Speaking Stops On The Trio 321 - Rodgers the trio Owner's Manual

SPEAKING STOPS
The speaking stops are grouped on the stop rail in a traditional
Theatre Organ console layout. On the extreme left are the pedal stops;
the accompaniment manual stops are next; then the great manual stops;
and finally , on the extreme right , the solo manual stops .
Each speaking stop tab is engraved with the full name of the
stop in italics at the top, the pitch designation (8', 4', etc.)
in
the
middle, and the abbreviation of the stop name in capital letters at
the bottom .
The designation of pitch by footage is the .same as the system used
in pipe organ nomenclature. An open pipe eight feet long produces the
lowest tone (bottom C on the manual) of an 8' stop. The 8' stops are
called the "Unison Pitch" of the organ. That is, Middle C played with
an 8' stop has the same pitch as Middle C on a piano. A 16' stop sounds
an octave below Unison Pitch, a 4' stop sounds an octave above, a 2' stop
sounds two octaves above, and a 1' stop sounds three octaves above.
In addition to the octave sounding stops, there are the "Mutation"
stops:
A 5-1/3' Quint
(sounds a fifth above Unison Pitch)
A 2-2/3' Twelfth
(sounds an octave and a fifth above Unison Pitch)
A 1-3/5' Tierce
(sounds two octaves and a third above Unison Pitch)
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