of that stop, but also the style of the organ in which it resides.   For instance, the names of an organ built in the north German Baroque style, generally will be derived from the German language, while the names of similar stops on an organ built in the French Romantic style will usually be French.    This explains why there are some incredible stop names.   

Stop names are not standardized, so two otherwise identical stops from different organs may have different names.     The label on the stop knob indicates the stop’s name and it’s pitch in feet.

There are other stops, which are labeled different to this, but we will explain those in future Replies.

On traditional pipe organs, stops fall into 2 main categories.

They are

                       Speaking           &

                       Non-Speaking             stops.


You will not be surprised to learn that non-speaking stops do not produce any sound.

The speaking stops, that actually do produce sound, are divided into 4 basic families.

They are:

Principal          also known as    Diapason

Flutes

Strings

Reeds


The Principal or Diapason are the most important family.

The first 3 of these families, comprising the Principal, Flutes and Strings are often referred to as the Foundation Stops of the Organ.

These organ pipes are called flue pipes and they produce sound by forcing air through a flipple.   This is like a recorder – you probably all had a go at one of these in your schooldays.

Whereas reed pipes produce their sound via a beating reed, like that found on clarinets and saxophones.

To use them effectively we need to remember 3 basic things about each stop.

We need to remember these 3 things about each stop

                       Family

                       Pitch

                       Volume



So we ask questions like….

Which Family               Does it sound like a flute or a string?    etc.

What Pitch                  What is its relative highness or lowness?

Its Volume                   What is its loudness or softness?


Each speaking stop represents a row or set of pipes, with all of them in that set, producing the same tone quality.   There is one pipe, in every set of pipes, for each key, on each of the keyboards and the pedal board.

In the following Replies we explore the basic sounds of each of these families of stops.

Peter

Peter Anderson

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Re: No__81___Basic organ stops explained
« Reply #7 on: January 28, 2018, 02:35:32 PM »
Just before we begin to explore these organ stops, you might like to take a look at this list of Stop names.

Click this link to open in a new window,  Wikipedia, List of Pipe Organ Stops:

https://en.wikipedia.org/wiki/List_of_pipe_organ_stops

There is also facility on this page to listen to audio of the stops, which will enable you to appreciate what sound the stop creates.

Peter

Peter Anderson

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Re: No__81___Basic organ stops explained
« Reply #8 on: January 31, 2018, 11:05:30 AM »
Each Family of Stops         has 3 common characteristics

1.      Tone Quality


The Tone Quality of the Principal or Diapason family, is the basic sound of the organ.     
The  higher ranges have brightness, while the lower ranges have a sombre quality.

The many members of the Flute family express serenity and quietness.      They are often blended with other stops.      Again, their upper range of brightness, turns to a sombre sound in the lower ranges.

The thin soft sounds of the String stops, sound akin to stringed instruments, being delicate in the higher range and more sombre in the lower range.

Also - The Voix Celeste, (pronounced - Suh-Lehst) which is an undulating stop, is a row of twin pipes of the same tone quality. with one of them being tuned slightly sharper.


The Reed stops control pipes that have a reed inserted at their mouths.       
They sound similar to the brass and woodwind sections in an orchestra.
They add emphasis throughout the whole register.
The louder reeds are powerful and assertive.

Reed stops include such names as     
     trumpet       clarinet         oboe         horn         tuba.


Also The Vox Humana stop, (somewhat) resembles the sound of the human voice, hence its name.

In the next Reply we turn our attention to the second characteristic of the stops.

Peter

Peter Anderson

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Re: No__81___Basic organ stops explained
« Reply #9 on: February 07, 2018, 11:06:33 AM »
In addition to its tone quality, each organ stop has a second important characteristic, so we now consider…

2     Pitch

The basic pitch comes from a pipe about 8ft in length, which is why a stop sounding this note is known as an 8ft stop.    Any note played with just an 8ft stop selected, will always be the equivalent of that same note played on a piano.

These diagrams may help.

With an 8’ stop selected, then Middle C played on the organ sounds the Middle C note.



With a 16’ stop selected, then Middle C played on the organ sounds the C an octave lower than Middle C.



With a 4’ stop selected, then Middle C played on the organ sounds the C an octave higher than Middle C.



With a 2’stop selected, then Middle C played on the organ sounds the C two octaves higher than Middle C.


In the next Reply we look at the third Characteristic of the stops.

Peter

Peter Anderson

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Re: No__81___Basic organ stops explained
« Reply #10 on: February 14, 2018, 11:04:00 AM »
3   Volume      is the third characteristic of the Stops.

The volume with respect to other stops gives obvious variation and all of them are controlled in unison, by what we call the expression pedal.

Strictly this was originally called the Enclosure or Expression pedal.        It refers to a system that allows for the control of volume without requiring the addition or subtraction of stops.    In a two-manual organ with Great and Swell divisions, (also called manuals, or keyboards),  the Swell will be enclosed.     In larger organs, parts or all of the Choir and Solo divisions may also be enclosed.     The pipes of an enclosed division are placed in a chamber generally called the swell box.     At least one side of the box is constructed from horizontal or vertical palettes known as swell shades, which operate in a similar way to Venetian blinds.        Their position can be adjusted from the console.     When the swell shades are open, more sound is heard than when they are closed.      Sometimes the shades are exposed, but they are often concealed behind a row of facade-pipes or a grille.

The most common method of controlling the louvres is the balanced swell pedal.  This device is usually placed above the centre of the pedal board and is configured to rotate away from the organist from a near-vertical position (in which the shades are closed) to a near-horizontal position (in which the shades are open).     

An organ may also have a similar-looking crescendo pedal, found alongside any expression pedals.       Pressing the crescendo pedal forward, cumulatively activates the stops of the organ, starting with the softest and ending with the loudest; pressing it backwards reverses this process.

But for the AR, with just one expression pedal, we can still alter the volume of each individual ‘Voice’ that we choose, and adjust their balance to one another.    So we can generate a greater variation of volume between the ‘stops’ than is possible on most pipe organs.

With this in mind, let me add a comment here about what are known as Hammond Draw Bars.

We have an equivalent feature on our Yamaha AR organs with those light bars, called Flute/Tibia.   Each of these light bars are like the stops found on other organs, but have the extra characteristic of acting like a volume control.    Stops, on pipe organs, as by now you must realise, are either on or off.   That means they are either silent or at full volume.    But, in effect, we can set the draw bars to, for example, ‘half on’, or any degree of volume from off to full, by incremental steps.

Obviously you can select them in combinations, but with the benefit of adding as much, or as little, of each one as you desire, that gives us an incredible variety to the final mix of sound and volume.

For more on draw bars, take a look at Peter Pearls Nos 5 to 7, and 9 to 19, inclusive.

If you click on this link you can open the Introduction to Draw Bars, Peters Pearls No 5 in a new window:

http://www.ar-group.org/smforum/index.php?topic=1482.0

In later Replies we note how much variety we can generate in our registrations by selecting stops, but in the next couple of Replies we take a short, but I hope interesting, diversion.

Peter

Peter Anderson

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Re: No__81___Basic organ stops explained
« Reply #11 on: February 21, 2018, 09:47:07 AM »
Click this link to open in a new window,  Wikipedia , List of Pipe Organ Stops:

https://en.wikipedia.org/wiki/List_of_pipe_organ_stops

There is also facility on this page to listen to audio of the stops.

Peter

Peter Anderson

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Re: No__81___Basic organ stops explained
« Reply #12 on: February 21, 2018, 09:57:30 AM »
A slight digression, with some very simple (I hope) maths, to consider how many variations of the registrations can be obtained with just a few stops.

Suppose I have a very small organ with just 6 speaking stops on it.

Let us list all the possible combinations for drawing 1, 2, 3, 4, 5, or 6 stops, then add them up.

We obviously have 6 alternatives for our choice of the first stop, so that leaves 5 for the second choice.   So there are 6x5 ways of choosing 2 stops from our 6, which equates to 30. 
But this is technically a permutation and we want a combination.   What’s the difference?
If we choose Stop A and Stop B, we will also have another selection of Stop B and Stop A, in which case we have 2 sets the same.

So the number of ways of choosing 2 different stops from a set of 6 is:-
(6x5) divided by (2X1), which equals 15.

Does that surprise you?

Let us list all the possible combinations for drawing 1, 2, 3, 4, 5, or 6 stops, then add them up.

One stop combinations  -          6 x1  =   6
Two stop combinations  -          (6x5) / (2x1)  =   15
Three stop combinations  -          (6x5 x4) / (3x2x1)  =   20
Four stop combinations  -         (6x5x4x3) / (4x3x2x1)  =   15
Five stop combinations  -          (6x5x4x3x2) / (5x4x3x2x1)  =   6
Six stop combinations  -          (6x5x4x3x2x1) / (6x5x4x3x2x1)  =   1

Total    =    63

As you can see the individual totals fall into a symmetrical pattern, and that is logical, because choosing 4 stops is equivalent to choosing 2 stops not to pull out.

If we are interested only in the total number of combinations there is a quicker way to get the answer.
If we consider each stop in turn, they are either on or off.   
If we look at one stop there are only 2 possible results (on or off).
If we look at 2 stops together, the number of possible combinations is 2 x 2 = 4.

Now if we consider all 6 stops, the number of possible combinations is:

2 x 2 x 2 x 2 x 2 x 2 = 64.

Ah, I hear you say, “That is not quite correct”.

The reason is that the second method also includes the case where zero stops are drawn out!
So by omitting that meaningless, in our situation, alternative both results give us 63.

Yes, that’s right an organ with only 6 speaking stops can give you a choice of 63 different registrations.    I don’t know that everyone of them would be musically pleasing though!

If that surprises you see what happens with more stops on the organ.

10 stops      1,023  combinations
20 stops      1,048,575  combinations
30 stops      1,073,741,823  combinations
40 stops      1,099,511,627,780  combinations

The formula for working these figures out is 2n - 1, where n is the total number of speaking stops available.

You can see how this is derived by clicking this link:

http://www.ar-group.org/smforum/index.php?topic=3025.0

This is mind blowing, but it shows us one of the reasons that playing the organ is so fascinating.

To take a recent case that I posted last week, the organ in Odiham Parish Church has 22 stops.   This means that that particular organ has well over 1 million variations to possible registrations.   So how long would it take to work through them all?

You can view that posting by clicking this link:

http://www.ar-group.org/smforum/index.php?topic=3017.0

It means that even if you have quite a small organ, and our Yamaha AR organs are larger than most, in this respect, and even if you have been playing it for years, there are sure to be many registration combinations that you have not yet discovered.

Do our inhibitions or preconceptions of what is allowed prevent us from exploring?
Why not let your inquisitive nature loose and pull out a few of those other stops!

In the next Reply we see why the organ has the largest range of any instrument.

Peter
 

Peter Anderson

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Re: No__81___Basic organ stops explained
« Reply #13 on: February 22, 2018, 04:42:04 PM »
In Reply #3 above, we read, that the organ, beside being the largest musical instrument, has not just one, but many tone qualities.

A characteristic of the organ is the freedom that it allows the organist to build up the volume and timbre by adding, to the basic tone, stops of proportionately higher or lower pitch.
The pitch of any pipe is proportional to its length.
Thus, an 8-foot pipe will sound at normal keyboard pitch.
Whereas one of 16 foot will sound its sub-octave.
And one of 4 foot, its octave, etc.

Mutation stops (we look at these very shortly) sound at pitches corresponding to the harmonics of unison pitch, which is why they should never be used on their own, but always in combination with the standard octave pitch stops.

Pipes may vary from 32 foot long to less than 1 inch, giving the organ a possible range of 9 octaves.

This means that the range of an organ is larger than any other instrument.

Question:     How many Octaves does the Yamaha AR cover?

I am only thinking about the Upper and Lower Keyboards, which appear to be 5 Octaves.
               You can find out the actual range in the next Reply.
                     You may be surprised!

In the next Reply we get back to the subject, and take a brief look at pedal stops.

Peter

Bernard Bateson

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Re: No__81___Basic organ stops explained
« Reply #14 on: February 24, 2018, 09:38:17 AM »
There is an event at the Albert Hall London on May 15th at 7.30pm. Organ Celebration of the big organ there. A concert with many organists lasting till 11pm. I thought it might be interesting to members. Keep up the good work.