CONTINUO ORGAN II: Transposing the Continuo Organ
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|Transposing the keyboard of the Klop continuo organ|
Transposing the continuo organ…
As the Klop design has been refined over many years, there may be minor differences in the transposition facility depending on the age of the organ. The earlier instruments may only offer the common A415/A440 pitches. Later instruments typically add A466 as standard, while others might also include A392 to offer fully four positions of the keyboard: A392/A415/A440/A466. For these newer instruments, pipes are available to cover the 54-note C–f''' keyboard compass at the A440 position. When transposed, the available range may slightly decrease to give the effective compass shown in the table opposite.
|Effect of Transposition|
The bass and treble of each rank can be drawn separately. This split occurs at middle c' at the A440 position, and if there is a treble-only Quint rank, this is its lowest note. It follows that when the keyboard is transposed, the location of the split moves. This is shown in right column of the table.
The physical process of transposition is shown in the movie below with its attached technical description. The keyend blocks of earlier models may have turned brass locating pins, both of which must be lifted at the same time to allow the keyboard to be unlocked and slid to its new position. More recent instruments—like the example—have concealed locating pins which will vacate their holes when the keyboard is slightly lifted at both ends.
|ALWAYS ASCERTAIN THE KEYBOARD POSITION PRIOR TO TUNING
SO THAT YOU ARE TUNING THE INSTRUMENT AT ITS CORRECT PITCH.
Of course, if the organ was last tuned in an unequal temperament, it will require retuning after transposition because the keys will have been transposed along with the pitch.
|Klop Continuo Organ — transposition
Carey Beebe demonstrating how to transpose the Klop Continuo Organ A392/A415/A440/A466.
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