Treble Rotor
The indicator lamp provides visual feedback of the current treble rotation
rate.
The Slow speed sets the rotational speed of the treble rotor when the Rotator
Speed switch is set to Slow. This setting is continuously variable between 0
and 85 rpm. When the knob is centered you get a typical chorale effect.
The Fast speed setting determines the speed of the treble rotor when the
Rotator Speed switch is set to Fast. This setting is variable from 85 to 700
rpm. When the knob is centered you get a typical tremolo effect.
The Accel control sets the rate of change (acceleration or deceleration) when
the Rotator Speed switch is changed. The range of this setting is 0.1 to 20
seconds.
The Spread setting determines the difference between the left and right
microphone signals by moving the microphones apart a certain distance. This
provides a perceived “width” or stereo spread when the Rotator is spinning.
With Spread at minimum, both mics are in the same place. As Spread is
increased they move around the speaker cabinet in a circle, but in opposite
directions. With Spread at maximum they are at opposite sides.
Bass Rotor
These control work exactly like the Treble Rotor controls but this time they
affect the bass rotor.
The Single/Dual switch offers the possibility to have 2 Rotators running in a
stereo setting. A single Leslie cabinet is already stereo per se, but sometimes
more is better. With the Dual setup you get 2 complete Rotators spinning
in opposite directions and with slightly different speeds for that extra wide
sound.
Finally, the Distance control sets the apparent distance between the microphones
and the rotors. This affects the “amplitude modulation” of the mic’d sound
(the change in volume as the rotor horn passes the microphone). When the
microphones are at a small distance there is a lot of amplitude modulation,
making the sound pulsate.
