Roland VR-700 - Manual (Page 38)

40
Creating Organ Sounds
What is footage?
This comes from the length of pipes in a pipe organ. On a
pipe organ, the pipes that sound the fundamental pitch of
each key are considered by convention to have a length of
eight feet (8’). A pipe that is half this length will produce a
pitch that is one octave higher, and a pipe that is double this
length will produce a pitch that is one octave lower. Thus, the
sixteen-foot (16’) pipe is one octave lower, and the four-foot
(4’) pipe is one octave higher.
A tonewheel organ’s overtone structure
In certain regions of a tonewheel organ’s keyboard, the
overtones will not correspond to the configuration of the
harmonic bars. In order to prevent unpleasantly high or low
pitches, the high footage is “folded back down” in one-
octave units for the high range, while the low footage is
“folded back up” in one-octave units for the low range. The
VR-700 faithfully reproduces this characteristic of tonewheel
organs.
How the harmonic bars are arranged
If you take a look at how the harmonic bars are arranged,
you’ll notice that the 5-1/3’ footage alone is not located in
the order of its pitch. This is because the 5-1/3’ pitch is not a
multiple of the 8’ pitch, but a multiple (the third harmonic) of
the 16’ pitch. In general, sounds consisting only of overtones
that are integer multiples will sound consonant, while sounds
that contain non-integer multiples will sound muddy. Since
the 5-1/3’ pitch is more easily understood as an overtone of a
16’ fundamental, the 5-1/3’ harmonic bar is placed beside the
16’ harmonic bar.
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