The organ tour

The Organ Tour

Before you start

Things to look out for

The Map

The map shows a cross section of the organ and will help you keep your orientation as we navigate our way around. Look out for the coloured spots so you can pinpoint what it is you are looking at.
It is hidden at first but pops out from beside the slide heading; just roll your mouse over it. Not all slides have this feature.

Hot Spots

These are points on the photograph where you can gather information quickly. Click on the different colours to better understand what you are looking at.
Note, some may have sound — so turn it up!

An Amazing Machine »

An Amazing Machine

The organ is first and foremost a musical instrument but is also a complex feat of engineering and a great work of art with a history of 2,500 years.

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Wind

There is enough air pressure stored in the bellows to push an elephant 200m!

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Deep in the basement three electrically powered rotary blowers with a total capacity of 209 cubic metres of wind per minute, provide wind at 3 basic pressures – low, medium and high. Large tubes convey the wind up to the organ, 10 metres above, where it enters the reservoirs.

Reservoirs


The three basic wind pressures from the blowers are further subdivided into 23 reservoirs or bellows where pressures are stabilised for all conditions of demand, whether it's just one pipe sounding or hundreds. Different parts of the organ operate on different wind pressures – quiet sounds on low pressures and the loudest trumpet pipes on the highest.


Windchests


The wind is conveyed to numerous windchests on the organ’s three levels. These contain the mechanisms that let air into the pipes at the organist’s command. The organ’s 5,291 pipes stand in rows on the windchests.


One of the huge blowers in the basement Some of the 23 reservoirs Windchests and pipes

« The Organ Tour

Many Organs in One »

Many Organs in one

A large organ is several organs in one, each with its own keyboard.

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Choir organ
Great organ
Swell
Solo and Bombard Organs
Swell Box Controls
Pedal Organ

The organ is really a collection of organs each with its distinctive character. In New Zealand instruments usually have two or three keyboards – only a few, like the Town Hall Organ, have four. The lowest keyboard controls the Choir Organ which controls soft accompanying sounds. The Great Organ (second keyboard up) has the big bold sounds while above it, the Swell Organ has a variety of sounds with its pipes enclosed in a swell box. The fourth keyboard controls the Solo and Bombard organs. The range of the keyboards is five octaves (61 notes). The different organs can be coupled together in a variety of ways – for example, they can all be played from the Great Organ keyboard.

PedalBoard

The pedalboard is a concave and radiating set of 32 large wooden keys arranged in sharps and flats just like the keyboards for hands, but with much wider spacing for the feet. It controls the Pedal Organ. In small instruments it will have only a few pipes but in large organs it’s expected to be as comprehensive as the keyboards since it has to play melodies as well as provide bass notes. Each keyboard can also be coupled to the pedals.

« Wind

The Console »

The Console

The flight deck of the organ.

The Music Desk

Pistons

General Cancel

Pistons

Swell Pedals

Pedal Board

Sequencer/Computer

Couplers

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Usually placed at the centre of the organ's façade, the console contains all the keyboards, the pedal board, the stop knobs and other devices that allow the organist to control the instrument.

The various divisions can be combined in many ways by the use of the couplers. For example, all the divisions (except the pedal organ) can be coupled to and played from the Great Organ keyboard. Computer technologies are used to facilitate stop and coupler selection.

« Many Organs in one

Stops and Keys »

Stops and Keys

Stops and keys determine which pipes are to speak and which are to remain silent.

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Stops are ranks of pipes of the same tone. Generally, there are as many pipes to a stop as there are keys on a keyboard. Stops are activated by drawing the stop knobs on the organ console, arranged at either side of the keyboards. A stop's name indicates the type of sound its pipes will make, as well as the pitch.


Stop names give a sense of the organ's long and rich history. Organ builders over the centuries, from all over Europe, have given names to the stops they have invented. Thus, in most organs, one can trace its German, French, Italian, American and British origins. The stop names of this organ are shown in the Organ History section.

Stop knob is pulled Electric motors move the slider under the rank of pipes Pressing a key on the keyboard completes an electrical circuit, releasing the air to flow through the pipes.

« The Console

The Pipes »

The Pipes

The pipes stand in rows of on top of large chests of pressurised air, ready to speak when a key is pressed.

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Most organ pipes are made of wood (brown in diagram) or metals (silver). The metal used is usually an alloy of lead and tin, but zinc and copper can be used. The Town Hall Organ is unique in having a rank of 61 pipes made of glass: this is the Kōauau or Māori flute.

Pipes come in many shapes and sizes, but in only two basic types:

Flue pipes (1—14)

These are built on the same principle as a flute or recorder. They are the oldest type of organ pipe and are the kind seen at the front of the organ. The wind pressure, the height and width of the mouth, the diameter of the pipe relative to its length, its shape, whether or not it has a stopper in the top (pipes 9, 13 and 14), and the material from which it’s made all determine the tone they produce.

Reed Pipes (15—21)

Every reed stop has a vibrating metal reed at the bottom (the boot) of the pipe. The ‘beating’ of the reed is amplified or modified by the pipe extending from it. The type of reed tongue, the pipe shape, its length and other tone altering features all affect the kind of sound. Particularly important is the pressure of the wind pushed through the pipe. The Town Hall Organ has many reed stops and some are very loud due to the enormous wind pressure!

Every organ pipe is made by hand just like the instruments of the orchestra.

« Stops and Keys

Different Sounds »

Different Sounds

Among the ranks of pipes are many different tones. Organists learn to recognize the different sounds and how to blend them to form an infinite range of tone colours.

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Organ pipes come in two basic types – the flue or labial pipe which is like a whistle or flute, and the reed pipe which has a beating tongue at the bottom of its resonator like a clarinet. These then split into five main tone ‘families’.

Rest your cursor on the coloured spots to hear a short sample of each family of sounds as played on the Auckland organ. You may need to turn up the sound on your computer for best results.


Principal
or
Diapason
Diapason (or Principal) is the organ’s basic sound. Some of these pipes are often seen in the organ’s façade. They are usually made of metal – either an alloy of lead and tin or zinc.
Flute
Flutes come in many types and can be made of wood or metal.
Strings
String sounds come from very skinny pipes and the effect is enhanced by ranks of pipes which are tuned slightly out of tune so they beat with the in-tune pipes.
Reeds
The loudest pipes. Reed pipes are used to provide the fortissimo and loud solo brass effects.
Orchestral sounds
Orchestral Sounds is the fifth pipe family. These are reed pipes but the resonators above the reed have all manner of shapes to give the required effect.

« The Pipes

The Māori pipes »

The Māori pipes

The Klais organ is the only organ incorporating the sounds of traditional Māori instruments.

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Former City Organist, John Wells, was determined that an organ in Aotearoa New Zealand should reflect local culture so he investigated the possibility of having sounds of traditional Māori instruments in the organ. Since organ builders through the centuries have made their versions of many types of flute and trumpet, why not so for Māori instruments?

Richard Nunns, a specialist in these instruments recommended the kōauau (flute) and pūkāea (horn) as possibilities.

Orgelbau Klais took up the challenge enthusiastically and spent two years developing pipes that would make the right sound. For the Kōauau pipes, scientific glass was chosen supported by oak bases and, for the Pūkāea, wood was used for the lowest twenty four pipes with metal (lead and tin alloy) for the remaining pipes.

If the tonal challenge was one thing, creating a range of sixty one notes, the organ keyboard’s compass, was another. The original Māori instruments have a range of only five or six notes.

A special feature was the opportunity to create carvings on the lowest wooden pipes of the Pūkāea, so Ngāti Whātua asked carver Arekatera Maihi to carve traditional motifs.

The wooden pipes of the Pukaea are carved by Arekatera Maihi using traditional Maori motifs. Consultant Ian Bell shows carver Arekatera Maihi how the organ Pukaea will make its sound

« Different Sounds

Different Pitches »

Different Pitches

Pipe lengths in the Town Hall organ range from half an inch (1cm) to 32 feet (10 metres).

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Each pipe in a rank is a different length. The longer the pipe, the lower the pitch and the shorter it is, the higher the pitch. If a stop knob of an open pipe has 8 on it, its longest pipe (bottom note of the keyboard) is 8 feet long and its pitch is the same as corresponding notes on the piano: 4 is an octave higher, 2 an octave above that (about 8KHz, on the top note of the keyboard). 16 is an octave below 8, and 32 another octave below (bottom note is about 16Hz).

By adding one to the other, a sound pyramid is built up. There are also stops of pipes with pitches between these unison sounds. They’re mutations and mixtures and add a range of harmonics to give the organ its distinctive sound. The stops can be mixed up to provide an endless variety of effects.

« The Māori pipes

Soft and Loud »

Soft And Loud

Changing the volume and tone on the organ is not like playing a piano.

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The organ cannot be made to sound louder or softer by striking the keys harder or more gently like on a piano, or by putting down a loud or soft pedal. Instead, the organist controls the organ’s volume in two ways. Firstly by adding or subtracting stops and secondly by moving the swell pedals controlling the louvres of the 'swell boxes' which enclose three sections of the organ.

We have seen that pipes of different octaves (8 foot, 4 foot etc.) can be selected together to build a harmonic 'pyramid'. Sometimes a stop will include a fraction in its name such as 2 2/3. This indicates that a note between the octaves will sound so we hear a harmonic sound. Stops called Mixtures cause three or four or even five notes to sound at the same time. These are tiny pipes that add a high (up to 17KHz), bright sound to the texture of sound the organist builds. This pyramid of sound is created by harmonic corroboration. Therefore by playing just one note, many pipes can speak. With all fingers on the keyboards, and with the addition of pedal notes, the organist can make more than 100 pipes speak at once producing the volume of sound that only the organ can create.

Finally, many of the organ's pipes are contained in one of three swell boxes (swell, choir and solo) which have moveable louvres on one wall. The organist controls these with a large foot pedal: a very effective way of producing a smooth crescendo or diminuendo in the music.

Different pipe lengths give different pitches. The organist opens or closes the swell box by moving a pedal with his foot. Mechanical shutters help to control the soft and loud effects of the organ.

« Different Pitches

An organ to be seen »

An organ to be seen

The organ has been built to allow people to walk through it.

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Most organs are things of mystery, locked away in a church corner or a gallery with only a few pipes visible. Not many people have seen inside an organ. From time to time the Town Hall Organ Trust arranges tours through this enormous instrument.

Public Walkway

While all organs have access for maintenance, public access is rare. The Town Hall Organ is designed for guided tours with passageways at three levels connected via an elegant solid oak staircase.

Come and see the Organ

The Model Organ

As well as the organ in the Great Hall, Klais Orgelbau built a demonstration organ that now lives in the Town Hall foyer. This is a complete working pipe organ, with just 5 notes, 15 pipes and 3 stops. Come and have a play!

The solid oak staircase connects the three levels inside the organ.

The model organ sits in the foyer of the town hall — come and give it a go!

« Soft And Loud

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