From the purring of a cat to the roaring of a lion
The Father Willis organ at Saint Mary Magdalene can be made to purr quietly like a contented cat. It can roar like a defiant lion, either in the distance or alarmingly close. Dark mystery, evocative of a foggy Exmoor, is also within its compass, or it can offer tremulous, plaintive, solo voices. There are brazenly triumphant trumpets and trombones, or a whisper so soft that you have to strain to hear it. The organ can make all of these sounds because it was designed to add colour and expressiveness to words: to characterise joy or sorrow, pride or humility, defiance or pleading. The accompaniment of the liturgy is its primary purpose, and it has fulfilled this obligation with distinction for many years.
To make an organ play, you pull out a stop, press a key, and an electric impulse from the key will travel along a wire to open a valve under a single pipe, to allow a column of air to blow through the pipe to create a sound. All of the pipes in the organ, nearly 2,000, stand over reservoirs of compressed air. If you play a chord of 4 notes, 4 pipes will sound: if you pull out 10 stops, and play a chord of 4 notes, 40 pipes will sound. It is possible to join the mechanism of the manuals together, and therefore, to allow all of the stops to be brought into play together.
In the opening bar of Widor’s famous Toccata, there are 74 notes. The music is loud, marked fff by Widor, and therefore you need to have a lot of stops drawn. If you have, say, 20 stops out, arithmetic will tell you that the organ has to perform 1,480 electrical and mechanical actions to play that single bar, which takes about 4 seconds. There are 78 bars of music in the piece, so even if you add no stops, there are well over 100,000 separate actions that the organ has to perform. This does not take account of the tune, played loudly by the feet, using other pipes, and the fact that towards the end, stops are usually added to create the climax of the piece. This 4-minute piece therefore involves the organ making about 150,000 actions.