Using the GPO Organ

By Terry Dwyer

Which are you?:  or

* Built by Beckerath
* 3 manuals, 38 stops, 56 ranks
* Mechanical key and stop action

1 Non-organist wanting an easy life

You don’t need to learn all about the different stops, right? You would just like to use the organ in your orchestral composition to help make a big climax, or to give a religious mood (or even devilish, as used in some films). Possibly an organ solo, nothing fancy, just impressive.

 Here’s what you do:

1) A simple, good-enough result. Load the following into the Kontakt player:
  • Brustwerk all stops
  • Haupt Mix
  • Hauptwerk all stops
  • Full Organ
These are all combinations of various stops.  Try them out and see which you like – they are roughly in order of strength. If you wish, narrow it down to a few favourites.  Either way, save as a preset.  You will not want the other stops. In your compositions use one of these sounds at a time.
 
2) A more authentic sound.  This will take a little trouble, not much.  To the above list, add:
  • Baroque Plenum Ped
  • Baroque Plen Reed Ped

 When you compose and record your music, make two separate organ tracks: Organ Manuals, Organ Pedals. Allocate the manuals to one of my first list, and the pedals to one of the above pair. Into the first track you put all the organ music including the bass part, into the second track just the bass line (single notes).

This gives a more solid and more typical organ sound.  For relief you can cut out the Pedal part in selected passages, leaving the manuals to cope.

2        Organist, or non-organist prepared to learn a bit

Would you like to play around with the stops a bit, and form your own combinations? OK, let’s have a try. But first you must understand the nature of the different stops.  You should begin by reading Glenn Rudolph’s Organ Tutorial at http://www.garritan.com/OrganTutorial.html but realise that the different pitches are used for transposition purposes only in exceptional circumstances. The real reason for them will now be explained.

The different pitches of the pipes

Pipes are made in different pitches, not only at normal pitch (8 ft) but various multiples of this. These higher pipes are there to add or reinforce the harmonics of the basic pitch, and the basic pitch is always 8 ft.  You can have 8 ft on its own, or 8 ft plus 4 ft, or 8 ft + 4 ft + 2 ft, and so on, but the 8 ft must always predominate. The upper pitches are meant to blend in with the basic 8 ft more or less imperceptibly (they won’t unless the organ is well in tune) and thus their purpose is to brighten the sound, increase the volume, and change the apparent tone-colour. If the organist drew one 8 ft stop and two 4 ft stops simultaneously, this could overweight the 1st harmonic and switch the perceived pitch up an octave, leaving the original 8 ft sounding like a weak sub-octave.  Better he should draw two 8 ft stops and one 4 ft stop. But in any case the organ-builder will have ensured that the 8 ft stops are a bit louder than the subsidiary ones.

We can go higher than 2 ft: so-called“mixtures” play simple chords very high up, up to three or even more octaves above the fundamental.  Here’s a diagram showing the resulting pitches when the organists plays on 8 ft + 4 ft + 2 2/3 ft + 2 ft + mixture:

 



So what does “plenum” mean? Literally, “full”, but not quite so in practice. I will explain that in a minute, but first I want to make it clear that the above “chord” is produced by a single keypress, so that an actual chord on the organ would be a conglomeration of these “chords”.  We don’t hear them as a mess of conflicting chords, rather as a full, complex sound. It’s one way of making tone-colours.


Types of pipe

The other way different tone-colours are achieved is by the organ-builder’s choice of  pipes using different materials and shapes. There are three main classes of pipe: a) Diapasons, b) Flutes, c) Reeds. Some organ pipes attempt an imitation of another instrument, e.g. trumpet, oboe; but a Diapason is that sort of pipe which can only be an organ – it is like no other instrument (you have to hear it!). There are many diapason pipes in the GPO organ; if you want to hear one alone, play the Prinzipal, which is the German term for it.

Families

In any but a small organ the builder will have produced, probably on every manual, and even on the pedals,  three complete families (as above) at various pitches. In effect this would be Diapasons at 8 ft, 4 ft. 2 2/3 ft, 2 ft and mixture(s) of some kind; then again Flutes at the same pitches but no mixtures which are normally diapasons. However, reed stops, which are already rich in upper harmonics, need only be at 16 ft, 8 ft, and 4 ft.

16 ft stops

Now that I’ve mentioned these, let me make it clear what their function is. The best place for these octave-lower stops is in the Pedal department, where they will function just like the double basses in the orchestra – to reinforce the already existing 8 ft bass part. Organ Pedal sections usually have several 16 ft stops of different characters to suit different situations, don’t let this mislead you into thinking that organ Pedal parts sound an octave lower than normal. Pedal combinations should always include 8 ft stops, and often higher ones too. Another thing is that the Pedal division is routinely coupled to whatever manual is being played, so that the bass part now includes many more high pitches than the 16 ft. The overall impression to the ear is that the bass part of the music is in its usual area, reinforced by sub-octaves (and even sub-sub-octaves if the organs possesses a 32 ft stop).
 
16 ft stops can often be found on the manuals, too, probably only one per manual, and comparatively quiet at that. They need only be used when there are plenty of higher ones drawn.

Plenum

It is a well-known acoustical fact that two notes at the same pitch are not as loud as two notes an octave apart, also organists soon found that drawing an 8 ft diapason together with an 8 ft flute produced a muddy sound which did not carry well. So, with a “rule” (not too hard-and fast) not to mix diapasons and flutes, the “plenum” effect is the drawing of all the stops of one family, usually diapasons.  In other words we get a stronger effect, not by having several 8 ft stops, but by adding the higher pitches to reinforce the basic 8 ft. A useful arrangement would be to have the Diapason Plenum : (16 ft +) 8 ft + 4ft + 22/3 ft + 2 ft + Mixture(s). This gives a combination with great clarity and carrying power. So plenum is not the same as full.  “Full Great” is either all Great stops (undesirable) or (better) the diapason plenum plus reeds 16 ft + 8 ft + 4 ft.

Other combinations

 

Photo by T.Dwyer

Provided that 8 ft predominates, any combination of the appropriate upper pitches can be used, e.g. 8 + 4 or 8 + 2 or 8 + 4 + mix or even 8 + mix.  These all give unique effects.

 

Study this photograph of the Great stops on a typical English organ. If you read the right-hand side upwards you will see the stops comprising the Diapason Plenum, or Diapason Chorus as it is often called. (Ignore the bottom stop which is a coupler, and the top stop which is a reed.)

 Now for the GPO organ

I have to say that the assortment we are given is far from ideal. There are several fullish combinations which sound alike, a mixture stop which is useless on its own, a diapason which is an octave too high, and two pedal combinations pitched an octave too high. Fortunately we can salvage a great deal, if you are prepared to do 15 minutes work.
 
Let’s look at the meanings first. Here is the GPO list as it stands, in a revised order, with fuller explanations in  common English terminology:

 

Prinzipal  Diapason 4 ft (often called Principal with a c)
Scharf  IV Mixture of 4 ranks (high 8ves and 5ths)
Flutes   Flute stops at 8 ft and 4 ft combined
Cornet Cornet (a solo stop sounding vaguely like a trumpet)
Haupt Mix Great Diapason plenum ( 8 + 4 + 22/3 + 2 + mixture)
Hauptwerk all stops Ditto plus reeds 16 + 8
Brustwerk all stops  Full Choir, like Haupt mix, brighter
* Baroque Plenum Very similar to Haupt mix
* Baroque Plenum Reeds Virtually identical to Hauptwerk all stops
Baroque Plenum Ped Pedal stops 16 + 8. One is a reed, lacking the top five notes.
Baroque Plen Reed Ped Ditto plus more reeds and a 4 ft.
Full Organ  Full Great and Choir coupled together
* Symphonic Plenum Full Great and Choir coupled together


We can happily discard those marked * above.  What we lack, apart from the Flutes and maybe Cornet, is the possibility of quieter combinations. Before you hit on the idea of using the Mod wheel to simulate a swell box, I agree there is nothing wrong with that idea, except for one thing: a plenum inside a closed swellbox still sounds full, suppressed.  If you put a brass band in a room and shut the door, when they play forte it doesn’t sound like a brass quartet!  Fortunately, there’s a way to get proper quiet stops; that’s where your 15 minutes work comes in.

Setting it up in a Sequencer

N. B. If you are a Sonar 3 or 4 user, I have already set up a template which will save you the bother of the work outlined below.  Download it from here
 
You will need two instances of the Kontakt player. In the first, load up the eight slots as follows:
Prinzipal, Prinzipal, Prinzipal, Prinzipal, Scharf IV, Flutes, Flutes, Cornet.  Tune the first Prinzipal down an octave so that it shows –12.00 ST. (This is because the given Prinzipal is a 4 ft stop, and in any case lacks the bottom octave we require.)  Leave the remaining stops alone.
 
In the second Kontakt player load the first seven slots with Brustwerk All stops, Haupt Mix, Hauptwerk All Stops, Full Organ, Flutes, Baroque Plenum Pedal, Baroque Plen Reed Pedal. Tune the Flutes down an octave.
 
Now set up a MIDI track in your sequencer and insert a Mod Wheel cc#1 value of 127 at the beginning.  Clone this track 13 more times. Next allocate the stops to the tracks in your sequencer, in the order given, labelling them and tweaking them according to the following table:

 

Kontakt Player
& Channel No.
 Track Label   
Transposition 
Volume
(max 127)
1/1
 Diapason 8 
44
1/2
 Octave 4
34
1/3
 Twelfth
+7 
34
1/4
 Fifteenth 2
+12
34
1/5
 Mixture 
31
1/6
 Flutes 8 + 4  
40
1/7
 Flutes 4 + 2
+12
34
1/8
 Cornet
44
2/1
 Full Choir
50
2/2
 Great to Mix                 
54
2/3
 Full Great               
64
2/4
 Full Organ
70
2/5
 Ped Bourdon 16 + 8
40
2/6
 Ped Strong 16 + 8 
-12
50
2/7
 Ped Full with reeds
-12
60


We have now got ourselves a fairly useful organ.  Save everything: the two Kontakt multis as Organ 1 and Organ 2, and the sequencer piece as Organ Template. Now by starting with your template you can make either an organ solo, or a piece for orchestra and organ by adding the necessary instruments.  Try out each sound now with your keyboard. You may need to adjust my suggested volumes, remembering that single stops must be distinctly quieter than combinations.

 Back to top

Using the New Organ

Here are some suggested uses of this organ.  We get combined stops by layering our music (copying to other tracks) – this will be done almost entirely with Organ 1. N.B. If volumes need changing temporarily, do it with Mod Wheel.  The overall volumes (cc#7) are there to preserve the relative strengths of the stops.
 
Manuals:
  • Flutes 8 + 4 on their own.
  • Flutes 8 + 4 with Flutes 4 + 2 for a slightly louder effect. You can even add the Mixture for a mf result.
  • Cornet solo on one manual, accompanied by Flutes 8 + 4 on another.
  • Diapason 8 on its own.
  • Diapason 8 solo, accompanied by Flutes 8 + 4 on a separate manual.
  • Diapason 8 plus any combination of Octave, Fifteenth and Mixture, for range mf – f.  Only use the Twelfth if the Fifteenth is also present.  [N.B. Set up all five of these and compare with Great to mix (Kontakt 2/2) and they should be at about the same volume.]
  • Flutes 8 + 4 plus Fifteenth and/or Mixture
  • The other, fuller manual tracks of Organ 2 according to taste. 
Pedals:
  • Bourdon 16 + 8 for p or mf effect
  • Ped Strong for forte (use when manuals are using Full Great or Full Choir)
  • Ped Full for fortissimo (use when manuals are using Full Organ) 
* You could even combine some of these pedals for extra strength.

Manuals and Pedals

You don’t have to use pedals all the time– they give a weighty effect, so they are often omitted for lighter passages, but they are used more often than not. You either couple them to the manual being used, or you don’t. Personally I recommend that you usually do. In the sequencer we must ensure that the bass part appears in the pedals and also in the manual, so the manual has all the upper parts plus the bass. (It is probably convenient to have a separate track for the manual’s bass line.) It is beginning to look a little complicated, now, perhaps; but it soon comes out easily once you try a piece.
 
You do not have to use 16 ft on the pedals, you could happily place the Diapason 8ft on the pedal part, and the manuals could have Flutes 8 + 4 in the left hand, and Cornet or Diapason 8 ft in the right. (No coupling of the pedals to manuals, as in a Bach Trio-Sonata.)


Swell effect

As things stand, none of the GPO organ manuals is enclosed, and so are at a constant volume level. Most organs have at least one manual enclosed in a swellbox controlled by a large tilting pedal, so we might as well avail ourselves of this facility.  Using the Mod Wheel can easily simulate this effect, but remember that you will always be lowering the volume which we have set at full. So a crescendo must be done as an organist would do it: lower the volume before sounding the notes, then bring up the volume gradually. (Don’t begin in near-silence, that’s unrealistic: a closed swellbox will give about ¼ to 1/3 of the open sound,) Of course we can do a diminuendo by the opposite process.  I recommend that you apply the swell to the Full Choir rather than the Great which is nearly always unenclosed. You can always get the crescendo effect used by organists by adding a stop at a time, at suitable rests. This also applies to the pedals; they are never enclosed except on the very largest organs.

Placing the organ in the sound-stage

Organ with orchestra will usually involve a concert hall. In that case the organ will be central, at the back of the platform behind the percussion. Work out the correct reverb parameters; do NOT give church-type reverb to the organ.
 
If you really do want the organ in a church, either alone or with an orchestra, then church or cathedral acoustics will be appropriate. The main thing is to give the organ and orchestra the same acoustical environment.

 Back to top

Composing for the Organ

Organists will need few hints here. Non-organists take note: 

1)      Remember there is no sustaining pedal; the fingers must hold the chords.

2)      Sounds can be sustained indefinitely; the organ is not going to run out of breath.

3)      The two hands can play on the same manual or on two different ones.  The only limit to the speed and brilliance of the music is what normal hands can achieve, as on a piano. [Tip: since you cannot make an accent by velocity, use the organist’s device of making the previous note staccato.]

4)      Pedal parts must be practical. Fast scales are not possible, and in any case organists prefer to play with alternate feet rather than slide one foot about. It is easy to go from a natural to the next sharp or flat (or vice versa), by using heel and toe; and it is easy to move from one natural to the next; but as soon as we have three naturals in a row, there’s either an awkward hop with one foot, or preferably the first foot crosses behind the second. So a scale of C major would go L R L R etc. (not too fast).

Organs in Baroque times had shorter pedals than modern ones, and it was harder to cross the feet like that. Scale passages could be done in a slow fashion, but anything fast preferred using alternate feet and so produced a zig-zag motion.  Take a look at two fugue subjects in Bach’s organ music:

 

 Note the constant alternating foot movement. In the second example the right foot would have to jump at the bracketed places.

I am not saying you should get paranoid about this point, especially with our modern pedalboards: just try to visualise the organist’s feet while you compose. For example, if you give him a pedal trill on bottom C whilst he is playing at the top of the keyboard with his hands, he will likely fall over.  Have a look at this picture and you can probably see how the feet would have to manouevre:

 

Photo by T.Dwyer

 Notice also the two expression pedals controlling the shutters on the two enclosed manuals (Swell and Choir). 


Another useful device is the holding of a long note in the pedals (Tonic or Dominant) whilst the manuals play several bars of active music. Harmony theorists have named such a note a “pedal” even in non-organ music.

 

5)      Finally, remember that organ music should have a measure of dignity. It can be showy, even flashy at times, but never cheap. And forget tremulant/vibrato, or whatever. Make your listeners awestruck!

Postscript: Extra stops now available with the new GPO Updates (after Oct. 20, 2004)

1) Load Prinzipal, tune down 12 ST to be an octave lower, set Freq Vol to full, leave rest alone. You now have an 8 ft Flute which can be used as manual or pedal.
2) In the next slot, do exactly the same except that you don't tune down an octave. This is a 4 ft Flute.
3) One more time, this time tuning an octave higher, you have a 2 ft Flute.

Unlike the given Flutes 8 + 4 which are locked together, you may now play the above three in various combinations: 8 alone, 8 + 4, 8 + 2, 8 + 4 + 2. This confines your combos to the flute family, but there is no reason you shouldn't mix them with the Diapasons, if you avoid doubling at the same pitch, so you could have, for example: Flute 8 + Flute 4 + mix, or Diap 8 + Flute 4 + Flute 2, and so on.
4) Load up the Cornet and again turn Freq Vol to full. This now resembles a Quintaton, or a rather strange Oboe. Best used for quiet solo.


 Terry Dwyer
 October 2004

 back to top
Garritan Orchestral Libraries, Box 400, Orcas Island, WA 98280 USA..... Telephone: 360-376-5766 .....Email:
Copyright © 2004. All rights reserved.