The Reed Stops - Rodgers Columbian 75 Owner's Manual

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In the Pedal Organ, the Bourdon and Lieblich Gedeckt at 16' pitch
and the Flute at 8' pitch provide the soft to medium-heavy foundation
for ensemble playing. Flutes at 4' and 2' provide the basis for
lighter Pedal registrations.
THE STRINGS
The sound of a soft ensemble of bowed stringed instruments
is a favorite effect of all musicians. It was only natural,
therefore, that this sound should eventually find its way into
the organ. The RODGERS ORGAN provides the Gemshorn sound on
both the Swell and Great. This is a string-like hybrid tone
quality, having an incisive edge and harmonic development,
yet broad enough to make an ideal accompanimental texture.
On theJAMESTOWN ONLY there is an extra set of genera tors, playable
from both Great and Swell manuals that create the celeste effect.
An
organ Celeste is created by setting precisely tuned pitch
sources against purposely sharp-tuned ones. Historically,
the resulting beats attained by the two pitch sources "fighting"
each other are said to create heavenly voices, hence the name
Celeste.
The Gemshorn Celeste II is available on the Great where it
provides a warm full sound ideal for accompanying solo voices
on the Swell, and it also provides a subtle sound for use during
quiet moments of a church service. The Voix Celeste II on
the Swell is somewhat thinner and brighter than the Gemshorn
Celeste II, giving a celeste of a different quality, yet useful
to accompany the solo combinations on the Great. When coupled
together, the result is an extremely warm, rich, and undulating
sound. The compass of the Celeste is from C to C3.
In the pipe organ, all of the above tone qualities (Diapasons,
Flutes, and Strings) are derived from a pipe sound caused by
a vibrating column of air set in motion by the action of wind
impinging on a knife-like edge at the upper part of the pipe
mouth (a common toy whistle operates this way). These pipes
and their resulting sounds are classed collectively under the
name of Flue Stops.
THE REED STOPS
Pipe organ Reed Stops make use of the vibrations of a brass
reed tongue against a slotted brass tube, called a shallot.
The resulting impulses of wind are qualified in pitch and given
tonal shape by a resonator (of varying size and shape) placed
above the reed assembly. Reeds are of two basic types, solo
and chorus reeds. Solo Reeds are best used in a single melodic
line, and are generally of an imitative orchestral character.
The Great Clarinet 8' belongs in this family.