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Celebrating the pipe organ, the King of Instruments

Mailbag: “Coming to Terms”

November 09, 2007

Dear Michael,

What are ventils, levers, Barker mechanism, and is there any relation to today’s swell shades?




As you can see, answers to your questions are easily available by a simple ‘google’ search of the term.

   Ventils | Barker levers | Swell boxes

Ventils control wind to specific sets of stops. The ‘Barker lever’ provides a pneumatic assist to a mechanical playing action in a large pipe organ.

Swell shades, today and always, are louvers in the front of the ‘swell box’, the chamber in which the pipes of the ‘Swell Division’ are contained. Control of those louvers is by an accelerator-like pedal, allowing the performer to open and close the louvers and, thus, allow more or less sound to escape the ‘swell box’, setting the relative loudness of that division and also creating musical crescendo or diminuendo.



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