Roland Music ATELIER AT300 Owner's Manual page 33

Selecting and Playing Sounds
What's the feet?
"Feet" is a term that began as a measurement of the length of the pipes
in a pipe organ.
The pipes that produce the basic pitch (fundamental) for each note are
considered to be "8 feet" in length.
Therefore, a pipe producing a pitch one octave below that of the
reference of 8' (eight feet) would be 16'; for one octave above the
reference, the pipe would be 4', and to take the pitch up yet another
octave it would be shortened to 2'.
The pitches of the harmonic bars are related as follows.
When the middle C (C4) note is pressed, each
harmonic bar will sound the following notes.
16' 5 1 / ' 8' 4' 2 2 / ' 2' 1 3 / ' 1 1 / ' 1'
3 3 5 3
15th
one octave 5th root 8th 12th 17th 19th 22nd
below
8' =
On tonewheel organs, the high-pitched footage for a portion of the high
range, and the low-pitched footage for a portion of the low range are
"folded-back" in units of one octave.
Folding back the high-frequency portion prevents the high-frequency
sounds from being unpleasantly shrill, and folding back the low-
frequency portion prevents the sound from becoming "muddy."
On the ATELIER faithfully simulates this characteristic.
31