SPECIFICATIONS
Input:
Dual 1/4" unbalanced
Output:
Dual 1/4" unbalanced
Input Impedance:
50k Ohms
Output Impedance:
100 Ohms
Output Level:
+5 dB max
Delay Time:
6 mS
Crossover Freq.
800 Hz
Size:
19 x 1.75 x 6 inches
Weight:
7 lbs
INTRODUCTION
Thank you for your purchase of the RFX147 Rotorhorn. This unit is a line level
rack mount signal processor for duplicating the sound of a rotating horn speaker
cabinet electronically. It has a two-way crossover network to produce the effect of
bass and treble "rotors". The unit is housed in a single space 19" rack painted
steel chassis and is intended for live performance or studio work. The RFX147 is
simple to use and is ready to work on power up.
FEATURES
• Accurate simulation of "Leslie" fast and slow speeds
• Front panel and footswitch control of all functions
• Smooth sounding CHORUS effect
• Mono VIBRATO effect
INSPECTON
1. Unpack and Inspect the RFX147 package
If obvious physical damage is noticed, contact the carrier immediately to make a
damage claim. We suggest saving the shipping carton and packing materials for
safely transporting the unit in the future.
2. Please complete the Warranty Registration Card and return it to the factory.
TABLE OF CONTENTS
1
Introduction
Features
Inspection
Table of Contents
DESCRIPTION
2
Front Panel
Rear Panel
CONNECTION
3
OPERATION
4
SCHEMATIC
5
SPECIFICATIONS
6
A brief history of the rotating speaker effect
WARRANTY
BACK COVER
BRIEF HISTORY OF THE ROTATING SPEAKER
Electronic devices that produce a “Leslie-like” sound have been available since
the sixties. Cheap solid state components and the need for more portable equip-
ment led to the development of numerous “electronic Leslies” and tremolo-vibrato
add-on devices. Few early Leslie simulators were authentic enough to fool even
causal listeners and rarely sounded like a real Leslie Speaker. Most relied on
simple phase-shift circuitry and their primary advantages were compactness and
low cost. Current equipment is much improved and it’s often difficult to tell the
difference between a real Leslie and a simulator, especially on recordings.
All mechanical rotary tremolo systems are based on the Doppler-effect. Discov-
ered by Austrian mathematician and physicist Christian Doppler (1803-1853) in
the early nineteenth century, the Doppler-effect is the apparent variation in pitch
that a stationary listener hears from a moving sound source. In practice, the
loudness of the sound also appears to vary and it is this combination of frequency
(vibrato) and ampli-tude (tremolo) modulation that give rotating speaker and other
Doppler-effect systems their characteristic sound.
Basic Doppler characteristics are easily created electronically. However, most
simulators don’t reflect sound or produce the unique audio characteristics of
mechanical systems. Rotating speaker elements also direct sound out the sides
and back of the cabinet which is reflected off nearby walls and surfaces. The
listener hears this combination of primary and reflected sound as a moving audio
field. Adding a second cabinet further enhances the effect. Even when the audio
source (organ) is mono, the rotating speaker elements and reflected sound create
a realistic stereo effect.
The RFX147 Rotorhorn simulates the Leslie speaker effect unlike any other
electronic simulator by utilizing an internal crossover. This provides a way to effect
the upper and lower frequencies differently much like a real rotating speaker. A
more authentic effect is thus produced.
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