KB3 Programs
Drawbars
D-2
Drawbars
The drawbars on a tone wheel organ emulate pipes of different lengths on a pipe organ. In
either case, they are controlled by changing the positions of a number of “stops”. As the
organist pulls out or pushes in these stops, he adds or reduces harmonics. Whether it’s pipes
or drawbars, though, the stops work like this: pull one out to add more of an overtone; push
it in to reduce the volume of the overtone.
The stops on the most popular tone wheel organs are: 16’, 51/3’, 8’, 4’, 22/3’, 2’, 13/5’, 11/3’.
and 1’. Note that they are still measured in feet, a carryover from pipe organ days. The 16’
and 51/3’ stops are considered the subharmonic group, while the third stop, 8’, produces the
fundamental of a tone, and stops 4-9 produce harmonics above the fundamental. By making
use of different combinations of these harmonics, a rich sort of additive synthesis is possible.
Best of all, you can make radical changes to the tone dynamically as you play.
The nine sliders of the Forte are set to control the drawbars, as listed in blue below the
sliders. Pulling the slider towards the keyboard increases the amount of the drawbar that is
heard.
KB3 Mode Buttons
The nine buttons above the sliders on the Forte have special capabilities in KB3 Mode that
are listed in blue, below the Multi Zone Mute Buttons and Programmable Switches. These
are:
Brake
Brake starts and stops the rotary speaker effect. This effect is not immediate, instead the
rotary speaker effect gradually slows down and speeds up, in a similar way that a real rotary
speaker reacts.
Chorus/Vibrato
On/Off
This parameter turns the chorus or vibrato effect on and off.
Chor/Vib
This parameter determines which modulation effect is used. The choice is Vibrato or Chorus
