Why Does a Church Organ Have So Many Stops?
An organist does not simply play the notes. Before playing them, they have to design the instrument.
Sit somebody who has never played an organ in front of a large organ console and the first reaction is often something along the lines of:
What on earth are all those stops for?
There may be dozens of them. On a very large instrument there can be well over a hundred, arranged in ranks beside several keyboards, accompanied by couplers, pistons, pedals and other controls.
Surely nobody could possibly need that many different sounds?
But that question slightly misunderstands what an organ actually is.
A piano is essentially presented to the player as a completed instrument. Press a key softly and it sounds softly. Press it harder and it sounds louder, but the fundamental character of the instrument has already been decided for you.
An organ is different.
Before I play the first note, I can make decisions about what sort of instrument I want the organ to become.
Do I want something delicate and flute-like?
Something bright and clear?
A rich body of strings?
A powerful trumpet?
A huge ceremonial sound capable of filling a church?
Or perhaps a collection of contrasting colours which can be changed while I am playing?
That is what all those stops are for.
They are the organ's sound palette.
A Stop Is Rather Like Choosing an Instrument in an Orchestra
A useful way of thinking about organ registration is to imagine arranging music for an orchestra.
Suppose a melody is written as a line of notes on a page.
The notes do not tell us everything.
We could give that melody to:
a flute;
a violin;
an oboe;
a trumpet;
a horn;
or perhaps several instruments together.
The melody would remain recognisable, but its emotional character could change enormously.
Something similar happens on the organ.
The organist does not merely decide which notes to play. The organist decides which sounds will play those notes.
That choice of stops is called registration.
And registration is one of the aspects of organ playing that I find particularly fascinating because it sits somewhere between performance, orchestration, acoustics and technology.
What Does Pulling Out a Stop Actually Do?
On a traditional pipe organ, a stop controls a particular rank, or sometimes several ranks, of pipes.
Select a stop and those pipes become available when the corresponding keyboard is played.
On a modern electronic or digital instrument such as my Wersi Pergamon, the physical method of producing the sound is very different, but the musical principle is similar. I can select different organ voices and combinations and build up registrations appropriate to the music.
This is where an apparently intimidating console begins to make sense.
The stops are not simply there because organ builders enjoy surrounding musicians with controls.
They represent different families of sound.
The Principals — The Sound We Associate with the Organ
Perhaps the most important family is the principal or diapason family.
These are not really trying to imitate another instrument.
They are, in many ways, the characteristic sound of the pipe organ itself.
A principal at 8-foot pitch gives the normal pitch we expect from the keyboard. Add a 4-foot principal and we introduce a brighter sound one octave above. Add other suitable ranks and the sound develops into the brilliant, clear chorus associated with traditional organ music.
This is one reason the pipe organ can sound so majestic without necessarily being deafeningly loud.
It is not simply adding more volume.
It is adding structure to the sound.
Why Do Stops Say 8', 4', 16' and 2'?
One of the more mysterious things for somebody looking at an organ console for the first time is the collection of numbers.
You might see:
Open Diapason 8'
Principal 4'
Fifteenth 2'
Bourdon 16'
The numbers relate historically to the approximate speaking length of the lowest pipe in a rank.
Musically, however, there is an easier way to think about them.
An 8-foot stop sounds at normal written pitch.
A 4-foot stop sounds an octave higher.
A 2-foot stop sounds two octaves higher.
A 16-foot stop sounds an octave lower.
So if I play middle C using an 8-foot stop, I hear normal middle C.
Add a 4-foot stop and another C sounds an octave above it.
Add a 2-foot stop and another appears an additional octave higher.
That means stops are not merely different tones. They can also contribute different harmonic layers.
And that leads us to some of the more extraordinary sounds available on an organ.
Flutes — Warm, Hollow, Gentle or Bright
Flute stops are usually among the easiest colours for a newcomer to recognise.
They can be soft, rounded and gentle, although different flute stops can have very different characters.
A flute registration can be beautiful for a quiet melody.
Use an 8-foot flute by itself and it may sound simple and intimate.
Combine an 8-foot and 4-foot flute and suddenly it becomes brighter.
Add a suitable 2-foot stop and there is even more sparkle.
This is already beginning to show why registration is more interesting than simply asking:
Which stop sounds nicest?
The real question is:
Which combination produces the sound this piece needs?
Strings — A Different Kind of Softness
String stops generally have a narrower, more penetrating tone than flutes.
Names such as Viola, Salicional, Gamba or Celeste may appear.
They are not necessarily intended to fool us into believing that a violin section has somehow appeared inside the church.
Instead, they produce a tone inspired by the character of string instruments.
One particularly attractive effect comes from combining a string stop with a celeste.
The celeste is deliberately tuned very slightly away from the main stop. The tiny difference in pitch causes gentle beating between the sounds.
The result can be warm, shimmering and almost floating.
For quieter Romantic music this can be remarkably effective.
Reeds — Trumpets, Oboes and Much More
Then there are the reeds.
These are among the most distinctive organ sounds.
A trumpet stop can provide brilliance and authority.
An oboe can provide a much more delicate solo colour.
Larger instruments may contain stops with names such as:
Trumpet;
Trombone;
Clarinet;
Oboe;
Bassoon;
Cor Anglais;
Tuba.
Again, these are organ interpretations of instrumental colours rather than exact substitutes for orchestral instruments.
A strong reed used correctly can transform a passage.
Used badly, it can dominate everything around it.
That is one of the recurring lessons of registration:
More dramatic does not automatically mean more musical.
And Then We Have Mixtures
Mixtures can be particularly confusing because selecting one stop may bring several ranks of pipes into operation simultaneously.
Rather than simply adding another note at the same pitch, mixtures reinforce higher harmonics.
On their own, some mixtures can sound rather strange.
Combined with an established principal chorus, however, they can create the brilliant upper structure associated with a large organ sound.
This is a useful reminder that we should not judge every organ stop in isolation.
Some sounds exist specifically because of what they contribute to a combination.
It is a little like listening to the piccolo part from an orchestral score on its own and deciding that the orchestra would be better without it.
You have to hear it in context.
So Why Not Pull Everything Out?
This is the obvious next question.
If one stop sounds good and ten stops sound bigger, surely fifty stops must sound magnificent?
Not necessarily.
In fact, pulling out everything can produce exactly the opposite result.
The musical texture may become thick.
Individual lines may become difficult to hear.
Powerful reed stops can swamp more delicate sounds.
Too much low-frequency material can make the result muddy.
Too many high-pitched stops can make it harsh.
And, most importantly, the registration may simply be inappropriate for the music.
Imagine arranging a gentle song for full symphony orchestra, brass band, military band and cathedral choir simultaneously.
It would certainly make a noise.
It would not necessarily make good music.
Registration is about balance rather than quantity.
Registration Is Part of the Interpretation
This becomes especially interesting when we look at different types of music.
There is no single correct organ sound.
The registration that works beautifully for Bach might be completely inappropriate for a Romantic composition.
The sound needed to accompany a church congregation is different again.
And when using a modern instrument for film or popular music, the possibilities become even wider.
Playing a Hymn
When accompanying a hymn, the organ has a practical job to do.
It needs to support the congregation.
That normally means providing a clear sense of:
pitch;
harmony;
rhythm;
and musical direction.
If the registration is too soft, the congregation may lose confidence.
If it is overwhelmingly loud, they may feel that they are competing with the organ.
The number of people present matters.
The acoustics of the building matter.
The character of the hymn matters.
And the verse matters.
An organist may use a stronger registration for a triumphant final verse while using something more restrained earlier.
This is registration being used not as decoration but as part of leading the music.
Playing Bach
With Bach and other Baroque music, clarity becomes particularly important.
There may be several independent musical lines being played simultaneously.
If the registration becomes too thick, all that beautiful counterpoint can disappear into a wall of sound.
Principal choruses, carefully chosen flutes and appropriate mixtures can give the music definition and brilliance.
What matters is that we can still hear the architecture of the composition.
The registration should help us hear what Bach wrote rather than obscure it.
Playing Romantic Music
Move into nineteenth- and early twentieth-century music and the organ can take on a very different character.
Now we may want:
gradual changes of colour;
lush strings;
orchestral reeds;
rich foundations;
powerful crescendos;
contrasting divisions.
The organ begins to behave much more like an orchestra.
One section may effectively answer another.
A melody might be placed on a solo reed while another keyboard provides soft accompaniment.
The player may gradually add stops as the music builds towards a climax.
Here the registration can become part of the emotional shape of the composition.
Playing Film Music
Film music opens another fascinating area.
A traditional pipe organ is already capable of producing enormous drama, but on a modern digital instrument the available palette can become much broader.
For cinematic music I might start thinking less like a traditional organist and more like an arranger.
Perhaps I want:
a deep 16-foot foundation beneath a threatening scene;
quiet strings for suspense;
a solo flute for an isolated melody;
powerful reeds for a heroic theme;
a huge full-organ climax for a dramatic ending.
With suitable digital sounds, synthesisers and external instruments, the boundary between organ registration and orchestration becomes increasingly blurred.
That is one of the reasons I find modern instruments such as the Pergamon so interesting.
The console can become a musical control centre.
Playing Popular Music
Popular music produces another set of decisions.
A huge cathedral-style registration may be completely wrong.
Instead, the organ might need to function as part of a band.
Perhaps it provides a Hammond-style backing.
Perhaps strings sit beneath a vocal melody.
Perhaps a bright organ sound provides rhythmic chords.
Perhaps the left hand and pedals provide bass while another manual carries the main harmony.
Once again, the challenge is not:
How many sounds can I use?
It is:
What job does each sound need to do?
Three Keyboards Do Not Necessarily Mean Three Times the Notes
Another feature that confuses newcomers is the presence of several manuals — the organ term for keyboards.
A large organ might have two, three, four or even five.
That does not mean the organist is expected to grow several additional hands.
Different manuals control different sections or divisions of the instrument.
Traditionally these might include names such as:
Great;
Swell;
Choir;
Solo.
This allows contrasting registrations to be prepared simultaneously.
I might have one manual set up with a strong principal chorus.
Another could have quiet strings.
Another could contain a solo reed.
I can then move between them during the piece.
The musical equivalent would be turning from one section of an orchestra to another.
Couplers Make Things Even More Interesting
Organs also contain couplers.
These allow one keyboard to control sounds belonging to another division.
For example, a Swell-to-Great coupler might allow the Great keyboard to play the selected Swell stops as well as its own.
Pedal couplers allow sounds from the manuals to be linked to the pedalboard.
Suddenly the registration possibilities multiply enormously.
This is why an organ console can initially appear complicated.
It is not really a collection of random switches.
It is a routing and sound-design system.
The Technology Behind the Music
This is where organ playing connects particularly well with my wider interest in synthesisers, electronic music and sound design.
A synthesiser player thinks about oscillators, filters, envelopes, modulation and effects.
An orchestral arranger thinks about instrumental colour.
A recording engineer thinks about balance and frequency range.
An organist thinks about stops, pitch, divisions, couplers, balance and acoustic space.
They are different disciplines, but there is a surprising amount of common ground.
All are asking variations of the same question:
What combination of sounds will create the musical result I want?
My Pergamon makes that connection particularly obvious.
Behind the traditional concept of manuals, pedals and organ registrations is a sophisticated digital musical system capable of accessing a far wider range of sounds.
The technology has changed enormously.
The underlying musical judgement has not.
A Simple Experiment Anyone Can Try
If you have access to an organ — acoustic, electronic or virtual — try this.
Play a simple melody using just an 8-foot flute.
Listen carefully.
Now add a 4-foot flute.
Play it again.
Remove those and try an 8-foot principal.
Then add a 4-foot principal.
If available, add a suitable 2-foot stop.
Then try adding a mixture.
Finally try a reed.
Do not just ask which version is louder.
Ask:
What has changed about the character of the sound?
Is it warmer?
Brighter?
Broader?
Sharper?
More distant?
More powerful?
More suitable for a melody?
More suitable for chords?
That little exercise begins to turn stop selection from a collection of unfamiliar names into something musical.
Building a Registration Is Much Like Mixing a Track
There is another modern comparison that I think works particularly well.
When mixing recorded music, we rarely improve the track simply by turning every channel up.
A good mix creates space.
The bass has a role.
The vocals have a role.
The drums have a role.
Keyboards have a role.
Sometimes improving the mix means removing something rather than adding it.
Organ registration works in much the same way.
You can continually add stops until the sound becomes enormous.
The more difficult skill is knowing when not to add another one.
Sometimes one beautiful flute is enough.
The Stops Are Not There to Make the Organ Complicated
What appears intimidating when you first sit at an organ console eventually becomes one of the instrument's greatest attractions.
Those dozens of stops are not unnecessary complications.
They are choices.
Each one adds another colour to the palette.
And combinations of them can create thousands of different registrations.
That is why two organists can sit at the same instrument, play the same notes and produce performances that sound remarkably different.
They are not simply interpreting the notes differently.
They are effectively orchestrating the music as they play it.
The Organist Designs the Instrument Before Playing It
That brings us back to the idea with which we started.
A pianist sits down at a piano.
A violinist picks up a violin.
An organist sits down in front of something that is almost a collection of instruments waiting to be assembled.
Before the first chord, decisions have already begun.
Which manual?
Which stops?
Which pitch levels?
Which couplers?
Which solo voice?
How much bass?
How much brilliance?
How much power?
And how will all of that change as the music develops?
That, for me, is one of the great attractions of the organ.
It combines music, acoustics, orchestration, performance and technology in a way that very few other instruments can.
The enormous collection of stops is not there because an organist wants more buttons to press.
It is there because every stop represents another possibility.
And the real skill is not knowing how to turn all of them on.
It is knowing which ones to leave off.
