Mixtures; Mutations - Rodgers Deseret 115 Owner's Manual

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MIXTURES
Mixtures are generally composed of sets of unison and
off-unison pitches, which clarify and extend the upper
harmonic structure of the organ ensemble. They are used
generally in fuller registrations.
The Deseret 115 has three mixtures, each consisting of .
two ranks. Each has its own separate leveling control,
allowing for adjustments to be made according to the
requirements of the room in which the organ is placed.
MUTATIONS
Mutations are off-unison pitched stops whose purpose
is to add color to solo combinations. These stops are the
"salt and pepper" of registration, and should be freely
experimented with.
The 1-1/3' Larigot (Great) is a flute stop pitched
at two octaves and a major fifth above the unison (8')
pitch, usually used with Flutes at 8' and 4', or 8' and 2'.
The 2-2/3' Nazard (Swell) is the same pitch as the
Twelfth, but is a flute voice. If added to the 8' Rohr
Flute (Swell), its hollow half-stopped quality becomes more
apparent because of the reinforcement of that particular
harmonic of the 8' pitch.
The 1-3/5' Tierce is a flute pitched two octaves and
a major third above the unison (8').
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