Some base information about a pipe organ.
It is a wind instrument.
The pipes are divided in so called stops.
A stop is a group of pipes with for one keyboard (manual, manus is the Latin word for hand) for every key one or more pipes.
A manual has mostly a size of 4 octaves plus some extra keys. The lowest key is a c, 2 octaves below the central c, the highest key can be an c, d, e, f, or g (often depending on the period that the instrument was made).
The pedals are a keyboard for the feet (pedal, pes is the Latin word for foot) and have a size of 2 octaves with most of the time some extra keys (d and f are common highest keys for the pedals of a pipe organ). The pedals of the bigger organs have their own stops.
The lowest key of a pedal is 2 octave below central c (the same as the manuals).
You can combine the stops of one manual with pull-out buttons or other kind of switches.
You can combine the stops of several manuals with so called couplers. You press a key on one manual, and the same key of the other manual is pressed also (dependent of kind of the mechanism the pressure weight is higher).
In the same way you can couple the pedalboard to one or more manuals.
There are 2 ways of making all kind of sounds.
- The sound of the pipe (dependant of the form of the pipe and the way the sound is produced).
- Reinforcing certain overtones by one or more stops.
1. Sound of the pipes.
The pipes are divided in 2 main groups, flue pipes or labial pipes (working according to the principle of a recorder), and reed or lingual pipes (a vibrating brass strip makes the tone).
Th The flue pipes can be divided in
- flutes (with wide pipes),
- principals (praestants, prestants, in English "Open diapason"), less wide pipes, the “common” organ sound, mostly the pipes you see in the front of an organ, and
- string stops (with thin pipes).
2. 2. Changing sound by reinforcing overtones.
Stops has most of the time a length in feet behind their name. Of course, this has to do with the height of the tone. An 8 foot stop (8&rsquo😉 has the same height as for example a piano. 8’ is the length of the pipe the lowest key of a manual or pedalboard. A 4’ stop (the lowest pipe is 4') is an octave higher, a 2’ stop is 2 octaves higher, a 16’ stop is 1 octave lower, a 32’ is 2 octaves lower.
When the pipes of a stop are closed above (also called gedackt or gedeckt), they sound one octave lower. But they get the number of feet as they sound. So the lowest pipe of a 8’ foot gedackt stop has in fact a length of 4’ .
Beside this there are stops with more than one pipe for one key. They are all overtones of the 8’ stops (and some are just overtones of a 16' stop). A stop with for example a roman numeral V of 5f has 5 pipes for each key, a Mixture III-V (or 3f-5f) is a mixture stop, with 3 till five pipes for a key. The overtones are most of the time octaves and fifths (for example the stops with the name mixture and Cymbale), some have also a major third in it (Cornet, Scharf).
String stops: common stops are: Violon, Salicional, Gamba, Voix Céleste, Aeoline.
Principal stops: common stops are: Open Diapason (other names are Praestant or Prestant, Principal, in French Montre), Octave, Mixture, Scharf, Cymbal, (the last three has more than one pipes for each key).
Flute stops: common stops are: Hohlflöte, Gedackt (Stopped Diapason), Nasard (a fifth stop, 2 2/3&rsquo😉, Bourdon, Unda Maris, Nachthorn, Waldflöte, Rohrflöte (Chimney flute), Spitz flute (flute/String hybrid, same as Gemshorn), Sesquialtera (a flute mixture stop with 2 pipes for every key, a fifth and a major third, 2 2/3’ and 1 3/5’, a beautiful stop combined with a Flute 8' stop for melodies), Cornet (a Mixture stop), Subbas (just for pedal).
Reed or lingual stops: Trumpet, Trombone (Posaune), Oboe (Hautbois), Cromorne (Krummhorn), Bassoon (Fagotto), Dulcian, Vox Humana.
A plenum is a combination of 16’ (If present), 8’, 4’, 2’ plus one or more mixture stops, most of the time principal stops, can be combined with flute stops.
A plenum can also contain reed stops, that give even more power to the sound.
A tremolo is not a stop but the possibility that the wind flow flutters, so in the tone a kind of tremolo is heard, is used with soft stops mostly.
A swell box is a set of stops, mostly attached to one dedicated manual, often called Swell, that are placed in a box that can be closed and opened with a pedal (as a swell pedal with an electronic organ). In this way you can alter the dynamics of a tone.
The Manuals have names that come from the place where the pipes of that manual are placed.
Hauptwerk, Great. The German word Haupt (head) refers to the place where that pipes are, near the head of the organist.
Rückwerk, Positive. Indeed, the pipes are placed at the back of the organist, in the balustrade most often.
Brüstwerk (under the Hauptwerk)
Öberwerk (above the Hauptwerk)
In English other names are in use.
Combining stops. A good start to discover the sound of the stops is, just one 8' flute stop. Then combine it with a 4' flute and after that with a 2' (8+4'+2', but also 8'+2'). And if present, what does a 16' flute?
Then you can do the same with principals. 8', 4', 2', a mixture stop, 16' , 32' (the last only on the pedal).
Combining them with some flute stops.
And then with reed stops.
You can do this on several manuals.
Use 2 manuals, one with only 8' for accompaniment, and the other for the melody (a reed stop combined with a flute stop, 8' or 4', or the sesquialtera with a flute 8' stop). The bass notes can be played with a 16' flute stop, combined with a 8' flute stop.
Listen also to string stops and experience the difference in sound with principals and flutes.
You will see, that the samples of the Konzerthaus Organ contain not only the individual stops, but also combinations (plenum with and without reeds). After exploring the individual combinations you can also explore that samples.
And so on. I hope this helps a little. And... 😮 this has become a little long story. But at the end: the organ is called the King (or Queen) of all instruments, so it should be worth it.
AND in a way it is a predecessor of VSL. In the 16th and 17th century people were trying to make an instrument with all the other instruments in it (look to the names of the stops, Viole, Gamba, Flute, Trumpet, Clairon, Posaune). In the nineteenth century César Franck said: "Mon orgue, c'est mon orchestre."
And in this sense I have to say: VSL does a better job in combining all the instruments into one machine 😮😕😉
