If we were able to look inside the organ we would soon readily appreciate what craftsmanship and traditions of centuries are embodied in the king of instruments. Whereas the principles of organ building have not changed since before the days of Bach, great advances have been made in the mechanism, enabling the organist to perform with comfort, music which on older organ would have required much physical effort.
Tone is produced by the simple principle of wind being blown through a pipe, and there are over 1500 of them, ranging from 16ft to ¾”. The pipes are arranged in rows: each has its own characteristic sound, and contains a complete set of pipes corresponding to the notes on the keyboard i.e. 61 pipes per sound, such a row of pipes is called a stop. Stops may be roughly divided into four families: Diapasons, Flutes, Strings and Reeds. The Diapasons give that broad rich tone which is the chief characteristic of the organ. Flutes and Strings more or less correspond to their respective instruments in an orchestra. Reed pipes contain an actual reed which is made to vibrate inside the pipe on the same principle as the oboe and clarinet.
A stop of which the notes are of normal pitch (as on a piano) is known as an eight foot stop, the longest pipe being eight foot in length. A four foot stops sounds an octave higher, a sixteen foot stop and octave lower, and so on.
On the console there are three key-boards or manuals, a row of 43 ivory stop keys along the top, and a set of thumb pistons underneath each manual. Theses pistons are duplicated in front of the pedals. By means of the pistons the organist can draw a pre-selected combinations at an instant without moving his hand away from the keyboards. The selector switches (135of them) are in drawers at either side of the console.
The three manuals and pedals each control their own department of the organ. Generally speaking, the deepest sounding pipes are played by the pedals. The middle manuals operates the great organ, i.e. the main body of the organ: above is the swell, all the pipes of which are enclosed in a box with venetian shutters, which can be opened and closed by means of one of the balanced pedals situated over the pedal board. The lowest manual is the choir, because its stops are quiet ones suitable for accompaniment. The Tromba stop is playable from the great or the choir manual, and is of heavy wind pressure (6 inch as against 31/2 inch). The choir organ is also enclosed in swell box, which is controlled by the other balanced pedal.
Wind is provided by a 3HP ‘Discus’ two stage rotary fan installation which is also fitted with a generator unit for organ action current supply.
Complex and bewildering as an organ is at first sight, its devices once mastered enable the organist to contribute immeasurably to the praise and glory of God.
So now you understand the considerable complexities of the ‘King of Instruments’ why not sit and listen to Tim’s splendid pre and after service voluntaries, during the past months we have had pieces by Guilmant, Parry. Bach, Thalden Ball, Merkel, Boellmann, Widor and Karg Elert. I feel sure that in the future we shall be treated to many more accomplished renditions of organ works by famous composers. So arrive a bit earlier and stay a bit longer, you will not be disappointed.
Organ details from an article written in 1957and updated
Neville Holt, February 2008.
Tell
A Friend
Bookmark
Print
Page
Site Map
