The Organ

by Martin Wheeley mmii

Other than the building itself, what is the most valuable material item most Churches possess? A gold or silver chalice perhaps? A painting or sculpture maybe? Possibly an ancient book? In fact, it is probably the organ. In a Church I used to know many years ago in Brixton, the rather fine 3 manual organ was insured for more than the Church Hall.

A Church organ is a complex and precision piece of engineering. My personal love of organ music is based in equal parts on appreciation of the craftsmanship of the organ builder, the genius of the composer and the musicianship of the organist.

It is interesting to reflect that in the nineteenth century, the loudest sound most people had heard was thunder and the second loudest was a church organ. A few would also have heard gunfire, which generally comes somewhere between the two.

An organ makes its sound by blowing air through pipes, in fact, reduced to the basics, an organ is a collection of whistles, albeit highly refined whistles made by craftsmen. The tone is governed by the shape of the pipes, the material they are made of (various types of metal or wood) and the craftsmanship of the builder who "voices" them. Voicing means makes small adjustments to the pipes until they sound appropriate for the building and blend properly with each other. Each stop knob at the console connects a rank of similar-sounding pipes (one for each note on the keyboard) so that when the player plays a note on the keyboard or manual, air from the wind chest is admitted to the pipe corresponding to that note. The player can draw more than one stop at a time, so that playing a note makes several pipes sound ("speak"). A single rank of pipes may have a distinct and delightful tone of its own but the glorious and varied sounds of an organ are built up by using different combinations of stops. The combination of stops in use at any time is known as the registration.

In small organs, the mechanism connecting the keyboards to the pipes consists of levers and wires, called trackers. The craftsmanship involved in making those components, so that they work perfectly, every time, without sticking and so that the player does not have to put an immense force on the keys to play them, is one of the high achievements of the organ-builder’s art. Historically all the levers and bearings were made of wood and wire. This limited the size of organ which could be built with tracker action, because of the weight and unavoidable friction between the components. Later on, pneumatic action was invented, in which air entering small bellows gave some power assistance to the force exerted by the player, and so enabling a larger instrument to be played. The disadvantage was that the air took time to move and there was a noticeable delay between pressing a key and the pipes speaking. The player therefore had to have his fingers a beat or so ahead of what was actually sounding from the pipes. It takes a very competent musician mentally to detach what the fingers are doing from what he or she is hearing. It also means that any small mistake is not apparent for a moment or two and by then may have turned into a much larger mistake. Later still came electric action, which responds much more quickly. Nowadays, builders are reverting to trackers: the necessary parts can be precision-molded in lightweight plastics. The new organ in the Symphony Hall in Birmingham has about 80 stops and the main console is tracker action. Many organists and organ purists consider tracker action to be superior, because it keeps the player in direct contact with the pipes.

There are two main families of organ pipes, the flues and the reeds. The flues are, as their name suggests, just plain chimney-like pipes. Flues may be open or stopped. In open pipes, the upper end (usually, although some pipes may be installed horizontally to make best use of the available space) is open to the air. Stopped pipes have a cap (in fact, a tuning slide) over the end. The reeds operate on a quite different principle, by the vibration of a metallic reed, with a pipe above it to resonate and amplify the sound.

The flues come in three sub-families:

• The diapasons, which are the fundamental tone of the organ, when it is just being an organ and not trying to imitate anything else. The pipes which form the display for the organ case are generally Open Diapasons.
• The flutes. As the name suggests, they have a softer flute-like tone and are usually made of wood, which adds to the softness of the sound. Flutes are also generally stopped pipes and the stop called Stopped Diapason is in fact a flute, despite its name.
• The strings. These are generally diapason-like in construction but are rather narrow in proportion to their length. The sound has a definite violin or cello-like stringy quality, although nobody would ever confuse it with those instruments.

The reeds are frequently intended to imitate various orchestral instruments: trumpet, oboe, tuba and the like. The imitation is less than perfect but is recognisable. The sound is certainly very different from the flues. Reed stops are even more expensive to make than flues and are often not present on small instruments.

Early organ builders sought ways to make their instruments louder, so that the sound could fill a large building. Making larger diameters pipes or blowing them harder were two answers but had the disadvantage that it altered the tone, not always for the better. It also needed much more wind to make the pipe sound properly, which was a significant problem when a man or men operating large bellows supplied the wind. Another solution was to use several stops at a time and so add more pipes sounding together. This was good up to a point but this eventually resulted in a "muddy" texture to the sound, which was not always attractive to the ear. The genius of these early builders was to realise that by adding pipes sounding an octave higher than the note played added both to the loudness and the brilliance of the sound. Subsequently they found that adding pipes sounding two, or sometimes three, octaves higher made for even greater volume and brilliance.

To let the organist know what pitch of note he or she can expect from a stop, there is a number engraved on the knob next to the name of the stop. The number is approximately the length in feet of an open pipe corresponding to the lowest note on the keyboard (two octaves below middle-C). Please do not tell anyone in Brussels: all organs world-wide express their pipe-lengths in feet – no metrication here! Normal pitch is 8 ft, an octave higher is 4 ft and two octaves higher is 2 ft. There are of course exceptions: stopped pipes sound an octave lower than would be expected from their length. The longest pipe of a Stopped Diapason marked 8 ft and sounding at that pitch would actually be only 4 ft long. There are also stops such as the harmonic flute, which have a hole half way along each pipe: for those, an 8 ft rank would sound at 4 ft pitch.

On the pedals, which always sound an octave lower than they appear, the normal pitch is 16 ft. Some large organs may have a 32 ft pedal stop, sounding an octave lower still and very rarely there is a 64 ft stop, another octave lower. The lowest notes on 32 and 64 ft stops are lower than a human ear can hear but they can be sensed through the skin, generally as a warm-feeling vibration in the air and even parts of the building. The music master at my school was an accomplished organist and when playing for our beginning and end of term Services in Chester Cathedral, usually managed to find an excuse to use the low registers of the 32 ft pedal stop.

Later still, pipes were added that sound a musical interval other than an octave above the note played. Because these stops change the note, they are called mutations. A common mutation sounds a twelfth above the note played, that is, if the note played is middle-C, the note which plays is the G one and a half octaves higher. This stop, which is a small diapason and is called the Twelfth or Nazard, sounds rather odd when used with other quiet stops but when added to a chorus of moderately (or very) loud stops, adds greatly to the richness of the sound. The pitch shown on the stop knob is 2 2/3 ft. The Seventeenth or Tierce (1 3/5 ft) and Nineteenth or Larigot (1 1/3 ft) mutations are often found on larger organs.

A variation on the theme of mutations is the mixture or combination stop. A mixture consists of several mutation pipes all controlled by one stop knob and sounding together. Mixtures of two to five ranks are usual. The pipes, all small diapasons, sound at various musical intervals above the note played, for example, 19th, 22nd, 26th, 29th. The intervals vary according to the builder’s intentions and can alter the character of the sound of the other stops. For example, a mixture called the Cornet, added to a diapason, makes a reedy sound reminiscent of the brass instrument of that name.

The description of mutations and mixtures may all look a bit peculiar in print but you may be certain that when even a moderate-sized organ is giving a rich sound, there will be mutations and mixtures contributing to that glorious tone.

A large Cathedral or Concert organ may contain five thousand pipes or more. Of those, no two are exactly the same size or shape. This of course does not allow very much in the way of automated or machine production and there is a great deal of skilled handcraftsmanship – and consequently cost – in building organ pipes. Each one has to be tuned by hand, so that is rather a long job as well.

The Manuals or Keyboards

Even quite small organs have two keyboards or manuals. Indeed, they are often referred to as separate organs, as indeed they are. By being placed close together they may be played together or separately, to get whatever variations in sound the organist wants. However delightful the sound of any individual stop or combination of stops may be, to listen to it for a long period can get rather tedious. It is the artistry of the organist to make changes in the sound to give expression and interpretation to the music. Rapid changes of tone can be made by moving from one manual to another, with an appropriate registration already set on it. A further possibility is to play different musical parts in contrasting tones on different manuals. One example is the well-known Trumpet Voluntary by Jeremiah Clarke: the trumpet theme is played on a reed stop on one manual, with the accompaniment of diapasons and flutes on another.

A standard organ manual has five octaves, 61 notes, starting at the C two octaves below middle-C. To save cost, smaller organs may have 54 or 56 notes – the last few at the top are very rarely used.

In a two manual instrument, the lower manual is called the Great, or Great Organ. It contains the principal stops of the organ and forms the foundation to which other subtleties may be added.

Organ pipes are either sounding at their full volume or silent, there are no in-betweens. Therefore to play loudly, the organist must draw one or more loud stops and to play quietly, must draw a smaller number of stops or quiet stops. The only other way to vary the volume of sound is to enclose the pipes in a wooden box, one side of which consists of slats like a large wooden Venetian blind. The slats can be opened or closed by the player, using a foot pedal, to increase or decrease the volume. The tone alters slightly at the same time – like closing the door when loud music is being played in the next room. The manual above the Great, whose pipes are in the enclosed box is called the Swell (or Swell Organ).

Other manuals in larger instruments, in order of addition are:

The Choir, below the Great. The Choir Organ is often enclosed in a second swell box (it is still called a swell box, even if the pipes it contains belong to another manual) and has stops designed for accompanying choral music, used in addition or in contrast to resources available elsewhere in the organ. In some instruments, this third manual may be called the Positive Organ, especially if placed in a separate case behind and below the organist’s bench on an organ screen.

The Solo, above the Swell. The Solo contains the organ equivalent of "heavy metal", powerful and distinctive stops, which may be imitative of orchestral instruments – trumpets, oboes, concert flutes or string tones. The Solo Organ may also be enclosed in a swell box.

The Echo, above the Solo. Five manual instruments are rare. If present, the pipes for this manual may be placed in a high or remote part of the building, to provide an effect of a distant echo.

Very very few organs have more than five manuals. If there are more, there are design problems to let the player actually reach the keys. The sixth and seventh (no organ has more than seven – unless you know differently) manuals have various names, depending on the creativity of the designer and builder.

The pedals are another keyboard played by the organist’s feet. There are usually about 2½ octaves (32 notes) of long wooden keys, laid out like a very large keyboard. The lowest note on the pedal board corresponds to the lowest note on the manuals but sounds an octave lower than the manuals because 16 ft pitch is the norm. The pedals are used to provide the bass harmony to many pieces but are also capable of playing the theme or melody. In a fugue, for example, the pedal part is the same as the fugue subject (main tune of theme) intertwining on the manuals. There are also many pieces of music which feature a prominent pedal passage and which would be incomplete without it.

Now, how does an organist with only two hands and feet get full advantage of all those manuals? One answer is accessories called couplers. These enable one manual to be coupled to another, so that notes played on the first also sound on the second. The pedals can also be coupled to the manuals but only extremely rarely vice versa. Couplers are controlled with stop knobs and have names like Swell to Great, Great to Pedal, or whatever.

Organs may also have various other accessories. Managing large changes in stops can be time-consuming and interrupt the flow of the music. To assist, there may be iron levers operated by the feet to give certain preset combinations of stops. A development of those is combination "pistons" (so-called from the days of pneumatic action, when that’s exactly what they were) beneath each manual, to be pressed by the thumbs, which also give preset registrations. There may also be toe pistons performing a similar function. In some organs, the stops selected by the pistons can be altered; organists refer to the process as "changing their combinations".

To summarise, even a small organ is a complex, precision and expensive machine. The organist must not only be able to keep the music going with both hands and feet, but also manage the stops, accessories and swell pedals to get the huge range of expression which only the organ, the King of Instruments as Mozart so aptly called it, is capable of.

What of the future?

Electronic organs have been around for many years and were rather variable in quality (meaning many of them were not very good). The modern electronic organ is a dedicated computer and imitates the sound of the real thing so closely that even professional musicians have difficulty telling the difference. In fact, the sound of an electronic "pipe" may be synthesised to be exactly like the sound of equivalent high quality pipes, by recording from the best pipe organs around. In some cases, it is the slight noise caused by the mechanical parts during registration changes that identifies the real thing, rather than the musical sounds.

The craft of the pipe organ builder will remain for hopefully many years to come but will become rarer and more expensive. Computers and programmers will however become more yet more widespread, better still and cheaper. The difference in cost will be the deciding factor in many places where an organ installation is being considered: a very good quality electronic organ may costs less than a quarter as much as an equivalent pipe instrument.

The Organ at Breedon

The organ at Breedon is a very modest instrument, although to replace it would cost the equivalent of a moderate-sized new car. It has no maker’s name on it, although the place where a small plaque used to be is still visible above the stops.

It has a total of 410 pipes and as mentioned before, they are all different. There are only nine speaking stops, plus 4 accessory stops. The action is tracker, except for the pedals. The tracker mechanism was not working properly and was replaced with electric action some years ago. The specification is shown below:

Two manuals each with 56 keys but the top two notes have no pipes, so only 54 notes are actually available – another cost-saving. 30 note pedals.

* Only goes down to Tenor C, i.e., the bottom octave is missing, for cost-saving.

† Not a completely separate stop. It has a top octave of its own but "borrows" the rest from the Bourdon. This is known as an extension and is another cost-saving measure.

All the stops are flues, there are no reeds.

The only String is the Viol d'Orchestre, which has a pleasant tone but is rather quiet.

Our entry in the National Pipe Organ Register is here.

FAQ: Can I have a go?

If you are an organist, you would be most welcome to accompany Services. If anyone who has reached grade 5 or more on the piano would like to play, I shall be glad to show them the Breedon instrument and try to encourage them to take organ lessons.