Rodgers 538 insignia, Owner'S Manual

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Rodgers 538/i548
21
Pitch designations
The tabs on your 538/i548 each have a pitch
designation, listed in “feet”, (8’, 4’, 16’, etc.).
8’ refers to
concert pitch ; a note played on an 8’ stop will have an
identical pitch as the same note played on a piano. 16’
represents an octave below concert pitch; a note played
on a 16’ stop will sound an octave below an 8’ stop.
This system of designating pitches represents the
approximate length of open organ pipes; the largest
pipe in an 8’ rank is approximately eight feet long; the
largest pipe in a 16’ rank is about sixteen feet long.
Other footages and their relationship to concert pitch
are listed in the table below:
When whole numbers are used (as shown in the table
above), it implies that the pitch of the stop is a certain
number of octaves above or below the 8’ pitch.
Mutation stops, on the other hand, are different in
that they have fractions in their pitch designations. This
means that their pitch falls somewhere other than on
the octave.
Mutations are most commonly found in the flute family
and are often used with other flute stops in solo
registrations or ensembles used in early organ music.
Because mutations often appear in divisions with a
number of other flute stops, a great diversity of solo
color can be achieved by using various combinations of
stops. See the following table for common solo
registrations utilizing mutations.
Larger organs will often have one or two mutation
stops from the principal family. In most cases, these
ranks are used to add color to the principal chorus.
Celeste ranks
Celestes are unique among organ stops in that they are
intentionally tuned sharp or flat in relation to the rest
of the instrument. Celestes are paired with a partner
rank (often called a “unison”), which is similar in color
to the celeste rank but is in tune with the balance of
the organ.
When the unison and celeste are drawn together, the
tuning discrepancy between the two ranks creates a
beautiful undulating quality suitable for lush, romantic
textures. Celestes are either from the string or flute
family, with the latter usually being the quieter of the
two.
Pitch Relationship to concert pitch
32’ two octaves below
16’ one octave below
8’ equal to concert pitch (also known as
“Unison”)
4’ one octave above
2’ two octaves above
1’ three octaves above
Mutation Common name Relationship to concert pitch
2-2/3’ Nazard one octave and a fifth
above
1-3/5’ Tierce two octaves and a third
above
1-1/3’ Quintflöte two octaves and a fifth
above
Registrations using mutations with other flute stops
8’ 4’ 2-2/3’ 2’ 1-3/5’ 1-1/3’
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Rodgers 538_i548.book Page 21 Monday, February 4, 2008 9:02 AM