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Reed Organ 2

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The combination of Free Reeds with Variable-Pressure Bellows formulated the essential of Harmonium or Orgue-Expressif. And the idea of stops the rank of which is divided in two sections (treble and bass) on single manual keyboard, influenced by Italian Organs, seems contribute to make this instrument compact and to let the player concentrate on the "expression" with its simplicity.

After the formula of "Harmonium" registered by Alexandre-Francois Debain in 1842, this new organ has 4 ranks of reeds in three different pitches, i.e. one 16' considered as a foundation rank; two 8' as a foundation and a reed rank; one 4' as a reed rank. Each rank is divided in two between E3 (e') and F3 (f') so as one can manipulate them independently.

Playing Bass 4' (reed rank) in left hand and Treble 16' in right hand produces the contrast of tone color in the same pitch, that is, the C2 (c) key in 4' one hand sounds c' (C3 in 8') brilliantly and the C4 (c'') key in Treble 16' (foundation rank) on the other hand sounds also c' but softly. This is the way Harmonium has obtained the double-keyboard effect even with single keyboard structure. Later this effect is to sophisticate with the invention of the "Double Expression by Victor Mustel in 1855 which was inspired by Barker lever".

Abandonment of the resonator thanks to the generous harmonic structure of its sound produced by free reeds made Harmonium much more compact than traditional pipe organ however, this caused a new problem to resolve : bass notes dominate over
treble ! Generally speaking, the sound volume (energy) depends on the superficies of the tongue of a reed. And there is always a good proportion length-width of tongue.
In consequence, a Bass (long and wide) reed sounds stronger than Treble (short and narrow) one. Without resonater it's very difficult to correct this unnatural sound balance. Many builders tried to ameliorate this inconvenience : Sourdine by Alexandre, above-mentioned Double-Expression by Mustel, etc.

In the next page (publication in December 1998) I'll explain some aspects of Reed Organ Music in the second half of the 19th century.

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Image of this page :
Agati Organ (1843) of St-Michel church, Sospel (F-06380)
photo taken and retouched by
(C) 1994 Shoichiro TOYAMA
Last modified : 07/12/1999
Maintained by Shoichiro TOYAMA Mr.
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