Ring Modulator - E-Mu ProteusX Operation Manual

7 - Effects
Effects Descriptions

Ring Modulator

A ring modulator takes two signals and multiplies them together to produce an output
signal containing only the sum and difference frequencies of the two input waves. The
original frequencies are not output. If complex waveforms are used, every harmonic of
each signal multiplies every other according to its amplitude. Because ring modulation
is a linear process, these new sum and difference frequencies are displaced from their
normal exponential harmonic relationship. As a result, ring modulators tend to create
clangorous, bell-like timbres.
In this ring modulator, each side of the stereo input source is multiplied by an internal
sine wave oscillator. The internal oscillator can remain at a fixed pitch or it can be
modulated by an envelope follower.
The envelope follower sweeps the pitch of the modulating oscillator up or down based
on the amplitude of the input signal. Try adjusting the Proteus X attack and decay
controls (amp) to hear the effect of the envelope follower. The envelope follower can
sweep the modulating oscillator in either the positive or negative direction by setting
the value positive or negative.
Input 1
200 Hz
Input 2
800 Hz
Result
600 &
1000 Hz
This diagram shows the result of Ring Modulating two sine waves with frequencies of 200 Hz
& 800 Hz. Only the Sum and Difference frequencies of 600 Hz and 1000 Hz will be output.
Parameter Description
Frequency This control sets the frequency of the modulation waveform
Range: 0 Hz to 5000 Hz
Envelope Follower Controls how much the amplitude envelope sweeps the
modulating oscillator. Range: -10x to +10x
130
200
FREQUENCY (Hz)
800
FREQUENCY (Hz)
200 600 800 1000
FREQUENCY (Hz)
Proteus X Operation Manual