Organ Open House
Christ Church Cathedral
Sunday, September 30, 2007
12:30 to 2:00 PM
It’s time to satisfy that deep-seated urge of many music lovers: Just how does the organ that produces such wondrous music on Sunday actually work?
Patrick Wedd will be in the choir loft of Christ Church Cathedral this Sunday, September 30, 12:30 to 2:00 pm, as part of the Festival Orgue et couleurs and les Journées de la culture throughout Quebec to answer our questions.
If you want to do a little homework in advance, check out A Young Person’s Guide to the Organ (actually for the not-so-young) or even Pipe Organs 101. You will find a more thoroughgoing presentation in James Cook’s Organ History which includes an extensive section, The Organ and How It Works.
There is a short article on Christ Church Cathedral’s own Karl Wilhelm organ in the University of Quebec organ website. Scroll down to Montreal (there are over 60 Montreal organs described) and click on Christ Church Cathedral. Or simply click here.
In fact here is some simplified information that might help you. Click on underlined words for a more detailed explanation.
The present Christ Church Cathedral organ was built by Karl Wilhelm (video) in 1980 and located in a gallery erected especially for it over the main entrance. (The only remaining evidence of the earlier organ is the celestial organ case on the wall high above the chancel.)
The Christ Church Cathedral organ is built in the style of 17th-century North German organs. The master organ builder of the time was Arp Snitger. On the left is Arp Snitger's organ of the Pankratiuskirche of Hamburg-Neuenfelde.
Like North German organs Christ Church Cathedral organ has a mechanical action or tracker action, the tracker being the rod which in the simplest situation connects the key to the pallet which controls the entry of air into the pipe. More complicated connections involve rollers and squares besides the tracker.
The argument for mechanical action is that the player can feel the opening of the pipe valves and can make different kinds of attacks and releases by pressing and releasing the key slowly or quickly.
The keys on the Christ Church Cathedral organ operate by suspended action. The key is pivoted at its farther end. In the simplest scenario, the tracker is attached to the middle of the key. When the key is depressed, the tracker is pulled down and opens the pallet to allow air into the pipe. When the finger is removed from the key, a spring on the pallet returns the key to its "off" position and keeps it "suspended" until it is depressed again.
The pipes of the Christ Church Cathedral, of which there are 2,778, are assembled into 63 ranks, rows of pipes of one tone colour, which are then activated by 42 stops which prevent or allow the passage of air to a rank of pipes.
The ranks are gathered into five divisions, groups of ranks, each division with its own air chest and played from its own keyboard.
The Christ Church Cathedral organ has three manual keyboards. The middle manual controls the principal division of the organ, the Hauptwerk. Its pipes are not enclosed but visible. It produces specifically organ tones and the loudest notes are played on the Hauptwerk. Hymn singing is generously supported by the Hauptwerk.
The upper manual controls the Swell. It is so called because the sound of its pipes can be made to swell and diminish. Its pipes are housed in a box with shutters. These shutters are like large Venetian blinds that are controlled by a pedal.
The lower manual controls the Rückpositiv, the function of which is to play antiphonal effects with the Hauptwerk and to add brightness.
The distribution of the Hauptwerk, the Rückpositiv (located behind the organist as he sits at the keydesk) and the divided pedal towers in the Christ Church Cathedral organ can be seen by these photos of North German organs. Run the mouse over the photos. Notice the narrow base below the Hauptwerk of the Christ Church Cathedral so typical of the North German organ.
The Echo division, by way of exception, does not have its own keyboard but is played on the Swell. It is used antiphonally and its stops are quiet. It has 30 notes.
The keyboards of the Christ Church Cathedral organ have 56 notes, from Low C to G above high C. The natural keys are covered with bone and the sharps are ebony.
The pedalboard has 30 notes, from low C to F above middle C. It is of standard, radiating, concave design. A pedal board is played with the toe and heel of both feet.
Coupling allows one keyboard to be played on another. On the Christ Church Cathedral organ the Swell and the Rückpositiv can be coupled to (played on) the Hauptwerk manual and the Hauptwerk, the Swell and the Rückpositiv can be coupled to (played on) the pedal.
The principal pipes are of 75% polished tin. The flute pipes are of hammered tin-lead alloy. The casework is crafted of solid white oak and the decorative scroll work (pipe shades) capping the pipes is hand-carved butternut wood.
Now, get your questions ready for Patrick. If we are lucky, he may even pipe a tune.